Physical environmental and occupational factors inducing work-related neck and shoulder pains among self-employed tailors of informal sectors in Ethiopia, 2019: results from a community based cross-sectional study

This study employed a cross-sectional design to explore the prevalence and occupation-related factors which induce upper extremity disorders (neck and/or shoulder pains) among self-employed tailors in Gondar city, Northwest Ethiopia, from April to May 2019. The city is one of the tourist destinations in the Amhara National Regional State, Northwest Ethiopia, 747 km from Addis Ababa, the capital of Ethiopia. It is located at latitude 12°36′N and longitude 37°28′E at an elevation of 2133 m above sea level. According to the 2007 Central Statistical Agency (CSA) of Ethiopia, the total population of the town was estimated at 323,900. The city is divided administratively into 12 sub-cities. There have been a total of 1300 tailors in the city during the data collection period.

All self-employed tailors in Gondar city were the source population. Tailors who had worked for at least 12 months prior to the study were eligible for this study, while those witha history of injury, accidents, and pregnant women were excluded as they potentially confound the finding. We estimated the sample size using the single population proportion formula with the assumption of 50% prevalence of neck and/ or shoulder pains (as there was no previous evidence), 95% confidence interval (CI) and a 5% desired precision. After adding a 10% for non-response rate, 422 tailors were sampled using the systematic random sampling technique.

Perceived disability: a pain disability point score of 3–6points [38].

Perceived severity: a pain intensity score of ≥50 or < 3 disability points [38].

Awkward postures (AP): working with the neck bent without support, working with a bent wrist, working with the back bent without support, squatting and kneeling for two or more hours [39].

Repetitive work (RW): work that involve repeating the same motion with less than 30 s or no variation every few seconds for two or more hours per day [39].

Static postures (SP): sitting or standing in a restricted space for two or more hours without changing positions per day [39].

Job satisfaction: generic job satisfaction scales core of 32 or above [40].

Job stress: workplace stress scale score of 21 or above [41].

Body mass index (BMI): Self-report weight in kilograms divided by the square of height in meters (kg/m²) where (BMI = < 18.50 (underweight), BMI = 18.50–24.99 (normal), and BMI = ≥ 25.00 (overweight/obese).

Physical exercise: exercising any kind of sport activity at least two times per week for a duration of 30 min [42].

We employed a face-to-face interviewer- administered data collection technique. A standardized Nordic musculoskeletal questionnaire has been used to measure pains in necks and/ or shoulders [43]. The perceived satisfaction of tailors with their jobs was evaluated using a questionnaire on the 10-item generic job satisfaction scale [40]. The perceived job-related stress of workers was collected using the 8-item workplace stress scale questionnaire [41], whilethe 7-itemVon korff et al. questionnaire [38] was employed to evaluate the perceived severity and disability of pains. All the instruments have been used in previous studies carried out in the context of the country [32, 44]. Socio-demographic information such as gender, age, religion, educational status, marital status, income (as a monthly salary), and work experience was also collected. Factors related to the workplace, including working hours per day (< = 8 and > 8 per day), health and safety training (Yes/No), awkward work posture (working with bent/twist position without support, squatting and kneeling for two or more hours perday (Yes/No)), repetitive work (work that involves repeating same motion with < 30 s for two or more hours per day (Yes/No)), static work (sitting or standing in a restricted space for two or more hours without changing positions per day (Yes/No)), rest break (Yes/No), and physical work environment including adjustable chair designs (Yes/No), and adequacy of light at work (Yes/No) were assessed. Data regarding psychosocial factors, such as job satisfaction and job stress andindividual/behavioral factors such as any kind of physical exercise (Yes/No), frequency of physical exercise (two times and > two times per week for at least 30 min), alcohol use (Yes/No), smoking (Yes/No), and body mass index (a self-report weight in kilograms divided by squared height in meters) have also been gathered.

Due emphasis has been given to the formulation of the data collection instrument. As such, the questionnaire was initially designed in English and translated to ‘Amharic’, the local language and back to English by two independent language experts. Seven trained data collectors (3 occupational health and safety professionals, 2 environmental health officers and 2 health informatics staffs) and two supervisors took part in the data collection. The data collectors and supervisors were adequately trained and oriented on issues related to the clarity of the questionnaire, objectives of the study, confidentiality of information, and voluntary participation (informed consent) of the participants. The principal investigator closely monitored the data collectors and supervisors. A pre-test was also conducted on 5% (19 participants) of the sample in Maksegnit town a week before the actual survey. Based on the pretest, the number of questions and some difficult words were changed.

Epi-info version 7.2.1.0 software program was used for data entry and Statistical Packages for Social Science (SPSS) version 20 software program for analysis. Percentages, frequency distributions and measures of central tendency were used to describe categorical variables. We checked the goodness of model fitness by Hosmer and Lemeshow (p = 0.087). The reliability of the standardized Nordic Musculoskeletal questionnaire was tested (Cronbach’s alpha = 0.82), and the reliability of the instrument was supposed tolerable [25]. The 10-item job satisfaction scale questionnaire was also checked for reliability and a Cronbach’s Alpha of 0.67 was found. Further, the 8-item job stress scale questionnaire was tested (Cronbach’s alpha = 0.81). The reliability of the Von korff et al. questionnaire employed for the assessment of perceived disability and severity of pains was checked (Cronbach’s alpha = 0.72). The instruments were, therefore, tolerable for their consistency in repeating what has been previously measured by the tools. Multicollinearity of the variables was checked by collinearity check using variable inflection factors (VIF < 5). The associations between the dependent and independent variables were examined by a binary logistic regression analysis. Independent variables at < 0.2p-values in the bivariable analysis were exported to a multivariable logistic regression model to further investigate the potential effects of confounders. Finally, we determined thelevel of statistical significance at ≤ 0.05 p-values and ascertained the strength of associations at adjusted odds ratio (AOR) with a confidence interval (CI) of 95%.

In the current study, 419 self-employed tailors were participated with a response rate of 99.3%. The majority, 93.6% (N = 392) of the participants were males. Mean age was 29.23 (standard deviations (SD) ± 7.03) years, and 41.3% of respondents were in the age group of 30–39 years. Nearly one third, 36% (N = 150) of the tailors had completed primary school(1–8), while 9.1% (N = 38) indicated they had technical and vocational trainings. The majority, 52% (N = 218) of the tailors worked for < 5 years and the remaining for > 5 years with a mean of 1.48 (SD ± 0.50) years (Table 1).

Of the participants, 79% (N = 331) described their body mass index (BMI) was normal, while 7.6% (N = 32) and 13.4% (N = 56) reported underweight and overweight, respectively. Out of the respondents, 69.7% (N = 292) of them stated they did not performphysical exercise, whereas 24.8% (N = 104) pointed out they exercised 1–2 and the rest > 3 times a week. Only 28.2% (N = 118) of the interviewees said they drank alcohol. Seventy-eight percent (N = 366) of the tailors showed they did not smoke, whereas 9.5 and 3.1% of them were past and current smokers, respectively. The study also indicated that 34.8% (N = 146) of the participants were chat chewers, of whom 31, 54 and 61% chewed every day, 1–3 times a week and occasionally, respectively. Regarding the psychosocial characteristics of the participants, 76% (N = 319) of them had good, 20.5% (N = 86) fair, and 3.3% (N = 14) poor relationships with their customers. About 37.5%(N = 157) of the tailors indicated they were satisfied and the remaining dissatisfied with their current jobs. More than half, 53.0% (N = 222) of the tailors reported their jobs were stressful.

Table 2 shows the occupational and physical environment-related characteristics of the participants. The majority, 53% (N = 223) of the respondents described they worked for < 8 h a day. With regard to working days per week, 77 % (N = 323) of the respondents delineated they worked for < 7 days a week, and the rest for 7 days. Nearly half, 51.3% (N = 215) illustrated that their activities involved awkward working posture (bending/twisting for more than 2 h) a day. Regarding workplace illumination, 58.9% (N = 247) of the respondents presented there was no adequate light.

This study revealed that the 12 month prevalence of painin either neckor shoulder or both sites was 66.6% (N = 279) [95% CI (62.1, 71.1)], and that of the last 7 days and 30 days was 33.2% (N = 139) [95% CI (28.3, 37.7)] and 42.2% (N = 177) [95% CI (37.5, 47.0)], respectively. Figure 1 represents the prevalence of pains in either neck or shoulder or both during the last 12 months. There was no difference in prevalence between male and female respondents (Pearson’s chi square (X²) = 0.186; p-value = 0.421). The majority, 44.1% (n = 123) of the participants who had neck and/ or shoulder pain was in theage group of 30–39 years. The prevalence of neck and/ or shoulder pain among the participants with < 5 years of employment duration was higher (58.1%) than those with > 5 years of work experience counterparts (X² = 12.20; p-value < 0.0001). Visits to physicians for treatments of neck and/ or shoulder pain was reported by 22.6% (n = 63) of the victims. Sixty-two percent (n = 173) of the pain sufferers perceived their pain was severe, while 51.3% (n = 143) of them described it was a disabling.

About 30.5% (n = 85) of the respondents indicated they had pains for 1–7 days, 23.3% (n = 65) for 8–30 days, 32.0% (n = 89) for over 30 days but not every day, and 14.3% (n = 40) every day during the last 12 months. The study also found that 78.1% (n = 218) of the neck and shoulder pain sustainers were prevented from doing normal work at home or away from home during the last 12 months, of those 22.0% (n = 61), 37.3% (n = 104), 22.6% (n = 63) and 18.3% (n = 51) for 0 days, 1–7 days, 8–30 days and > 30 days, respectively (X² = 15.34;p = 0.0001). Only a few, 17.9% (n = 50) of the participants with neck and/or shoulder pains appeared that they had trainings in safety/ergonomics (X² = 2.96; p = 0.085). Moreover, of neck and/or shoulder pain victims, 57.0% (n = 159) of them said they sat for > 8 h a day and the rest for < 8 h and the difference was significant (X² = 18.03; p = 0.0001). Out of the neck and/or shoulder cases, 74.6% (n = 208) of them reported they did not use rest break at work. The lighting condition at work in relation to those with pain was also assessed and over three fourths (n = 206) said they worked in tailoring shops with no adequate light and the difference was observed to be significant (X² = 76.45; p < 0.0001). The majority (71.3%) of the victims were assessed to be involved in awkward/bending and twisting/ working postures for > 2 h a day with a more remarkable increase in neck and/or shoulder pains than those who worked in such postures for < 2 h a day (X² = 23.04; p < 0.0001).

Age, alcohol, educational level, work experience, lack of rest break, absence of sufficient light at work, working posture, prolonged sitting, and working hours per week were detected significant factors ofneck and/ or shoulder disorders in the bivariable analysis. The multivariable regression analysis showed that work experience, rest break, working posture, prolonged sitting, and absence of sufficient light at work remained significant risk factors for neck and/or shoulder pains.

Self-employed tailors who had worked for < 5 years were 1.92 times more likely to be at risk for neck and/orshoulder pains than their counterparts (> 5 years) [AOR = 1.92; 95% CI (1.11, 3.33)]. Participants who did not use rest breaks were 2.13 times at a higher probability of developing neck and/or shoulder pains than those who did [AOR = 2.13; 95% CI (1.20, 4.22)]. The odds of experiencing neck and/or shoulder pains increased by a factor of 2.60 times among tailors who usually worked in awkward /bending and/or twisting/ postures than those who did not [AOR = 2.60; 95% CI (1.45, 4.47)]. Those who usually worked in tailoring shops with inadequate light were 5.02 times more likely to face neck and/or shoulder pains than those who were engaged in shops with adequate light [AOR = 5.02; 95% CI (3.50, 9.03)]. The multivariable logistic regression analysis also yielded that tailors who usually performed their tasks in a prolonged sitting position were twice more likely to develop neck and/or shoulder pains than those who did not work in such positions [AOR = 2.00; 95% CI (1.20, 3.41)] (Table 3).