Relation of Work Stressors and Work-related MSDs among Indian Heavy Vehicle Drivers.

AIMS: The aim of the study was to identify the relation of work stressors and work-related musculoskeletal disorders (WRMSDs) among the heavy vehicle drivers. METHODS AND MATERIAL: The study involved 154 bus drivers and 161 truck drivers of India. A specially designed questionnaire was used to assess the physical and psychosocial work stresses, job diagnostics, driving hazards, physical environment, and WRMSDs. STATISTICAL ANALYSIS USED: The odds ratios (OR) and development percentage of the test measurements were calculated in the descriptive statistics. The binary logistic regression and Pearson correlation test were used for the data analysis.
RESULTS: The results of this study showed that the WRMSDs among the truck drivers were higher than those among the bus drivers. The bus drivers were more likely to develop pain in their arms, while the truck drivers were more likely to suffer from neck, shoulders, legs, lower back, and upper back pain. Results from statistical analysis indicated that age, driving hours, physical fatigue, vehicle design, domestic pressure, and growth opportunities had a significant impact on the development of WRMSDs in the bus drivers. While, in the case of truck drivers, it was found that driving hours, tenure, vibration, physical fatigue, mental overload, and job dissatisfaction were significant.
CONCLUSIONS: The study concludes that the work stressors are associated with different types of MSDs, and the level of MSDs differs significantly between the bus and truck drivers. Copyright:

INTRODUCTION

Work-related musculoskeletal disorders (WRMSDs) are disorders of muscles, nerves, tendons, joints, cartilage, and spinal discs associated with exposure to various risk factors in the workplace.[1] Numerous studies have identified an adverse association between the drivers' health and their job due to a wide range of factors like whole-body vibration exposure, awkward posture, long-term seating, road condition, and MSDs.[23] Drivers having high weight or being aged have higher chances of the prevalence of MSDs.[4]

Work stress has negative effects on drivers' physical and psychological health.[5] MSDs among the bus and truck drivers around the world have emerged as a major health problem. These disorders affect various parts of the body, such as neck, shoulders, upper and lower back, arms, and legs. The symptoms of these disorders are discomfort and pain.[67]

The aim of this study was to identify various aspects of work stressors and explores their relationship with the development of MSDs among the bus and truck drivers as well as the existence of any difference of MSD levels in the two types of drivers.

SUBJECTS AND METHODS

Study design

For this cross-sectional study, a total of 188 bus drivers and 191 truck drivers were invited from selected districts of Haryana and National Capital Region (NCR) to represent the study population [Table 1]. But, for various reasons, 34 bus drivers and 30 truck drivers did not participate. So a total of 315 drivers (154 bus and 161truck) were selected by using a convenience sampling method. The questionnaire was explained to most drivers who were unable to understand the English language in their local dialect. At the start of the study, informed consent was obtained from each subject. Most of the drivers were from low and medium economic backgrounds.

Table 1

Number of subjects and reasons for not participating in the study

Reason	Bus divers		Truck drivers		Total
	n	%	n	%	n	%
Invited drivers	188	100	191	100	379	100
Not available during study	11	5.9	5	2.6	16	4.2
Previous MSDs	13	6.9	9	4.7	22	5.8
Poor response	6	3.2	10	5.2	16	4.2
Reason unknown	4	2.1	6	3.1	10	2.6
Subjects	154	81.9	161	84.3	315	83.1

Study tool

An interviewer-administered questionnaire was specifically designed to collect data from the drivers. The predominance of self-reported MSDs among drivers was assessed by a National Institute for Occupational Safety and Health (NIOSH) checklist.[8] The drivers needed to respond to questions about the severity of pain in the course of recent months, absenteeism or loss of productivity because of pain, their findings about the reason for pain, and the types of medicinal measures used to relieve pain. The severity of pain was measured on a scale of 1–4 (mild, moderate, severe, and intolerable) and productivity loss was measured in terms of limited duties and number of lost working days.

To distinguish the characteristics of work and stressors, a multi-method ergonomic checklist was used.[9] The ergonomics checklist consisted of questions on job characteristics, job diagnostic dimensions, physical and psychosocial job stresses, physical environment hazards, and workplace constraints. The checklist queries were answered on a 5-point Likert scale, where '1' mean strong disagreement with the query and '5' meant strong agreement with the query. The positive indicator of the lack of stress on the subject was a low score. The relative loading of scores for each checkpoint segment was calculated by dividing the actual total score with the maximum total score of the segment. For each of the work stressors, the relative loadings would range from 0 to 1, and each work aspect loading ≥0.5 would be measured as a stressor.[10]

Statistical analysis used

The data collected were examined using SPSS for Windows version 22.0. The odds ratios (OR) and development percentage of the test measurements were calculated in the descriptive statistics. As test measures, the subject group's personal characteristics, physiological and psychosocial stressors were included. To check data normality, the Kolmogorov–Smirnov (K–S) test was used. The data were normally distributed for most factors (P < 0.05) for both the bus and truck drivers. The binary logistic regression was performed using the backward elimination method to determine the effect of work stressors and work characteristics on the generation of MSDs. Using the Pearson correlation test, the relationship between work stressors and MSDs was found. ANOVA was used to compare the responses of the bus and truck drivers to different work stressors. The Cronbach's alpha values of the ergonomics checklists for the bus and truck drivers varied from 0.669 to 0.714, showing modest to acceptable reliability.

Ethical clearance

The study was approved by the Institutional Ethics Committee (IEC), Amity University Noida, India on 01 August 2019.

RESULTS

Table 2 shows the personal characteristics of the drivers selected for analyzing work stressors. The values of average age and driving tenure for the truck drivers were significantly higher (P < 0.02) than for the bus drivers. The truck drivers were more in the habit of tobacco chewing than the bus drivers (P < 0.05). The Bus drivers were more qualified than the truck drivers (P < 0.02).

Table 2

Personal characteristics of the drivers

	Bus Drivers (n=154)	Truck Drivers (n=161)
Age (years)a	35.8±8.3	38.4±8.0
Driving hours/daya	9.4±1.7	9.6±1.4
Driving tenure (years)a	12.5±8	15.1±7.9
Education (>10th)b	59.7	44.1
Marriedb	70.8	71.4
Smokersb	33.8	31.7
Tobacco chewersb	29.9	41.6
Alcohol consumersb	34.4	38’5

aMean±Standard deviation, bPercentage

MSDs among drivers

Figure 1 illustrates that approximately 39.4% of the bus drivers and 42% of the truck drivers reported WRMSDs. The bus drivers were more prone to develop arms pain (24.75%,) as compared to the truck drivers (18.75%). However, the truck drivers were more prone to develop legs pain (24.5%), lower back pain (45.25%), neck pain (24%), shoulder pain (25.25%), and upper back pain (28%) as compared to the bus drivers, which is evident from the percentages, i.e., 17% bus drivers develop legs pain, 41.5% lower back pain, 21.5% neck pain, 24.75% shoulders pain, and 26.75% upper back pain.

Figure 1

Prevalence of MSDs by body part among bus and truck drivers

Personal characteristics and MSDs among drivers

Table 3 illustrates that the bus drivers having age >40 years (P < 0.05) and driving for more than 9h (P < 0.001) had significantly higher chances of developing MSDs, while the truck drivers driving for more than 9h (P < 0.001) and driving tenure more than 15 years (P < 0.05) had significantly higher chances of MSDs. In the case of both bus and truck drivers, education, marital status, smoking, tobacco chewing, and alcohol consumption had no significant impact on MSDs. The truck drivers (OR 4.4) experienced greater productivity loss due to pain caused by the loss of working days. The vibration (OR 2.9, P < 0.005) and driving tenure (OR 3, P < 0.005) for the truck drivers showed higher pain-related significance. Drivers were indifferent to the remedial measures, and there was no clear difference between the two types of drivers about the type of measure used for pain-relieving [Table 4].

Table 3

Association of personal characteristics with MSDs

Characteristics	Bus Drivers			Truck Drivers
	OR	95% CI	P	OR	95% CI	P
Age >40 years (compared against ≤40 years)	7.1	(1.2-41.4)	0.03	4.7	(0.8-26.9)	NS
Driving hours >9 h (compared against ≤9 h)	12.5	(4.7-33.4)	0.00	6.5	(2.3-17.9)	0.00
Driving tenure >15 yr (compared against ≤15 yr)	4.5	(0.5-39.9)	NS	8.5	(1.3-58.3)	0.03
Education >10th (compared against ≤10th)	0.6	(0.2-1.6)	NS	1.0	(0.3-2.7)	NS
Married (compared against non-married)	2.4	(1.0-6.1)	NS	2.3	(0.8-6.1)	NS
Smokers (compared against non-smokers)	0.7	(0.3-1.7)	NS	1.3	(0.4-3.9)	NS
Tobacco chewers (compared against non-tobacco chewers)	1.4	(0.5-3.7)	NS	0.8	(0.3-2.4)	NS
Alcohol consumers (compared against non-alcohol consumers)	1.5	(0.6-4.2)	NS	2.0	(0.7-5.5)	NS

OR=Odds Ratio, 95% CI=95% Confidence Interval, NS=Not Significant

Table 4

Driver’s pain severity, causes of pain and remedial measures

	Bus Drivers	Truck Drivers	OR	95% CI	P
Variable
Paina
Severe	31	38	1.7	(0.1-28.9)	NS
Mild	35	34	4.6	(0.3-62.9)	NS
Productivity loss	31	55	4.4	(2.2-8.7)	0.00
Cause of paina
Posture	41	50	1.4	(0.6-3.2)	NS
Vibration	27	48	2.9	(1.4-5.9)	0.004
Vehicle design	12	13	0.8	(0.3-1.8)	NS
Work environment	11	4	0.4	(0.1-1.5)	NS
Work load and driving duration	44	53	1.3	(0.6-2.7)	NS
Driving tenure	27	47	3.0	(1.5-6.0)	0.002
Personal and other reasons	5	3	0.3	(0.1-1.5)	NS
Remediationsa
Pain killers (self-medication)	26	27	0.0	(0-0.6)	0.02
Medical aid (consult doctor)	12	10	0.0	(0-0.5)	0.015
Balm massage	10	11	0.0	(0-0.8)	0.032
Hot water foot bath	7	9	0.1	(0-0.9)	0.043
Rest	10	12	0.1	(0-1.5)	NS
No remedial measures	36	31	0.1	(0.2-3.8)	NS

OR=Odds Ratio, 95% CI=95% Confidence Interval, NS=Not Significant; aPercentage

Drivers' working characteristics and WRMSDs

The ergonomics checklist revealed the driver's multiple working characteristics. The responses of the drivers to the work stressors are shown in Figure 2. The bus drivers identified workplace design (P < 0.001) as more stressful than the truck drivers, whereas the truck drivers identified job specialization (P < 0.001), skill requirement (P < 0.001), physical work (P < 0.001). MMH (P < 0.001), work posture (P < 0.05), noise (P < 0.01), work environment (P < 0.05), vibration (P < 0.001), driving schedule (P < 0.001), vehicle control (P < 0.05), vehicle characteristics (P < 0.001), growth opportunities (P < 0.001), organizational commitment (P < 0.01), and psychosocial personal aspects (P < 0.001) as significantly stressful.

Figure 2

Responses of bus and truck drivers on work characteristics. Notes: *P < 0.05, **P < 0.01, ***P < 0.001

Relation between driver's psychosocial variables and WRMSDs

More than 12–50% of the drivers complained of physical fatigue. For both the bus (OR 22.8, P < 0.05) and truck drivers (OR 59.2, P < 0.001), physical fatigue was positively associated with MSDs development in one or more body regions [Table 5]. For the bus drivers, there was a positive association between domestic pressure (OR 4.2, P < 0.05) and growth opportunities (OR 19.7, P < 0.001) to develop MSDs. The occurrence of MSDs was significantly affected by mental overload (OR 19.2, P < 0.05), and job dissatisfaction (OR 6.6, P < 0.02) among the truck drivers. The irregular working hours, fear and anxiety, task clarity, job autonomy, and social recognition did not have any significant impact on MSDs generation.

Table 5

Psychosocial variables and MSDs association

	Bus Drivers				Truck Drivers
	%	OR	95% CI	P	%	OR	95% CI	P
Physical fatigue	12	22.8	(1.8-282.4)	0.015	50	59.2	(10.1-346.4)	0.001
Mental overload	36	5.9	(0.8-43.4)	NS	40	19.2	(1.1-330.6)	0.03
Irregular working hours	35	2.5	(0.4-16.3)	NS	47	7.0	(0.4-120.6)	NS
Job dissatisfaction	36	4.8	(0.8-28.9)	NS	44	6.6	(1.4-29.9)	0.01
Fear and anxiety	30	1.2	(0.4-3.7)	NS	38	3.7	(0.7-18.9)	NS
Domestic pressure	42	4.2	(1.3-13.6)	0.015	47	1.6	(0.2-11.7)	NS
Task clarity	38	0.6	(0.2-2.0)	NS	43	2.3	(0.6-8.9)	NS
Job autonomy	36	0.7	(0.2-2.6)	NS	41	1.4	(0.5-38.8)	NS
Growth opportunities	29	19.7	(4.5-86.1)	0	41	0.6	(0.1-2.7)	NS
Social recognition	30	0.6	(0.2-2.0)	NS	40	0.7	(0.2-3.0)	NS

OR=Odd Ratio, 95% CI=95% Confidence Interval

The correlation coefficient for the work stressors and the MSDs generation was calculated. Table 6 shows the coefficients of correlation that are statistically significant. Workplace design (OR 4.7, P < 0.001), work posture (OR 5.7, P < 0.001), noise (OR 4.1, P < 0.05), work environment (OR 8.8, P < 0.001) and vibration (OR 8, P < 0.01) contributed significantly to pain generation among drivers in one or more body regions.

Table 6

Correlation between driver’s work characteristics and MSDs

Work characteristics	Bus Drivers						Truck Drivers
	Arms	Legs	Lower Back	Neck	Shoulder	Upper Back	Arms	Legs	Lower Back	Neck	Shoulder	Upper Back
Job specialization			1
Skill requirement		1	3	1
Physical work			1			1		2	3	2	1
MMH			2			1		2	2	1	1
Workplace design	3	3	3	3	3	3				2
Work posture	3	3	3	3	3	3		2	3		3	3
Noise	3	3	3	2	3	3	3	2	3	3	3	3
Work environment			1					1
Vibration	3	3	3	3	3	3	2	2	3	3	3	3
Driving schedule	3	3	3	3	3	3	2		3	2	3	3
Break schedule	1	3	1	1		1	2		3	1	2	3
Vehicle control									1	1
Vehicle characteristics									3	1		1
Safety measures										1
Job autonomy							2		3	1	3	2
Mental overload	3	3	3	3	3	3	3		3	1	3	3
Growth opportunities	1			3		1
Organizational commitment							1

Correlation Coefficients 1=P<0.05, 2=P<0.01, 3=P<0.001

DISCUSSION

This study indicates that the development of MSDs among the bus and truck drivers are the result of the multiple work stress aspects. Both the bus and truck drivers are engaged with various strenuous activities, which cause musculoskeletal problems in their bodies, thereby leading to the problem of absenteeism and accidents on the roads. These accidents may become very valuable to the government or transport company and disability to the drivers for continuing with their job.

MSDs are the manifestations of the ergonomic hazards and are the main cause of the disability of drivers. WRMSDs are the major medical problems among the drivers in both the industrialized and industrially developing nations. Study by Heinrich[11] showed that the major cause of accidents is the human factor. MSDs showed statistical significance in work duration, age, and BMI.12

Truck drivers reported higher levels of pain in legs, lower back. neck, shoulders, and upper back in comparison to bus drivers in this study. This might be due to the higher levels of physical work (including MMH) performed by the truck drivers and their irregular driving and break schedules. A study by Okunribido also confirms the role of MMH in increasing LBP levels.[13]

Different work stressors are found to play a major role in causing MSDs among the bus and truck drivers. This study indicates a real difference in how the bus and truck drivers behaved with the work stressors. The study proves that psychosocial variables play a role in the difference between the bus and truck drivers. The study has observed that age (>40 years) and driving hours (>9 h) positively affect MSDs among the bus drivers, while driving hours (>9h) and driving tenure (>15 years) positively impact the occurrence of MSDs among the truck drivers. Statistically significant determinants of MSDs related complaints are the age and years of driving profession. MSDs are associated with vibration exposure and poor ergonomics of city bus cabins.[14] Vibrations during driving are responsible for the drivers' cervical herniated discs and upper extremities problems.[15]

Psychosocial stressors are related not only to psychosomatic complaints and symptoms of poor health, but also to acute and chronic MSDs.[16] The relation between work-related psychosocial stressors and individual driver characteristics was also found by Montoro.[17]

As a cause of WRMSDs, the truck drivers are more likely to have mental overload and job dissatisfaction compared to the bus drivers, who are more disturbed by domestic pressure and lack of growth opportunities. Among the bus and truck drivers, the effect of physical fatigue in generating MSDs was also observed. Different adverse health indicators, job stress, and performance problems among professional drivers were associated with fatigue.[18]

The results of the correlation analysis revealed a significant relationship between work characteristics and MSDs, validating that musculoskeletal pain and discomfort are the consequences of the interaction of multiple stressors related with working and physical environment as well as some of the personal characteristics.

Thus, from the study of work stressors, it can be concluded that in order to prevent drivers from musculoskeletal problems and increase their productivity, the concept of identifying work stressors among drivers should be introduced for the benefit of both drivers and the transport industry.

Key Messages

This work will help in identifying the work stressors among the drivers. The study will help in reducing the accidents and MSDs among drivers.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.