Social and professional recognition are key determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals (AP-HP ALADDIN COVID-19 survey).

OBJECTIVE: Documenting the perceptions and experiences of frontline healthcare workers during a sanitary crisis is key to reinforce healthcare systems. We identify the determinants of quality of working life (QWL) among night-shift healthcare workers (NSHW) in Paris public hospitals shortly after the first-wave of the COVID-19 pandemic.
METHODS: The ALADDIN cross-sectional online survey (15 June to 15 September 2020) collected QWL, socio-economic, behavioral, and work-related information among 1,387 NSHW in the 39 hospitals of the Assistance Publique-Hôpitaux de Paris (AP-HP). Data were weighted (margin calibration) to be representative of the entire population of 12,000 AP-HP hospitals' NSHW regarding sex, age, and professional category. Linear regression was used to identify correlates of QWL (WRQoL scale).
RESULTS: New night position during the COVID pandemic, difficulties in getting screened for COVID, and considering protective measures inadequate were associated with poorer QWL, after adjustment for socio-economic characteristics, professional category, perceived health, physical activity, and history of harassment at work. Under-estimation of night-shift work by day-shift colleagues, reporting night work as a source of tension with friends, or feeling more irritable since working at night also impaired QWL. By contrast, satisfaction regarding COVID information received from the employer, and feeling valued by the general population during the pandemic improved QWL.
CONCLUSIONS: Insufficient access to screening, information, and protective measures impaired QWL of NSHW after the first wave of COVID-19 in Paris public hospitals. Social and professional recognition of night-shift work were the key determinants of QWL in this population.

Introduction

The number of individuals involved in night-shift work has increased in the last twenty years in Western countries, and people working in the healthcare sector are among the most represented [1-3]. Night-shift work negatively impacts health, notably because of circadian rhythms perturbations [4-8]. Its multiple potential consequences include fatigue, sleep disturbance, an increased risk of cancer, cardiovascular diseases, metabolic syndrome, affective disorders, and impaired cognitive function [9-19]. Beyond these negative health consequences, night-shift work has also detrimental effects on quality of life [20-22], which closely interacts with perceived health. Quality of working life (QWL), a multidimensional definition of well-being in the workplace, directly influences quality of life [23]. QWL is closely linked to factors such as workload, work-life balance, meaning of work and meaning at work [24, 25], the latter two factors distinguishing how one individual perceives the meaning of what one does at work from the group to which one self-identifies in said work environment [26]. A recent literature review targeting healthcare work showed that QWL may also influence quality of care [27]. In the COVID-19 era, QWL remains poorly documented among hospital night-shift healthcare workers (NSHW), a population exposed to a higher risk of infection [28], and who contributes to the continuity of care since the beginning of the pandemic. Managing healthcare systems during sanitary crises represents human and organizational challenges with potential mental health and quality of life implications [29]. A better understanding of QWL among NSHW is therefore needed, both from a public health perspective, and to identify levers which could help strengthening healthcare systems in such contexts.

The present study aims to document QWL among NSHW in Paris public hospitals shortly after the first-wave of the COVID-19 pandemic and to identify its determinants.

Materials and methods

The AP-HP ALADDIN survey

The ALADDIN cross-sectional survey (15 June 2020 to 15 September 2020) was conducted among NSHW in public hospitals in Paris. It included all 39 hospitals of the Assistance Publique—Hôpitaux de Paris (AP-HP). One of the main objectives was to document NSHW’s QWL (i.e. perceived quality of life at work) and its correlates shortly after the first wave of the COVID-19 pandemic (March to May 2020), once healthcare workers were more available to participate in the survey. All individuals working in the AP-HP hospitals with a night-shift or a day/night alternation employment contract, regardless the years of experience, working full-time or part-time, could participate in the survey. Exclusion criteria were as follows: (i) working only during the day; (ii) working less than three hours a day between 9 p.m. and 6 a.m. twice a week (including on-duty or on-call staff). In order to maintain a homogeneous study population, physicians were excluded from the analyses as they constitute a subgroup with specific characteristics. Sample size was expected to reach 10% of the 12,000 NSHW working in the AP-HP hospitals (target population).

Ethics

The AP-HP ALADDIN survey was approved by the Lyon 2 ethics committee in March 2020 (ID RCB202-A00495-34). Informed consent was obtained for all survey participants.

Data collection

During the AP-HP ALADDIN survey, quantitative data were collected using an online questionnaire which documented participants’ sociodemographic, economic and work-related characteristics, perceived health, QWL, as well as perceptions and experience since the beginning of the COVID-19 pandemic [30, 31]. NSHW’s perceptions regarding their social and professional recognition were assessed using items related to under-estimation of night-shift work by colleagues, loved ones, and patients; perceptions of the importance of night missions and of workload during night; feeling valued by the general population as a NSHW during the pandemic. Most of these items were derived from different stigma scales [32-34]. NSHW could respond to the questionnaire online (NetSurvey®), using either their computer at work or their personal electronic devices.

Assessment of QWL

NSHW’s QWL was assessed using the work-related quality of life (WRQoL) scale [35] which includes 24 items, each associated with five possible answers on a Likert-type scale (strongly disagree/disagree/neutral/agree/strongly agree). The WRQoL scale explores six dimensions of quality of life related to the work environment of NSHW. Each dimension is associated with a factor score, calculated from respondents’ answers to the first 23 items of the scale: general well-being (GWB, score range: 0 to 30); home-work interface (HWI, score range: 0 to 15); job and career satisfaction (JCS, score range: 0 to 30); control at work (CAW, score range: 0 to 15); working conditions (WCS, score range: 0 to 15); and stress at work (SAW, score range: 0 to 10) [36]. For each dimension, higher score values denote better QWL. A full-scale score, ranging from 0 to 115, can also be calculated as the sum of the six factor scores. The 24th item of the scale, which explores NSHW’s satisfaction with the overall quality of their working life, is not used in the calculation of factor scores.

Study population

The study population included survey participants who filled out the WRQoL scale.

Statistical analyses

Data were weighted and calibrated (calibration on margins using the raking ratio method) to be representative of the whole population of the 12,000 NSHW working in the AP-HP hospitals in terms of sex, age (using 5-year age classes), and professional category (nurses, nurse assistants and laboratory technicians, executives, midwives, and other categories). Descriptive statistics were used to document NSHW’s answers to the questionnaire items and the distribution of QWL scores in the whole study population. Comparisons were then performed between professional categories using chi-square tests for categorical variables and Wald tests for continuous ones. Lastly, weighted linear regression models were used to identify correlates of the WRQoL full-scale score. Variables with a p-value <0.25 in the univariable analyses were considered eligible for the multivariable model. A backward selection procedure was used to build the final multivariable model, which included only statistically significant variables (p<0.05). The Stata version 14.2 for Windows software (StataCorp, College Station, Texas, USA) was used for the analyses.

Results

Characteristics of the study population

The study population included 1,387 individuals, and mainly comprised nurses (52.3%). The other professional categories represented were nurse assistant or technicians (38.2%), midwives (4.2%), executives (0.8%), and other categories (4.6%). The latter group included different professions such as reception agents, administrative staff, or pharmacists.

NSHW in the study population were mostly women (77.5%). Mean age (standard deviation, SD) was 39.3 (12.0 years), 54.2% of NSHW were living with a partner, and 50.2% had children (Table 1A). Fourteen percent of NSHW reported facing financial difficulties. Three quarters (75.8%) had a permanent night position and 61.2% worked in a hospital department for adult care. The mean (SD) seniority as a night-shift worker was 9.0 (8.5) years (Table 1B). Socio-demographic, economic, and work-related characteristics differed significantly between professional categories of NSHW (Table 1A to 1E).

Table 1

Main characteristics of night-shift healthcare workers according to their professional category (n = 1,387, AP-HP ALADDIN survey, Paris public hospitals).

		Professional category of NSHW
Characteristics	Whole study population	Nurses	Assistant nurses or technicians	Midwives	Executives	Other categories	p-value 1
	(n = 1,387)	(52.3%)	(38.2%)	(4.2%)	(0.8%)	(4.6%)
	Percent [95% CI ♦ ] or mean (SD)
a. Socio-demographic and economic characteristics
Female gender	77.5 [75.1–79.9]	82.4	71.2	96.1	71.2	58.4	<0.001
Age— in years	39.3 (12.0)	36.5 (10.7)	43.4 (10.3)	33.1 (8.0)	51.8 (9.5)	40.3 (11.7)	<0.001
Matrimonial status							<0.001
• single	36.6 [34.0–39.2]	43.2	29.4	29.2	13.1	32.8
• in cohabitation	20.8 [18.6–23.0]	21.1	18.9	35.3	16.6	20.9
• in civil partnership or married	33.4 [30.8–35.9]	28.8	39.7	35.6	43.8	29.4
• widow or widower	9.2 [7.6–10.9]	7.0	12.1	0	26.5	16.9
Has children							<0.001
• no	49.8 [47.1–52.6]	60.9	33.3	67.8	24.9	49.9
• yes, and at least one lives at home	42.4 [39.7–45.1]	36.9	52.1	32.2	49.5	32.7
• yes, but none at home	7.8 [6.1–9.5]	2.2	14.7	0	25.6	17.4
Has partial or complete custody of at least one child	40.5 [37.8–43.1]	36.0	47.8	32.2	47.6	36.3	<0.001
Perceived financial status							<0.001
• Feels financially comfortable/it’s okay	40.0 [37.3–42.7]	44.9	28.9	84.5	62.0	32.8
• Has to be careful	46.0 [43.3–48.7]	46.1	50.1	15.5	35.4	40.5
• Faces financial difficulties	14.0 [11.9–16.0]	9.0	21.0	0	2.6	26.7
b. Work-related characteristics
Type of position							<0.001
• Permanent night position	75.8 [73.3–78.2]	76.1	84.7	4.9	84.1	61.2
• Replacement (“pool”)	4.3 [3.2–5.4]	4.4	4.9	0	0	3.7
• Position with day/night alternation	16.2 [14.1–18.3]	16.7	8.0	95.1	3.8	9
• New night-shift position during the pandemic	0.8 [0.3–1.3]	0.9	0.9	0	0	0
• Other	2.9 [1.7–4.1]	2.0	1.5	0	12.1	26.2
Hospital department							<0.001
• Pediatric	15.1 [13.2–17.1]	16.9	14.7	4.9	1.4	10.5
• Adults	61.2 [58.5–63.9]	66.5	60.6	46.6	23.9	25.8
• Several departments*	23.7 [21.3–26.0]	16.6	24.7	48.5	74.7	63.7
Hospital unit							<0.001
• Surgery	16.4 [14.3–18.5]	16.7	15.4	37.2	9.3	3.7
• Geriatrics/Rehabilitation	8.8 [7.2–10.5]	6.9	14.0	0	3.3	0
• Internal medicine/Infectiology/Cardiology/Pneumology	7.3 [6.0–8.6]	9.1	5.8	0	1.2	7.3
• Neurology/Nephrology/Oncology/Endocrinology	6.5 [5.2–7.8]	8.7	5.1	0	2.4	0
• Pediatrics	15.7 [13.7–17.7]	17.3	15.8	4.9	1.4	10.5
• Resuscitation	13.4 [11.7–15.2]	17.9	10.2	0	0	3.6
• Emergency	7.2 [5.7–8.7]	6.5	7.4	9.4	7.6	11.1
• Several units*	24.5 [22.1–27]	16.9	26.5	48.5	74.7	63.7
Seniority as a night-shift worker —in years	9.0 (8.5)	8.4 (8.1)	9.5 (8.0)	9.7 (6.1)	14.3 (10.6)	7.8 (9.2)	<0.001
Daily duration of work							<0.001
• 10 hours	62.1 [59.5–64.8]	61.3	72.7	0	80.2	38.1
• 12 hours	34.0 [31.4–36.6]	36.2	25.1	96.6	8.0	29.9
• other	3.9 [2.6–5.2]	2.5	2.3	3.4	11.8	32.0
Part-time work	5.2 [4.0–6.4]	5.7	4.3	9.1	7.3	3.2	0.466
Travel time to work (home-work one-way commute)— in minutes	42 (36)	42 (24)	48 (36)	48 (54)	36 (24)	48 (24)	0.035
c. Health-related characteristics
Perceived health							0.019
• Bad or very bad	8.3 [6.7–9.9]	8.5	7.4	4.9	7.7	17.4
• Fair	40.5 [37.7–43.2]	40.2	41.8	25.1	40.9	47.0
• Good or excellent	51.3 [48.5–54]	51.3	50.8	70.1	51.4	35.6
Practice of any physical activity	54.2 [51.2–57.1]	52.5	53.4	85.5	39.2	52.8	<0.001
Perception of a change in weight since working at night (309 missing values)	68.2 [65.3–71.1]	68.1	69.8	45.0	68.1	70.6	0.251
History of cancer	3.8 [2.6–5.1]	3.5	3.4	3.4	4.6	12.5	0.026
History of psychiatric troubles (depression, bipolar disorders, etc.)	5.3 [3.9–6.7]	4.1	5.1	7.8	10.9	17.6	0.001
History of sexual or moral harassment at work	20.9 [18.5–23.4]	20.6	21.7	12.1	39.6	23.3	0.323
History of SARS-CoV-2 infection							0.014
• No	58.7 [56.0–61.4]	60.0	60.3	43.3	59.2	44.2
• Yes	13.6 [11.7–15.5]	14.1	13.3	9.6	14.0	14.5
• Did not answer	27.7 [25.2–30.2]	25.9	26.4	47.1	26.8	41.3
d. Work-related perceptions
Night-shift work is often or always under-estimated by colleagues working during the day2	64.7 [62.0–67.4]	67.1	69.6	28.0	73.6	29.9	<0.001
Night-shift work is often or always under-estimated by loved ones2,3	21.9 [19.6–24.2]	24.3	17.6	36.8	14.0	17.4	0.003
Night-shift work is often or always under-estimated by patients 2	18.3 [16.2–20.4]	20.2	16.9	12.2	18.2	13.6	0.322
Day missions are more important than night missions4	24.0 [21.7–26.3]	23.9	25.2	12.7	17.0	27.6	0.271
Day workload is higher than night workload 4	38.5 [35.8–41.2]	42.7	33.7	18.7	17.7	52.8	<0.001
Work rhythm is a source of tension with partner or children (30.9% in the “not concerned” category)	47.2 [43.1–51.3]	56.8	33.1	79.5	32.2	54.0	<0.001
Work rhythm is a source of tension with friends	20.1 [17.9–22.4]	24.3	11.6	34.4	27.0	28.4	<0.001
Feels more irritable since works at night	43.6 [40.7–46.5]	48.7	33.6	72.8	30.1	40.3	<0.001
e. Changes in work organization since the beginning of the COVID-19 pandemic
No change at all	36.8 [34.1–39.5]	32.5	42.8	25.4	23.2	49.8	<0.001
Change of department	25.8 [23.5–28.2]	27.8	27.3	2.8	14.3	14.0	<0.001
Change of ward (part of department)	29.8 [27.3–32.2]	33.2	31.1	0	13.6	10.8	<0.001
Increase of the no. of working hours	37.2 [34.6–39.9]	39.3	29.0	71.8	65.5	45.5	<0.001
Switch to night-shift work	5.2 [3.9–6.6]	5.0	4.4	4.9	5.6	15.9	0.005
Change of activity to manage COVID patients	19.0 [16.9–21.1]	23.7	15.2	14.4	8.1	3.9	<0.001
f. COVID-related items
Satisfied of the information on COVID received from the employer 5	31.5 [29.0–34.0]	30.2	32.2	34.1	54.1	34.5	0.440
Feels vulnerable to COVID-19 because of professional activity 6	77.8 [75.3–80.3]	80.4	73.7	89.4	63.0	72.9	0.015
Fears to get the COVID-19 at work	65.5 [62.7–68.3]	64.2	67.0	73.7	44.3	65.0	0.368
Fears to transmit the COVID-19 to close relatives	90.6 [88.9–92.4]	90.4	90.5	96.5	79.3	91.3	0.477
Has received psychological support from close relatives during the previous two weeks	7.0 [5.4–8.5]	7.6	7.4	0	2.0	4.3	0.286
Has received psychological support from a professional during the previous two weeks	8.4 [6.7–10.1]	8.4	9.6	0	3.3	8.1	0.236
Felt valued by the general population as a NSHW during the pandemic	62.9 [60.1–65.8]	65.0	59.2	76.9	63.0	55.8	0.067
Is confident in the health authorities to manage the crisis 6	19.6 [17.3–22.0]	18.6	20.4	23.1	43.1	17.7	0.346
Faced difficulties in applying protective measures against COVID 6	59.7 [56.8–62.6]	59.2	58.9	69.1	44.9	65.9	0.454
Considers protective measures inadequate6	27.6 [24.9–30.2]	27.6	28.5	23.6	10.9	25.7	0.727
Faced difficulties in getting screened for SARS-CoV-2 infection6	58.4 [55.5–61.4]	57.8	62.3	56.9	37.3	38.8	0.013

CI = confidence interval; NSHW = night-shift healthcare workers; SD = standard deviation.

♦ For the purpose of readability of the table, 95% confidence intervals are only presented for the characteristics of the whole study population.

* Concerns healthcare workers assigned to different departments or units.

1 Comparison of characteristics between the five professional categories of NSHW (Chi-square tests for categorical variables, Wald test for continuous variables).

2 The other possible answers to this item of the questionnaire included “never”, “rarely”, and “from time to time”.

3 Loved ones included partner, family, and friends.

4 “I totally agree” or “I agree” (versus “I totally disagree” or “I disagree”).

5 “The information on protective measures against COVID that I received from my employer were sufficient and complete.”

6 “I totally agree” or “I agree” (versus “I totally disagree”, “I disagree”, or “no interest”).

Health-related characteristics

In the whole study population, 51.3% perceived their health as good or excellent, and 54.2% reported physical activity, with highest rates among midwives for these two characteristics (Table 1C). Twenty-one percent (20.9%) of NSHW had faced sexual or moral harassment at work. Nearly fourteen percent of NSHW (13.6%) reported they had contracted COVID-19, but 27.7% did not answer the corresponding item of the questionnaire.

Work-related perceptions

Globally, 64.7% of NSHW perceived that night-shift work was often or always under-estimated by their colleagues working during day, and this percentage was highest among executives (Table 1D). Concerning the social consequences of work, 47.2% of NSHW with a partner or children reported work rhythm was a source of tension between one another, 20.1% of NSHW reported work rhythm as a source of tension with friends, and 43.6% felt more irritable since they worked at night. The percentages were highest among midwives for these three characteristics.

Changes in work organization since the beginning of the COVID-19 pandemic

Regarding work organization, 36.8% of NSHW reported no change since the beginning of the COVID-19 pandemic, a percentage that was highest in the “other categories” group (Table 1E). Both globally and almost consistently within professional categories, the changes more often reported were increase in the number of working hours (globally 37.2% of NSHW) and change of ward (part of department dedicated to a given specialty) (29.8%). Less than one percent (0.8%) had a new night-shift position since the beginning of COVID-19. Nineteen percent of NSHW changed activity to manage COVID-19 patients, and this percentage was highest among nurses.

COVID-related items

NSHW’s responses to the COVID-19 items of the questionnaire showed that most NSHW (77.8%) felt vulnerable to COVID-19 because of their professional activity and 90.6% of them feared to transmit the virus to close relatives (Table 1F). About one third (31.5%) reported that the information their employer gave them on COVID-19 was sufficient and complete, 58.4% faced difficulties in getting screened, 59.7% reported difficulties in applying protective measures against COVID-19, which 27.6% considered inadequate. A total of 19.6% of NSHW felt confident in the health authorities’ ability to manage the crisis. Finally, while 62.9% felt valued by the general population as a NSHW during the pandemic, 7.0% and 8.4% reported having received recent psychological support from close relatives and professionals, respectively (Table 1). No significant difference between professional categories were found concerning NSHW’s responses to the COVID-related items of the questionnaire, except for the percentage of NSHW who felt vulnerable to COVID-19 due to their professional activity (highest among midwives) and that facing difficulties in getting screened for SARS-CoV-2 infection (highest among assistant nurses or technicians).

Distribution of QWL scores

Median [interquartile range, IQR] WRQoL full-scale score was 71 [63-78] in the whole study population (Fig 1). Its distribution was significantly different between professional categories, with the highest score observed amongst executives, and the lowest amongst nurses (in mean (SD): 73 (5.8) versus 69.6 (10.6), p = 0.001) (Table 2). The distributions of scores for the six dimensions of QWL are also presented in Table 2. Except for general well-being, in addition to job and career satisfaction, significant differences—globally below 1 or 2 points in median, with a maximum of 3 points—were observed between the QWL scores for the different professional categories. Midwives had the lowest QWL scores for home-work interface, working conditions, and stress at work (meaning impaired QWL for these three dimensions) along with the highest QWL score (meaning better QWL) for control at work. Executives presented higher scores in the “Home-work interface” and “Job and career satisfaction” dimensions of QWL, compared with the other professional categories.

Fig 1

Boxplots of quality of working life scores among night-shift healthcare workers according to their professional category (n = 1,387, AP-HP ALADDIN survey, Paris public hospitals).

The boxplots present median values and interquartile ranges (box) for the full-scale WRQoL score (range 0 to 115). Lines (whiskers) include all points within 1.5 interquartile range of the nearest quartile. Higher score values denote better QWL.

Table 2

Mean quality of working life scores among night-shift healthcare workers according to their professional category (n = 1,387, AP-HP ALADDIN survey, Paris public hospitals).

Scores calculated from the WRQoL scale1 [35] (range)		Professional category of NSHW
	Whole study population (n = 1,387)	Nurses (52.3%)	Assistant nurses or technicians (38.2%)	Midwives (4.2%)	Executives (0.8%)	Other categories (4.6%)	p-value 2
	mean (SD)
GLOBAL WORK-RELATED QUALITY OF LIFE SCORE
Full-scale WRQoL score (0 to 115)	70.5 (12.0)	69.6 (10.6)	71.7 (14.2)	70.2 (15.7)	73.0 (5.8)	70.9 (20.1)	0.001
SCORES ASSOCIATED WITH THE SIX DIMENSIONS OF WORK-RELATED QUALITY OF LIFE
General well-being (GWB) (0 to 30)	19.3 (4.2)	19.2 (3.8)	19.5 (4.9)	19.3 (5.3)	19.2 (1.9)	19.5 (7.1)	0.844
Home-work interface (HWI) (0 to 15)	9.2 (2.1)	9 (1.9)	9.4 (2.4)	8.4 (2.9)	9.6 (1.0)	9.6 (2.7)	<0.001
Job and career satisfaction (JCS) (0 to 30)	18.8 (3.8)	18.7 (3.2)	18.9 (4.5)	19.4 (6.2)	20.4 (1.8)	18.6 (7.2)	0.060
Control at work (CAW) (0 to 15)	9.3 (2.6)	9.2 (2.3)	9.4 (3.0)	10.3 (3.5)	9.9 (1.1)	8.7 (4.7)	0.025
Working conditions (WCS) (0 to 15)	8.2 (2.6)	8.0 (2.4)	8.5 (2.9)	7.7 (3.1)	8.8 (1.2)	8.7 (3.9)	0.021
Stress at work (SAW) (0 to 10)	5.7 (1.9)	5.6 (1.7)	6.0 (2.1)	5.1 (2.4)	5.2 (0.9)	5.9 (3.0)	0.002

NSHW = night-shift healthcare workers; IQR = interquartile range; SD = standard deviation; WRQoL = work-related quality of life.

1 For each score, higher values denote better quality of working life.

2 Comparison of mean scores between the five professional categories of NSHW (Wald test).

Determinants of QWL

In the multivariable QWL model, satisfaction on the information on COVID received from the employer and feeling valued by the general population as a NSHW during the pandemic were identified as independent correlates of higher full-scale WRQoL score (Table 3), after adjustment for socio-economic characteristics (matrimonial status, professional category, financial difficulties, hospital unit of assignment), perceived health, history of harassment at work, and physical activity.

Table 3

Factors associated with quality of working life among night-shift healthcare workers: Linear regression models with full-scale WRQoL score as the outcome (n = 1,387, ALADDIN survey, Paris public hospitals).

	Univariable models			Multivariable model (n = 1,124)
Characteristics	Coefficient	[95% CI]	p-value	Adjusted coefficient	[95% CI]	p-value
SOCIO-DEMOGRAPHIC AND ECONOMIC CHARACTERISTICS
Matrimonial status
• single	ref	ref		ref	ref
• in cohabitation	0.51	[-1.55; 2.56]	0.627	1.03	[-0.68; 2.74]	0.238
• in civil partnership or married	1.17	[-0.54; 2.87]	0.181	0.18	[-1.32; 1.68]	0.814
• widow or widower	3.37	[0.97; 5.76]	0.006	2.45	[0.09; 4.81]	0.042
Perceived financial status
• Feels financially comfortable/it’s okay	ref	ref		ref	ref
• Has to be careful	-3.58	[-5.09; -2.07]	<0.001	-2.07	[-3.49; -0.65]	0.004
• Faces financial difficulties	-6.65	[-9.05; -4.26]	<0.001	-4.87	[-7.17; -2.58]	<0.001
WORK-RELATED CHARACTERISTICS
Professional category
• Nurses	ref	ref		ref	ref
• Assistant nurses or technicians	2.08	[0.52; 3.63]	0.009	1.93	[0.50; 3.37]	0.008
• Midwives	0.53	[-3.99; 5.05]	0.819	0.13	[-4.06; 4.33]	0.950
• Executives	3.38	[-0.21; 6.98]	0.065	1.68	[-1.18; 4.54]	0.250
• Other categories	1.30	[-3.68; 6.27]	0.609	0.62	[-3.36; 4.60]	0.760
Type of position
• Permanent night position	ref	ref
• Replacement (“pool”)	-2.70	[-7.01; 1.62]	0.220	-2.33	[-5.28; 0.63]	0.123
• Position with day/night alternation	-0.32	[-2.02; 1.38]	0.709	-1.87	[-4.10; 0.36]	0.100
• New night-shift position during the COVID pandemic	-13.43	[-25.37; -1.50]	0.027	-12.56	[-23.81; -1.31]	0.029
• Other	-0.02	[-5.07; 5.04]	0.995	-0.37	[-4.76; 4.02]	0.869
Hospital unit
• Surgery	ref	ref		ref	ref
• Geriatrics/Rehabilitation	4.96	[1.79; 8.12]	0.002	2.92	[0.22; 5.63]	0.034
• Internal medicine/Infectiology/Cardiology/Pneumology	0.82	[-2.27; 3.92]	0.602	1.03	[-1.71; 3.76]	0.461
• Neurology/Nephrology/Oncology/Endocrinology	2.00	[-1.22; 5.21]	0.224	1.80	[-1.07; 4.67]	0.218
• Pediatrics	2.89	[0.20; 5.58]	0.035	1.33	[-0.99; 3.65]	0.262
• Resuscitation	2.24	[0.04; 4.43]	0.046	3.00	[0.89; 5.11]	0.005
• Emergency	1.09	[-2.14;4.32]	0.508	1.48	[-1.24; 4.21]	0.286
• Several units	1.87	[-0.21; 3.95]	0.077	1.32	[-0.66; 3.31]	0.191
HEALTH-RELATED CHARACTERISTICS
Perceived health
• Bad or very bad	ref	ref		ref	ref
• Fair	7.39	[4.20; 10.57]	<0.001	4.98	[2.20; 7.76]	<0.001
• Good or excellent	13.56	[10.4; 16.72]	<0.001	8.80	[5.99; 11.61]	<0.001
Practice of any physical activity	3.54	[2.05; 5.03]	<0.001	1.33	[0.08; 2.57]	0.037
History of sexual or moral harassment at work	-5.36	[-7.36; -3.35]	<0.001	-3.70	[-5.42; -1.98]	<0.001
WORK-RELATED PERCEPTIONS
Night-shift work is often or always under-estimated by colleagues working during the day 1	-3.95	[-5.57; -2.32]	<0.001	-3.54	[-5.01; -2.08]	<0.001
Work rhythm is a source of tension with friends	-7.11	[-9.08; -5.14]	<0.001	-2.28	[-4.14; -0.42]	0.016
Feels more irritable since works at night	-5.46	[-6.92; -3.99]	<0.001	-2.96	[-4.34; -1.58]	<0.001
WORK ORGANIZATION: CHANGES SINCE THE BEGINNING OF THE COVID PANDEMIC
COVID-RELATED ITEMS
Satisfied of the information on COVID received from the employer 4	7.36	[5.86; 8.85]	<0.001	4.67	[3.26; 6.07]	<0.001
Felt valued by the general population as a NSHW during the pandemic	3.12	[1.52; 4.71]	<0.001	1.41	[0.13; 2.70]	0.031
Considers protective measures inadequate 5	-5.28	[-6.98; -3.57]	<0.001	-2.09	[-3.52; -0.65]	0.004
Faced difficulties in getting screened for SARS-CoV-2 infection 5	-4.38	[-5.89; -2.88]	<0.001	-2.95	[-4.25; -1.65]	<0.001

CI = confidence interval; WRQoL = work-related quality of life.

♦ This variable was not entered in the multivariable analysis due to a high rate of NSHW in the “not concerned” category.

1 The other possible answers to this item of the questionnaire included “never”, “rarely”, and “from time to time”.

2 Loved ones included partner, family, and friends.

3 “I totally agree” or “I agree” (versus “I totally disagree” or “I disagree”).

4 “The information on protective measures against COVID that I received from my employer were sufficient and complete.”

5 “I totally agree” or “I agree” (versus “I totally disagree”, “I disagree”, or “no interest”).

By contrast, a new night-shift position during the pandemic, under-estimation of night-shift work by colleagues working during the day, work rhythm as a source of tension with friends, feeling more irritable since working at night, considering protective measures against the COVID-19 inadequate, and having faced difficulties in getting screened for SARS-CoV-2 infection were all independent correlates of lower full-scale WRQoL score.

Discussion

This representative survey offers a comprehensive picture of perceived quality of life at work among NSHW in Paris hospitals shortly after the first wave of the COVID-19 pandemic. After adjustment for socio-demographic, professional, and health-related characteristics, both social and professional recognition of night-shift work appeared as key determinants of QWL in this population. By contrast, lack of or insufficient access to screening, information, and protective measures significantly impaired QWL.

These findings highlight the impact on QWL of the difficulties faced by hospital teams to organize the chain of information and to provide safety equipment to all caregivers during the first wave of COVID-19, despite their preparedness and training for emergency situations. Indeed, this unexpected global health crisis caused by a previously unknown virus has deeply challenged healthcare workers’ adaptability [37], and has stressed the need to update safety guidelines to protect and prevent infection in hospital workers [38]. Another study in the COVID-19 context underlined that coping strategies could influence healthcare workers’ well-being and QWL [39]. Findings from ALADDIN also highlight the importance of recognizing the contribution of all healthcare workers [37]. Previous work showed that emphasizing the value of healthcare workers’ role was essential to motivate them and to increase their willingness to work during public health emergency situations [40]. Professional recognition also includes feeling supported by peers. In the ALADDIN survey, 64.7% of NSHW reported that night-shift work is often or always under-estimated by colleagues working during the day, and this perceived stigma had a significant detrimental effect on QWL. These findings highlight the need to develop interventions to improve communication, sharing of experiences, and support between day-shift and night-shift hospital healthcare workers. Such interventions can reinforce the sense of community among healthcare workers, and have the potential to improve NSHW’s experience in the workplace. In addition, findings confirm that healthcare workers’ perception of their public image can influence their QWL [41].

Results from the univariable analyses confirm the detrimental effect on QWL of self-perceived vulnerability to COVID-19 and fear of transmitting the infection to close relatives. Previous research has also shown a negative psychological impact of these two factors among healthcare workers in France [42]. Interestingly, in ALADDIN, these factors were not identified as independent correlates of QWL in the final multivariable model, maybe because of their correlation with other COVID-related variables such as difficulties to get screened and perceived inadequate and insufficient protective measures. In the same way, changes in work organization since the beginning of the pandemic did not remain in the model after multivariable adjustment.

There is a lack of published studies on QWL conducted among healthcare workers, especially in France. We identified only one recent survey, also based on the WRQoL scale [43]. QWL level observed in ALADDIN was lower than that found in this recent survey, conducted among 2,040 French anesthesiologists (median [IQR] WRQoL full-scale score: 71 [63-78] versus 77 [66-85]) [43]. This difference is likely to be related to the study period, as the latter survey was performed before the beginning of the COVID-19 pandemic (January to June 2019). It may also be related to the diversity of professional categories participating in ALADDIN, presenting different levels of QWL.

Compared with the WRQoL scale’s norms, the median QWL score in ALADDIN corresponds to a relatively low level of QWL. However, these norms refer to the UK National Health Services [36], and may not be adapted to the French context because of differences between countries in the organization and functioning of healthcare services. Cultural specificities may also play a role, as shown in other research areas such as perception of happiness [44]. These specificities may be linked to differences in people’s work-related representations and expectancies. Environmental factors such as the socio-political context in different countries may make international comparisons even more difficult.

Findings from ALADDIN showed statistically significant differences in QWL between professional categories. These differences were however of modest magnitude and did not exceed 3 points in QWL scores. Further research is needed to determine if such a magnitude exceeds the minimum important difference for the WRQoL scale. Executives showed both the best overall QWL and higher scores in the “Home-work interface” and “Job and career satisfaction” dimensions of QWL, compared with that of other professional categories. Along with older age, correlated with less domestic responsibilities related to child care, a longer experience of night-shift work may explain the greater ability of executives to find the right balance between their professional and personal lives. By contrast, executives (together with midwives) presented a low score of QWL in the “Stress at work” dimension, revealing higher levels of stress than other professional categories. Interestingly, midwives reported the lowest QWL related to working conditions. Further research should thus be performed to identify midwives’ specific needs and expectations to both improve their QWL and prevent psychosocial risks [45]. Of note, the number of years in night-shift work (variable “seniority as a night-shift worker (in years)”) was not significantly associated with overall QWL, despite its heterogeneity in our study sample. We hypothesize that seniority may influence one’s night-shift work experience in different ways. For instance, workers with more night-shift work experience may better cope with stress than those with less experience. By contrast, the latter may have been less exposed to changes in the circadian rhythm, resulting in better perceived health.

The ALADDIN survey has several strengths. First, its representativeness regarding sex, age, and professional categories allows presenting a snapshot of QWL among all NSHW working in Paris public hospitals. Second, the choice of the study period, which directly followed the first wave of COVID-19 in France (March to June 2020), is adequate to assess NSHW’s perceptions during the pandemic. Indeed, once their work overload started to decline after the peak of the crisis, NSHW were more prone to both share their feelings and experiences, and to assess the repercussions of the pandemic on their QWL. Lastly, the ALADDIN survey explores a large panel of potential correlates of QWL, using a standard scale (WRQoL).

However, the survey is limited by its cross-sectional design. Further research is therefore needed to assess longitudinal changes in QWL among NSHW throughout the pandemic, and in the long term. Another limitation of our study is the lack of comparative data among day-shift hospital workers. Such data would have helped distinguish between the effects of shift-work by itself on QWL and those related to coping with the pandemic. Future surveys should include both populations of hospital workers. Of note, external factors such as the time of day the questionnaire was completed may have influenced NSHW’s answers (notably due to fatigue). This type of bias, inherent to self-reported data, is difficult to take into account in the analyses. Indeed, a potential “time of the day” effect depends on many unmeasured factors, including NSHW’s number of hours worked before completing the questionnaire, their workload, and inter-individual variations in the internal clock (some individuals feel awake late at night, whilst others are sleepy).

In France, there is a growing interest for healthcare professionals’ quality of life at work, with a national strategy for the improvement of QWL (“Caring the caregivers”), aiming notably at improving work environment and work conditions, informing managers about QWL-related issues and psychosocial risks, and supporting them in the adoption of better work methods [46]. In line with this strategy, a national observatory was created in 2018 to monitor QWL among healthcare and medico-social workers. The COVID-19 pandemic has further stressed the need to document QWL in healthcare services, and to identify its determinants during and after such sanitary crises [47]. Findings from the AP-HP ALADDIN survey contribute to increase the body of knowledge about these key issues, which are central to set up efficient strategies to reinforce healthcare systems. Such strategies should include interventions aiming to improve recognition, reduce stigma related to night-shift work, and to improve information and communication between the different groups of healthcare workers.

To conclude, in this representative survey, insufficient access to screening, information, and protective measures impaired QWL of NSHW after the first wave of COVID-19 in Paris public hospitals. Social and professional recognition of night-shift work appear as key determinants of QWL in this population. Further research is needed to monitor longitudinal changes in QWL of NSHW during and after the different waves of the COVID-19 pandemic.

2 Dec 2021

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Florian Fischer

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For more information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

In your revised cover letter, please address the following prompts:

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: No

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Overview:

The authors evaluated a questionnaire of determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals. The central idea of evaluating the quality of life of night workers during the first wave of COVID is very interesting. Both for the impact on the biological rhythms of night work and for the challenges of working on the front lines during this period of pandemic. The idea is therefore very commendable.

However, the great challenge of this work should be the demonstration with subjective and perhaps objective data, which are the factors that negatively impact the quality of life inherent to night work (eg: factor "x" = night work) plus the factors that coping with the pandemic itself, regardless of the work shift, is also negatively affected (eg factor "y" = COVID pandemic). This distinction is not clearly described and analyzed in this manuscript.

An example: they could also have analyzed the day shift workers in the same period and compared the data. We would have a more accurate view of the “pandemic x work shift” effect.

Minor concerns

The worker's experience in the night shift should be considered and analyzed separately. Workers with less than three weeks on the night scale will not show the same effects perceived as "negative" by workers with one year on the night scale. Likewise, workers with “a lot” of time on the night shift schedule could already be more physically and psychologically tolerant to typical circadian changes and, in many cases, also feeling less of these effects.

Major concerns

The time of day when the questionnaires were answered also influence the results. From a chronobiological point of view, a night shift worker who answered an online questionnaire at 5 pm, after a period of rest, will likely have a different score if the same worker answers the same questionnaire at 5 am, after your work’s turn. This should be described and considered in this manuscript.

All results were described in tables only. Graphic resources with joint presentation as well as correlation data described separately would be essential. All data in tables is overly descriptive and difficult to visualize. It can be confusing for the reader to try to compare data presented at the beginning with data at the end of the table.

History of psychiatric troubles (depression, bipolar disorders) seems to be a factor that directly contributes to the subjective answers (questionnaires) related to quality of life. In this case, it would be interesting for the authors to also present this data separately, considering the presence or absence of this factor in the other results.

Discussion:

The title of the manuscript focuses on the results of workers' recognition during the pandemic as keys to improving quality of life. However, this data (recognition) was mentioned only 4 times in the entire manuscript, and it was not properly discussed.

The feeling of being vulnerable to COVID infection, as well as the fear of transmitting the disease to family members, can be crucial factors in these workers' negative quality of life scores. Still, the sudden change in the organization of work seems to be another impacting factor on quality of life, especially for nurses. These data should be discussed with other results already presented in the literature, when one wants to compare the effects of the pandemic on these professionals, regardless of the work shift.

It would be essential, at least in the discussion, to describe what the literature presented as "quality of life", with these same analysis tools, of workers before the pandemic (control). The work of Gafsou B, et. al, 2021 could have been more discussed. Again, the data were only presented descriptively. What was expected is an intense discussion of each variable.

The authors commented ,"Cultural specificities may also play a role, as shown in other research areas such as perception of happiness" and that the WRQoL scale's norms is a British instrument (UK) and may not be It is possible to compare with the French context, due to cultural differences between countries. However, to assess the QWL the WRQol scale was used. In other hand, was used this same instrument for the population of French workers. Wouldn't that be contradictory and difficult to trust the data presented?

Finally, in order to affirm the effects of the pandemic on shift workers, in addition to the cross-sectional portrait, the authors are enhanced to explore the longitudinal analysis of the data, so that we can comprehensively understand the impacts of this period on this specific population of workers.

Reviewer #2: This paper aimed to document the determinants of quality of working life (QWL) among night-shift healthcare workers (NSHW) in Paris public hospitals after the first-wave of the COVID-19 pandemic. However, there are few issues that were unclear to me and need further clarification, as below:

1. The use of “several department”, “ several unit” are unclear to me. Suggestion for the authors is to explain these variable under footnote.

2. AP-HP is not spelled out in abstract.

3. The significance of this study is not clearly provided.

4. No information is given on the first wave of pandemic? Why the assessment was done after first wave? What is the significance of having this study after first wave?

5. “The ALADDIN cross-sectional survey (15 June 2020 to 15 September 2020) 76 was conducted among NSHW in the 39 hospitals of the Assistance Publique - Hôpitaux de Paris (AP-HP).” How the hospitals are selected? And any inclusion/ exclusion criterias for the selection?

6. What is the response rate? This may lead to information bias when the response rate is too low.

7. Few of the variables, i.e., “physical activity”, “Change in weight since works at night”, “Travel time to work” are unclear to me. What are the operational definitions for these variables. Table 3: 0.7 hours in the travel time means?

8. Page 29, Line 238: “social and professional recognition ” is unclear to me. Please explain.

9. Table 1 is poorly presented.

10. Page 30, Line 283: “The lack of reference values for the WRQoL scale in France also limits the discussion of results.”. What is the importance of having reference values in this study?

11. Page 30, Line 263: “These differences were however of modest magnitude and did not exceed 3 points in QWL scores.” Is 3 points as a cutoff value to determine the difference between groups? Please provide references.

12. Page 31, Line 290: “Findings from the AP-HP ALADDIN survey contribute to increase the body of knowledge about these key issues, which are central to set up efficient strategies to reinforce healthcare systems.” What are the examples of strategies that could be recommended by the authors based on the findings of this study.

13. The findings of Table 2 is poorly discussed.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

11 Feb 2022

Fabienne MARCELLIN

INSERM UMR1252- SESSTIM

Faculté de Médecine

3e étage - Aile bleue

27 boulevard Jean Moulin

13385 Marseille cedex 5 FRANCE

e-mail: fabienne.marcellin@inserm.fr

Marseille, 11 February 2022

To Prof. Florian Fischer, Academic Editor, PLoS One

Dear Editor,

Thank you very much for giving us the opportunity to submit a revised version of our manuscript entitled “Social and professional recognition are key determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals (AP-HP ALADDIN COVID-19 survey)” to PLoS One.

Below, please find detailed responses to the reviewers’ comments.

As requested, we have attached a Microsoft Word version of the revised manuscript that highlights changes made to the original version, and a final unmarked version of the revised manuscript.

In addition, as requested in the second message received from Dr Bendaña (9 February 2022), we have updated our Data Availability Statement.

We hope that this revised version will meet the criteria for publication in PLoS One, and we remain available to make any changes which could further improve our manuscript.

Best regards,

Fabienne MARCELLIN, corresponding author

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: No

We have complemented the discussion of our results, as suggested by the reviewers (please see answers to reviewers’ comments in point 5).

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

We have performed the complementary statistical analyses asked by the reviewers (please see answers to reviewers’ comments in point 5).

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

A data sharing statement has been added in the revised manuscript, as follows:

“DATA SHARING STATEMENT

Data is available upon request to the scientific committee of the ALADDIN survey.”

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

The manuscript has been re-read and copyedited by two native US English speakers.

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Overview:

The authors evaluated a questionnaire of determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals. The central idea of evaluating the quality of life of night workers during the first wave of COVID is very interesting. Both for the impact on the biological rhythms of night work and for the challenges of working on the front lines during this period of pandemic. The idea is therefore very commendable.

We thank the reviewer for this positive feedback.

However, the great challenge of this work should be the demonstration with subjective and perhaps objective data, which are the factors that negatively impact the quality of life inherent to night work (eg: factor "x" = night work) plus the factors that coping with the pandemic itself, regardless of the work shift, is also negatively affected (eg factor "y" = COVID pandemic). This distinction is not clearly described and analyzed in this manuscript.

An example: they could also have analyzed the day shift workers in the same period and compared the data. We would have a more accurate view of the “pandemic x work shift” effect.

We agree with the reviewer concerning the difficulties to distinguish between the effects of shift-work by itself and those related to coping with the pandemic. Our model was adjusted for factors related to each of these two domains (characteristics and organization of work, perceptions, and experience since the beginning of the pandemic), leading to an estimation of each effect independently of the others.

As noted by the reviewer, it would have been interesting to compare the level and correlates of quality of life at work between day-shift workers and night-shift workers. This should be explored in future surveys.

We have noted this as a limitation of our study in the Discussion section of the revised manuscript, as follows:

“Another limitation of our study is the lack of comparative data among day-shift hospital workers. Such data would have helped distinguish between the effects of shift-work by itself on QWL and those related to coping with the pandemic. Future surveys should include both populations of hospital workers.”

Minor concerns

The worker's experience in the night shift should be considered and analyzed separately. Workers with less than three weeks on the night scale will not show the same effects perceived as "negative" by workers with one year on the night scale. Likewise, workers with “a lot” of time on the night shift schedule could already be more physically and psychologically tolerant to typical circadian changes and, in many cases, also feeling less of these effects.

This is an interesting point. We have already described the variable “Seniority as a night-shift worker,” and tested it as a potential correlate of quality of life at work.

As shown by the univariable analyses, it was not significantly associated with the full-scale WRQoL score (coefficient [95% confidence interval: 0.01 [-0.09; 0.11], p=0.811), even if hospital workers’ years of experience with night-shift work varied greatly (mean (standard deviation) of seniority as a night-shift worker: 9 (8.5) years).

We have discussed this point in the revised manuscript, as follows:

“Of note, the number of years in night-shift work (variable “seniority as a night-shift worker (in years)”) was not significantly associated with overall QWL, despite its heterogeneity in our study sample. We hypothesize that seniority may influence one’s night-shift work experience in different ways. For instance, workers with more night-shift work experience may better cope with stress than those with less experience. By contrast, the latter may have been less exposed to changes in the circadian rhythm, resulting in better perceived health.”

Major concerns

The time of day when the questionnaires were answered also influence the results. From a chronobiological point of view, a night shift worker who answered an online questionnaire at 5 pm, after a period of rest, will likely have a different score if the same worker answers the same questionnaire at 5 am, after your work’s turn. This should be described and considered in this manuscript.

In the analyses, it is difficult to take into account the time of day when the questionnaire was filled in. Indeed, the study sample includes individuals with different work schedules (some having permanent night positions, others working alternatively between day and night shift). In addition, we have not collected information on the number of hours worked and the global workload of survey participants prior to completing the questionnaire. A worker completing the questionnaire at 2 a.m. may feel exhausted from a non-stop 4-hour rush, while another may be in good shape, if activity is calm in the department. Inter-individual variations in the internal clock further complexify the interpretation of a possible “time of the day” effect (some people feeling comfortable and awake even late at night, and others feeling sleepy at the same period).

We have added a point in the Discussion section of the revised manuscript, as follows:

“Of note, external factors such as the time of day the questionnaire was completed may have influenced NSHW’s answers (notably due to fatigue). This type of bias, inherent to self-reported data, is difficult to take into account in the analyses. Indeed, a potential “time of the day” effect depends on many unmeasured factors, including NSHW’s number of hours worked before completing the questionnaire, their workload, and inter-individual variations in the internal clock (some individuals feel awake late at night, whilst others are sleepy).”

All results were described in tables only. Graphic resources with joint presentation as well as correlation data described separately would be essential.

We have added a graphical representation of QWL scores using boxplots, as shown below. This enabled us to alleviate data presented in Table 2 (please see revised manuscript).

Figure 1 - Boxplots of quality of working life scores among night-shift healthcare workers according to their professional category (n=1,387, AP-HP ALADDIN survey, Paris public hospitals)

All data in tables is overly descriptive and difficult to visualize. It can be confusing for the reader to try to compare data presented at the beginning with data at the end of the table.

We agree that the presentation of descriptive statistics in Table 1 may be difficult to read due to the high number of lines. Consequently, we have split the data into six different sub-tables, each representing one group of variables (from “Sociodemographic and economic characteristics” to “COVID-related items”). This will facilitate the interpretation of the tables, while keeping information on each variable analyzed available to readers.

In addition, in Table 3, we have deleted information about variables which did not remain in the final multivariable model.

We have also changed double-spacing to 1.5-line spacing in all tables.

History of psychiatric troubles (depression, bipolar disorders) seems to be a factor that directly contributes to the subjective answers (questionnaires) related to quality of life. In this case, it would be interesting for the authors to also present this data separately, considering the presence or absence of this factor in the other results.

The sample size of NSHW with a history of psychiatric troubles was too small in our survey (n=60) to perform a stratified analysis. Indeed, the lack of statistical power and unbalanced distribution of the variable “history of psychiatric troubles” (4.3% “yes” versus 95.7% “no” in the dataset of the multivariable model) do not enable neither the correct identification of QWL correlates nor the comparison of odds ratios between the two groups.

Discussion:

The title of the manuscript focuses on the results of workers' recognition during the pandemic as keys to improving quality of life. However, this data (recognition) was mentioned only 4 times in the entire manuscript, and it was not properly discussed.

We have added a description of variables related to social and professional recognition in the Methods section of the revised manuscript, as follows (Data collection paragraph):

“NSHW’s perceptions regarding their social and professional recognition were assessed using items related to under-estimation of night-shift work by colleagues, loved ones, and patients; perceptions of the importance of night missions and of workload during night; feeling valued by the general population as a NSHW during the pandemic. Most of these items were derived from different stigma scales (Brakel WHV 2006, Berger BE et al. 2001, Golay P et al. 2021)”.

We have also enriched the discussion of workers’ recognition during the pandemic, as follows:

“Professional recognition also includes feeling supported by peers. In the ALADDIN survey, 64.7% of NSHW reported that night-shift work is often or always under-estimated by colleagues working during the day, and this perceived stigma had a significant detrimental effect on QWL. These findings highlight the need to develop interventions to improve communication, sharing of experiences, and support between day-shift and night-shift hospital healthcare workers. Such interventions can reinforce the sense of community among healthcare workers, and have the potential to improve NSHW’s daily experience in the workplace.”

The feeling of being vulnerable to COVID infection, as well as the fear of transmitting the disease to family members, can be crucial factors in these workers' negative quality of life scores. Still, the sudden change in the organization of work seems to be another impacting factor on quality of life, especially for nurses. These data should be discussed with other results already presented in the literature, when one wants to compare the effects of the pandemic on these professionals, regardless of the work shift.

We chose to focus our discussion on variables which were significantly associated with quality of working life in the multivariable model. Fear of getting infected or to transmit the disease to family members, and changes in work organization have not been identified as independent correlates of quality of working life in the final model.

Nevertheless, in the revised Discussion section, we have added information on these variables, as suggested:

“Results from the univariable analyses confirm the detrimental effect on QWL of self-perceived vulnerability to COVID-19 and fear of transmitting the infection to close relatives. Previous research has also shown a negative psychological impact of these two factors among healthcare workers in France (Chene G et al 2021). Interestingly, in ALADDIN, these factors were not identified as independent correlates of QWL in the final multivariable model, maybe because of their correlation with other COVID-related variables such as difficulties to get screened and perceived inadequate and insufficient protective measures. In the same way, changes in work organization since the beginning of the pandemic did not remain in the QWL model after multivariable adjustment.”

It would be essential, at least in the discussion, to describe what the literature presented as "quality of life", with these same analysis tools, of workers before the pandemic (control). The work of Gafsou B, et. al, 2021 could have been more discussed. Again, the data were only presented descriptively. What was expected is an intense discussion of each variable.

To our knowledge, the only previous study which used the WRQoL scale in the French context was of the one by Gafsou et al, which was conducted before the COVID pandemic and can thus be used as a reference.

We have underlined the lack of published data, as follows (Discussion section):

“There is a lack of published studies on QWL conducted among healthcare workers, especially in France. We identified only one recent survey, which was also based on the WRQoL scale (Gafsou et al).”

The authors commented,"Cultural specificities may also play a role, as shown in other research areas such as perception of happiness" and that the WRQoL scale's norms is a British instrument (UK) and may not be It is possible to compare with the French context, due to cultural differences between countries. However, to assess the QWL the WRQol scale was used. In other hand, was used this same instrument for the population of French workers. Wouldn't that be contradictory and difficult to trust the data presented?

The use of the WRQoL scale is justified here, as it is a standard and validated psychometric tool that enables comparisons between past studies conducted in specific subgroups of French healthcare workers (such as anesthesiologists in the work by Gafsou et al.) as well as with future studies assessing QWL (in healthcare contexts or in other professional contexts).

However, comparing the level of QWL between individuals from different countries remains difficult because of differences in people’s work-related representations and expectancies (what we called “cultural specificities”), and differences in environmental factors such as the social and political context. Of note, UK and France share common characteristics, as both are Northern, high-resource countries of the European geographic region.

We have added the following sentences in the discussion of results:

“These specificities may be linked to differences in people’s work-related representations and expectancies. Environmental factors such as the socio-political context in different countries may make international comparisons even more difficult.”

Finally, in order to affirm the effects of the pandemic on shift workers, in addition to the cross-sectional portrait, the authors are enhanced to explore the longitudinal analysis of the data, so that we can comprehensively understand the impacts of this period on this specific population of workers.

Unfortunately, data collected are cross-sectional. Even if a “longitudinal” dimension has been explored in certain items of the questionnaire (such as variables related to changes in work organization since the beginning of the pandemic), future studies are needed to better understand the impact of the COVID period among NSHW, especially in the long term.

We have modified one sentence in the limitations section of the revised manuscript as follows:

“However, the survey is limited by its cross-sectional design. Further research is therefore needed to assess longitudinal changes in QWL among NSHW throughout the pandemic, and in the long term.”

Reviewer #2:

This paper aimed to document the determinants of quality of working life (QWL) among night-shift healthcare workers (NSHW) in Paris public hospitals after the first-wave of the COVID-19 pandemic. However, there are few issues that were unclear to me and need further clarification, as below:

1. The use of “several department”, “several unit” are unclear to me. Suggestion for the authors is to explain these variable under footnote.

The categories “several departments” and “several units” include NSHW assigned to different departments or units (for instance, people working both in adult and pediatric departments).

We have added the following footnote in Table 1b:

2. AP-HP is not spelled out in abstract.

This has been corrected.

3. The significance of this study is not clearly provided.

We have better highlighted the significance of the study at the beginning of the abstract, as follows:

“Documenting the perceptions and experiences of frontline healthcare workers during a sanitary crisis is key to reinforce healthcare systems. We identify the determinants of quality of working life (QWL) among night-shift healthcare workers (NSHW) in public hospitals in Paris shortly after the first-wave of the COVID-19 pandemic.”

4. No information is given on the first wave of pandemic? Why the assessment was done after first wave? What is the significance of having this study after first wave?

In France, the first wave of the COVID-19 pandemic lasted from March to May 2020. The ALADDIN survey was performed shortly after from 15 June to 15 September 2020), which enabled us to reach NSHW after the initial urgent period, once they were less in the heat of the action, more available to answer the survey, and to have a little hindsight to report their perceptions.

We have modified the following sentence of the Methods section:

“One of the main objectives was to document NSHW’s QWL (i.e. perceived quality of life at work) and its correlates shortly after the first wave of the COVID-19 pandemic (March to May 2020), once healthcare workers were more available to participate in the survey.”

5. “The ALADDIN cross-sectional survey (15 June 2020 to 15 September 2020) 76 was conducted among NSHW in the 39 hospitals of the Assistance Publique - Hôpitaux de Paris (AP-HP).” How the hospitals are selected? And any inclusion/ exclusion criterias for the selection?

The survey targeted NSHW in all public hospitals of the Parisian area. It was conducted among all 39 hospitals of the Assistance Publique - Hôpitaux de Paris (AP-HP), with no specific inclusion/exclusion criteria at the level of hospitals.

We have specified this in the Methods section of the revised manuscript, as follows:

“The ALADDIN cross-sectional survey (15 June 2020 to 15 September 2020) was conducted among NSHW in public hospitals in Paris. It included all 39 hospitals of the Assistance Publique - Hôpitaux de Paris (AP-HP).”

6. What is the response rate? This may lead to information bias when the response rate is too low.

The web survey was available to all NSHW of the AP-HP hospitals. The response rate was approximately 11.5% (1387 /12,000), which was close to our initial objective (1200/12,000). Independently of the response rate, it has to be noted that data weighting and calibration enabled us to work on a representative dataset in terms of age, sex, and professional category.

7. Few of the variables, i.e., “physical activity”, “Change in weight since works at night”, “Travel time to work” are unclear to me. What are the operational definitions for these variables. Table 3: 0.7 hours in the travel time means?

Information on physical activity was collected using the following item:

“Do you practice physical activity?”

Similarly, healthcare workers were asked if they perceived their weight to not have changed, increased or decreased since the beginning of night-shift work.

“Travel time to work” relates to the duration of the home-work one-way commute.

We have modified the label of these variables in the tables, as follows:

- “Physical activity” has been changed in “Practice of any physical activity”.

- “Change in weight since works at night” has been changed to “Perception of a change in weight since working at night”.

- “Travel time to work” has been changed to “Travel time to work (home-work one-way commute)”.

0.7 hours of commute means that the NSHW spends nearly three quarters of an hour for a one-way commute. We have converted travel times to minutes in the table.

8. Page 29, Line 238: “social and professional recognition ” is unclear to me. Please explain.

We have added a description of variables related to social and professional recognition in the Methods section of the revised manuscript, as follows (Data collection paragraph):

“NSHW’s perceptions regarding their social and professional recognition were assessed using items related to under-estimation of night-shift work by colleagues, loved ones, and patients; perceptions of the importance of night missions and of workload during the night; and feeling valued by the general population as a NSHW during the pandemic.”

We have also enriched the discussion of workers’ recognition during the pandemic, as follows:

“Professional recognition also includes feeling supported by peers. In the ALADDIN survey, 64.7% of NSHW reported that night-shift work is often or always under-estimated by colleagues working during the day, and this perceived stigma had a significant detrimental effect on QWL. These findings highlight the need to develop interventions to improve communication, sharing of experiences, and support between day-shift and night-shift hospital healthcare workers. Such interventions can reinforce the sense of community among healthcare workers, and have the potential to improve NSHW’s daily experience in the workplace.”

9. Table 1 is poorly presented.

We have made a short description of each group of variables presented in Table 1. A more detailed description would lead to redundancies between text and tables.

Of note, as recommended by Reviewer 1, we have modified Table 1 to improve readability: it has been split into six different sub-tables, each representing a group of variables. This allows a correspondence with paragraphs in the Results section.

10. Page 30, Line 283: “The lack of reference values for the WRQoL scale in France also limits the discussion of results.”. What is the importance of having reference values in this study?

We refer here to the fact that “WRQoL” norms were developed using data collected in UK National Health Services, and not in France. As this point was already raised earlier in the Discussion, we have removed the sentence page 3 line 283.

11. Page 30, Line 263: “These differences were however of modest magnitude and did not exceed 3 points in QWL scores.” Is 3 points as a cutoff value to determine the difference between groups? Please provide references.

To our knowledge, the minimum important difference in WRQoL scores is not documented among healthcare workers. We have added the following sentence in the Discussion:

“Further research is needed to determine if such a magnitude exceeds the minimum important difference for the WRQoL scale.”

12. Page 31, Line 290: “Findings from the AP-HP ALADDIN survey contribute to increase the body of knowledge about these key issues, which are central to set up efficient strategies to reinforce healthcare systems.” What are the examples of strategies that could be recommended by the authors based on the findings of this study.

We have added examples of strategies as follows:

“Such strategies should include interventions aiming to improve recognition, reduce stigma related to night-shift work, and to improve information and communication between the different groups of healthcare workers.”

13. The findings of Table 2 is poorly discussed.

Findings in Table 2 (distribution of QWL scores) are difficult to discuss due to a lack of data in the literature. We have raised this point as follows:

“There is a lack of published studies on QWL conducted among healthcare workers, especially in France. We identified only one recent survey, which was also based on the WRQoL scale (40). QWL level observed in ALADDIN was lower than that found in this recent survey, conducted among 2,040 French anesthesiologists (median [IQR] WRQoL full-scale score: 71 [63-78] versus 77 [66-85]) (40). This difference is likely to be related to the study period, as the latter survey was performed before the beginning of the COVID-19 pandemic (January to June 2019). It may also be related to the diversity of professional categories participating in ALADDIN, presenting different levels of QWL.”

Other results presented in Table 2 (differences in scores associated with each dimension of QWL) are discussed as follows:

“Executives showed both the best overall QWL and higher scores in the “Home-work interface” and “Job and career satisfaction” dimensions of QWL, compared with that of other professional categories. Along with older age, correlated with less domestic responsibilities related to childcare, a longer experience of night-shift work may explain the greater ability of executives to find the right balance between their professional and personal lives. By contrast, executives (together with midwives) presented a low QWL score in the “Stress at work” dimension, revealing higher levels of stress than other professional categories. Interestingly, midwives reported the lowest QWL related to working conditions. Further research should thus be performed to identify midwives’ specific needs and expectations to both improve their QWL and prevent psychosocial risks (42).”

Submitted filename: Response to reviewers 20janv2022.docx

Click here for additional data file.

8 Mar 2022

Social and professional recognition are key determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals (AP-HP ALADDIN COVID-19 survey)

PONE-D-21-27355R1

Dear Dr. Marcellin,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Florian Fischer

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: Yes: YIN CHENG LIM

30 Mar 2022

PONE-D-21-27355R1

Social and professional recognition are key determinants of quality of life at work among night-shift healthcare workers in Paris public hospitals (AP-HP ALADDIN COVID-19 survey)

Dear Dr. Marcellin:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Florian Fischer

Academic Editor

PLOS ONE