Prevalence of low back pain among nurses: predisposing factors and role of work place violence.

BACKGROUND: Ergonomic factors predispose nurses to low back pain (LBP). Few studies have clarified the role of workplace violence in LBP occurrence.
OBJECTIVES: The present study was designed to investigate acute and chronic LBP in Iranian nurses and its association with exposure to physical violence as well as its personal and ergonomic risk factors.
MATERIALS AND METHODS: In this analytic cross sectional study, the rate of acute and chronic LBP and contributing factors were investigated among 1246 nurses using a validated questionnaire. Statistical analysis was performed by chi square, student t-test, and logistic regression, to determine the association between independent variables and LBP.
RESULTS: In total, 1246 nurses, consisting of 576 (46.23%) males and 670 (53.77%) females, were included. The mean age and the mean years of employment were 31.23 ± 5.33 and 16.18 ± 7.05, respectively. Both acute low back pain (ALBP) and chronic low back pain (CLBP) were associated with physical violence experience. Moreover, acute and chronic LBP were predicted by positive past history of LBP as well as two ergonomic factors, frequent bending and frequent carrying of patients.
CONCLUSIONS: Besides a history of low back pain and ergonomic factors, physical violence may be considered a contributing factor for acute low back injuries. Special attention to all personal, occupational, and psychological risk factors is recommended.

1. Background

Healthcare settings represent high rates of work-related illnesses and injuries (1). Based on previous studies, four main health concerns facing healthcare workers (HCWs) include musculoskeletal injuries, mainly low back pain (LBP), workplace violence, shift working, and needle stick injuries (2); although, recently high physical work load and job stress have been added to this list (3). LBP is the main issue affecting the quality of life and work productivity as well as absenteeism pattern and disabilities in nursing (4). Data collected on occupational disorders indicate a high rate of LBP among HCWs. The 12-month prevalence of LBP has been estimated from 15% to 64% in developed countries (5-8) and more than 79% in developing countries (4, 9-12). Data on low back injuries in Iran are sparse. Prevalence of low back injuries among Iranian nursing staff has been estimated over 50% (13), while as a comparison, 37.3% of office workers employed in a hospital developed LBP during one year (14).

In addition to individual and psychosocial variables such as age, gender, physical status, smoking and workplace stress (15, 16), main ergonomic factors that endanger nurses to develop LBP include awkward postures, carrying and repositioning patients, prolonged standing, and working without sufficient breaks (9, 17).

Most popular strategies in management and prevention of LBP in healthcare facilities focus on work-related interventions, often including ergonomic interventions and also exercise, while the role of psychosocial factors, including to violence exposure, has not been fully highlighted in preventive measures (18). Nurses who work in developed countries often participate in periodic regular health surveillance, to assess occupational safety and health. Nevertheless, access to these services in developing countries is often overlooked probably due to low economic resources (19, 20).

Healthcare workplace violence is underestimated (20, 21). According to the National Institute of Occupational Safety and Health (NIOSH), hospitals are a main place of violent events against employees (22). In hospitals, nurses feel intimidated in their worksites more than other employees (23, 24). In Iran, 21.3% of nurses were assaulted during one year (25). In another study, 69% of Iranian nurses were exposed to psychological violence (26). As noted by other authors (27), few studies clarifying the association between LBP and violence exposure. In Iran, a number of studies were conducted regarding common injuries in the nursing environment, including needle stick injuries, musculoskeletal problems, and violent assault.

2. Objectives

The present study was designed to investigate acute and chronic LBP in Iranian nurses and its association with exposure to physical violence in addition to other well-known personal and ergonomic risk factors.

3. Materials and Methods

In this analytical cross-sectional study, rates of acute and chronic LBP, exposure to physical violence, and potential risk factors for LBP among nurses were investigated in 2013. There were 1246 licensed nurses working in an academic hospital in northern Tehran, Iran. The hospital provides general and special medical services for urban and rural populations of the country. All nurses with different types of employment including registered, contractual, part-time, and students were included in the study; census method was used for data collection.

The inclusion criteria included fulltime nursing work (more than 36 hours per week) for at least two years and no experience of LBP at least three months prior to the beginning of the one-year period to assess the prevalence of LBP. Coexisting rheumatologic diseases, history of car accident-related injuries, and long-term sick leaves or any other types of absenteeism were considered as exclusion criteria; 1246 participated in the study.

3.1. Data Collection

The questionnaire consisted of two sections. Section one was specified for personal and demographic characteristics. Section two contained questions about LBP and its risk factors. The latter section was adopted from previous validated questionnaires about work-related musculoskeletal disorders (13).

3.2. Dependent Variables

Outcome measures included the rate of acute low back pain (ALBP) and chronic low back pain (CLBP) during the previous year. ALBP was defined as a pain clinically lasting one to seven days with or without radiculation to lower extremities, originated from lumbar paraspinal area, resulting in sick leave or marked limitation of job productivity. CLBP was defined similar to ALBP, but with at least three months of pain. LBP incidents were extracted from reports of nurses to the occupational physician while filling the questionnaires and the data was recorded in the Occupational Health Office.

3.3. Independent Variables

Baseline demographic characteristics, medical history, lifestyle habits, ergonomic factors, exposure to physical violence, and some characteristics of working environment, were defined as independent factors. Age, sex, marital status, smoking, history of LBP, and engaging in a regular exercise program (more than four days weekly), were considered as demographic and medical variables. Job-related factors were years of employment, weekly working period, and type of ward. Potential ergonomic factors (bending, carrying patients, torso twisting, and prolong standing) were rated as not at all, a little, some, rather much and very much in the questionnaire. In the statistical analysis, the three first rankings and the remaining two were separately merged to form low and high, respectively.

The practical definition of physical violence against nurses as a contributing factor for LBP was as follows: exposure of nurses to physical violence by patients, relatives of patients and/or colleagues in the form of beating, whipping, slapping, stabbing, shooting, pushing, biting, at least once during the past year (25).

3.4. Statistics

Statistical analysis was performed using SPSS v. 18 (SPSS Inc., USA). Chi square, student t-test, and logistic regression were used to determine the association between independent variables and LBP. In logistic regression, as a traditional rule, scientifically-accepted potential risk factors for LBP (acute and chronic) were considered for univariate analysis and those with a P value lower than 0.05 were assessed via a stepwise multivariate logistic regression model.

4. Results

In total, 1246 nurses, 576 (46.23%) males and 670 (53.77%) females, were included. The mean age of participants was 31.23 ± 5.33 years (20 to 61). The mean year of employment was 16.18 ± 7.05 years (2 to 30). The mean working time was 37.49 ± 2.33 hours a week. During the previous year, 374 (30.01%) nurses experienced at least one episode of physical violence by patients (27.65%), their fellows (60.29%), and coworkers (12.06%). In addition, there was no significant difference between the mean age of males and females (P > 0.05).

4.1. Low Back Pain Prevalence

One-year prevalence of ALBP and CLBP were 576 (46.23%) and 364 (29.21%), respectively. The mean ages of ALBP and CLBP groups were 30.37 ± 4.10 and 34.78 ± 2.04 years, respectively (P < 0.05). Night shift schedule did not affect ALBP or CLBP occurrence (P > 0.05) (Table 1). The type of ward was not associated with LBP (P > 0.05).

Table 1.

Individual and Occupational Risk Factors Associated With Low Back Pain Among Nurses [a,b]

Risk factors	ALBP ( n = 576)		CLBP (n = 364)
	No. (%)	P value	No. (%)	P value
Exposure to physical violence		< 0.001		< 0.001
No	355 (40.71)		221 (25.34)
Yes	221 (59.09)		143 (38.23)
Past history of low back pain		< 0.001		< 0.001
No	341 (41.23)		126 (15.20)
Yes	235 (56.22)		238 (57.07)
Age		0.117		0.081
< 30 Years	113 (49.56)		57 (25.00)
30-39 Years	284 (42.20)		163 (24.22)
≥40 Years	179 (51.88)		144 (41.74)
Sex		0.006		0.001
Male	310 (53.82)		217 (37.67)
Female	266 (39.70)		147 (21.94)
Marriage		0.388		0.075
No	157 (44.60)		99 (28.13)
Yes	419 (46.86)		265 (29.64)
Having night shift		0.084		0.072
No	129 (47.42)		87 (31.98)
Yes	447 (45.89)		277 (28.44)
Frequent bending		< 0.001		< 0.001
No	98 (28.65)		50 (14.62)
Yes	478 (52.88)		314 (34.73)
Frequent carrying patients		< 0.001		< 0.001
No	166 (33.33)		86 (17.27)
Yes	410 (54.81)		278(37.16)
Frequent torso twisting		0.001		0.042
No	271 (40.21)		173 (25.67)
Yes	305 (53.32)		191 (33.39)
Frequent prolong standing		0.033		0.017
No	93 (32.75)		51 (17.96)
Yes	483 (50.20)		313 (32.54)
Regular exercise		0.067		0.110
No	275 (45.15)		168 (27.58)
Yes	301 (47.25)		196 (30.77)
Smoking		0.122		0.082
No	521 (46.18)		334 (29.60)
Yes	55 (46.61)		30 (25.42)

a Abbreviations: ALBP; acute low back pain, CLBP; chronic low back pain.

b Data are presented as No. (%).

4.2. Factors Related to Acute Low Back Pain and Chronic Low Back Pain

A series of work-related and personal factors were entered in the univariate analysis. It was shown that exposure to physical violence, frequent bending, carrying patients, torso twisting, and standing, as well as having positive history of LBP and male sex increased the susceptibility to ALBP (P < 0.05). Being married, regular exercise, smoking, and increased age had no significant association with ALBP (P > 0.05). Results for CLBP were nearly the same as ALBP. Ergonomic factors (bending, carrying patients, torso twisting and standing), being married, experience of physical violence, male sex, and history of LBP, created susceptibility to CLBP (P < 0.05), but increased age, smoking, and regular exercise had no association (P > 0.05).

4.3. Logistic Regression

Factors associated with ALBP and CLBP in the first step of analysis were entered in the logistic regression analysis. In this way, the associations between ALBP and bending, carrying patients, torso twisting, standing, gender, history of LBP, and violence exposure, were assessed. For CLBP, the same variables considered for ALBP plus being married were included. Results showed that both ALBP and CLBP were associated with physical violence (odds ratios were 1.869 and 2.736, respectively). Moreover, acute and chronic LBP were predicted by positive past history of LBP and two ergonomic factors, frequent bending (odds ratios of 1.978 and 2.465, respectively) and frequent carrying of patients (odds ratios of 1.685 and 2.513, respectively). Past history of low back pain had the highest odds ratio, followed by exposure to physical violence (3.253 and 4.233 for ALBP and CLBP, respectively) (Tables 2 and 3).

Table 2.

Characteristics That Predicted Acute Low Back Pain Among Nurses

	Odds Ratio	95% Confidence Interval	P value
Physical violence	1.869	1.296-2.696	0.001
Past history of low back pain	3.253	2.219-4.769	< 0.001
Male sex	0.641	0.459-1.895	0.129
Frequent bending	1.978	1.188-3.293	0.009
Frequent carrying	1.685	1.072-2.649	0.024
Frequent twisting	1.210	0.809-1.811	0.354
Frequent prolong standing	1.041	0.623-1.741	0.877

Table 3.

Characteristics That Predicted Chronic Low Back Pain Among Nurses

	Odds Ratio	95% Confidence Interval	P value
Physical violence	2.736	1.381-3.863	< 0.001
Past history of low back pain	4.233	3.499-6.114	< 0.001
Male sex	0.435	0.682-1.273	0.101
Being married	1.237	0.778-1.095	0.110
Frequent bending	2.465	1.289-4.714	0.006
Frequent carrying	2.513	1.454-4.344	0.001
Frequent twisting	0.980	0.607-1.581	0.980
Frequent prolonged standing	0.851	0.447-1.620	0.851

5. Discussion

We demonstrated that along with a past history of LBP and some ergonomic factors, physical violence may be considered a contributing factor for acute low back injuries. Role of physical violence in logistic regression was as high as some ergonomic factors, but a past history of LBP had the most prominent association with both types of LBP. Prior investigations focused on work place conditions and somewhat personal characteristics as important risk factors for LBP in medical staff (16, 28). We also considered these factors in addition to physical violence as an important psychological and somewhat mechanical hazard. Predicting violence as a psychological hazard, one expects great improvement of LBP occurrence by appropriate actions against violent incidents in healthcare settings.

In healthcare, low back injuries have higher frequencies among nurses than other HCWs (10). Comparing to other studies related to developed countries, the present finding about LBP prevalence had similar results. In England, Australia, France and the United States, the 12-month prevalence of LBP was reported between 29% and 59% (4, 9, 10). Meanwhile, in Philippine as a developing country, the one-year prevalence of LBP among nurses was 80% (29). In our study, the occurrence rates of ALBP and CLBP were 46.22% and 29.21%, respectively. On the surface these findings are acceptable, but as there is fear of job loss due to illness, underestimation may mask the real prevalence of LBP (19). Strategies about reporting the symptoms as soon as possible can have great roles in prevention of LBP-related impairments and disabilities, since unfortunately nurses may continue working without adequate rest despite having LBP (19). In some cases, the prevalence of musculoskeletal pain was low in developing countries compared to developed countries. One important explanation in part can be cultural difference in perception of illness and under-reporting (30).

As mentioned, special attention in this study was toward physical violence. Compared to other workplaces various types of occupational violence occur more commonly in health care facilities (31). In Japan a developed country, the one-year prevalence of violence exposure was more than 36% among 11000 healthcare staff (32). Meanwhile, violence in hospitals and clinics is usually under-reported and underestimated (21, 33). Among HCWs, nurses do not feel safe during working due to potential violent attacks (34). Main well-established sequels of violence in workplace are anxiety, depression and posttraumatic stress disorder (PTSD), and regional musculoskeletal pains are less likely to be assessed (35). Results of a longitudinal examination showed that exposure of nurses to physical violence affects somatic pains in different areas, including upper and lower extremities, and causes LBP over a six-month period. Concluding to this findings the authors stated that reducing physical violence incidents can be beneficial for health of nurses (36). In another study, 920 nurses were asked about LBP and experience of physical violence. The results showed that the rate of LBP increased from 40% among non-assaulted nurses to 70% among those assaulted three times or more (27). Our findings showed that physical violence may have an effect on acute and chronic LBP with an odds ratio more than 3.

Generally, the nature of LBP incidents in healthcare settings represents that finding an exact cause is almost always problematic (19). Compared to personal variables such as body mass index, work factors are considered a main risk factor for LBP (37). Patient positioning in addition to multiple awkward positions including bending and torso twisting have been reported to have an association with LBP in nurses (38). The role of awkward postures may even be more than patient lifting and manual transporting (28, 39). In other studies, static position and lifting/carrying the patient were associated with LBP (29). Lifting in-bed patients is a major risk factor of LBP among nurses (9, 10). In a systematic review comprising 89 studies, patient handling had the highest risk, followed by other nursing tasks. Moreover, existence of numerous risk factors as confounders in the role of patient handling, a threshold limit below which the nursing work is considered safe, has not been established (40). One of the challengeable subjects in prevalence studies is response rate, which may affect the results by spontaneous exclusion of some cases. Our response rate was high and as we included all the nurses, the selection bias was minimized (28). In the occupational settings, unhealthy and low fit workers should avoid intense work. Due to this principle, the relationship between high prevalent hazards such as ergonomic factors and LBP may be underestimated (28). As we conducted a cross-sectional research, the results may be affected, although major ergonomic factors in nursing had meaningful associations with LBP.

Self-reporting of dependent (i.e. LBP) and independent variables is another issue to be considered. Although self-reporting has been considered as an original information and recall bias, studies suggested that it was in agreement with clinical history and examination (41, 42). The prevalence rate of LBP did not rise with increasing age and this was not in line with other studies (29). In a number of surveys, the association between aging and LBP has been reported (43, 44). Meanwhile in some reports, LBP incidence in the first five years of employment was high (29). Spine degeneration resulted from aging primarily predisposed individuals to low back problems (12); but in our study, avoiding high risk tasks by older nurses and perhaps enhanced workload for younger respondents probably affected the results.

Our study had some limitations. First, we did not have follow-up, so those with severe pain who left their job were not considered. Moreover, we did not consider subacute (7 to 30 days) and at risk (30 to 90 days) LBPs, because we thought that their chronological aspects were less recalled by nurses; in addition, acute and chronic pains were more prominent for absenteeism and disability, respectively. Second, we did not use a tool to explore the pain severity. Third, professional consequences of LBP (e.g. sick leaves) were not measured. Fourth, we included only physical violence. In our study, verbal abuses and threats were not regarded (27, 36). All types of violence could be considered as psychological hazards and should be noted. Fifth, our results might have been influenced by uncontrolled confounding factors, among which, psychological and life style variables were more dominant (45, 46). Another important factor was inadequate staffing (47, 48), since there is nursing shortage in Iran.

The present study had some advantages. We considered both ChLBP and acute episodes, as this was not performed in similar surveys (16, 28, 29, 49, 50). High response rate and considering violence as a disremembered psychological contributing factor for LBP were other advantages of this study. Our analysis although preliminary, highlighted physical violence as a possible risk factor for LBP among nurses and may exacerbate the effects of ergonomic risk factors.