The study was designed to evaluate the prevalence and associated factors of the WRLBP among hairdressers in Mekelle city, Tigray Ethiopia. This study found that the prevalence rate of WRLBP within the past 12 months was (47.5%) which is comparable with studies done in, South Africa, Brazil, Greece and United Kingdom (39%-53%) (20-23). The prevalence was higher compared to the studies conducted in Ibadan Southwest Nigeria, France, and Egypt which were (12.5% -31%) (12, 24, 25). However, it is lower relative to studies done in Taiwan, Nigeria and Addis Ababa, Ethiopia (71.5% - 83%) (11, 13, 26). The difference might be due to differences in sample size, the definition of low back pain, study area, workload and the difference in assessment tools of the studies. Example, The study conducted in Egypt, that reported a low prevalence of LBP (12.5%) was a comparative study with a small sample size among 80 hairdressers and 50 office workers(12). On the other way hairdressers in Addis Ababa, Ethiopia showed more prevalence of LBP(71.5%) than this study(13). It could be due to more sample size or as the participants were from the capital city of the country they might be open enough to report their pain. In general, the high prevalence of LBP among hairdressers might be due to the stress imposed on the lower vertebral structures by working in prolonged bending and twisting in awkward way working posture. This was supported by the study in the USA, on which hairdressers were one of the top 15 high-risk occupations for back pain among 45 major occupations(10).
In this study, the majority of the hairdressers, 72.5% and 45.6% of those with WRLBP reported that LBP affected their working and leisure time activities respectively. The United States Bureau of labor statistics found that 53% reported taking sick leave and 10% of them got a permanent work disability pension as a result of back pain(27). Similarly, studies conducted in Greece cosmologist, UK, and Egypt hairdressers indicate LBP affected carrying out normal activities and absence from work was indicated because of LBP(12, 20, 21). This may show that LBP has a negative impact on the economic, social and productivity of hairdressers.
This study found that hairdressers working on bending and twisting in awkward back posture were more likely to develop WRLBP. This is supported by the study conducted among Egypt and Brazil hairdressers(12, 22). Incorrect body mechanics during tasks such as bending, turning and focusing on the task places stress on the highly mobile lumbosacral part of the spine(23). Bending incorrectly places a mechanical strain on the posterior longitudinal ligament, which results in stress on the facet joints thereby resulting in LBP(23, 28). On the contrary, awkward posture was not significantly associated with the musculoskeletal study conducted in Addis Ababa, Ethiopia(13). This might be due to the difference in hairdressing style in different settings and variation in hairdressers’ awareness towards comfortable body posture when performing tasks and availability of modernized ergonomic tools.
In this study hairdressers who spent more working days in a week (more than 4 days) in hairdressing, activity was more likely to develop WRLBP which is consistent with two studies conducted in Nigeria(11, 25). But not among the Taiwanese hairdressers(26). The possible explanation could be as the number of working days increased, the number of customers or workload exceeds this may expose the hairdressers to the risk factors of LBP repeatedly. The study on which the majority of participants worked more days per week indicated that hours spent working per week correlated significantly (p=0,002) with how participants bent during their tasks, using their backs rather than their hips and knees(29). This may result in muscle fatigue, decrease fitness and increase pain or discomfort in the musculoskeletal system.
Hairdressers who work in the hair washing job category were more likely to develop WRLBP in this study. It might be due to the washing job category more involves the bending and twisting movements of the spine that can lead to mechanical LBP. This is supported by the study from the USA which reported the prevalence of back pain increased as the time spent on repeated strenuous physical activities and the time spent on repeated bending, twisting, or reaching on a typical job is increased(10). On the other way, hairdressing tasks do not significantly affect discomfort in body regions of Taiwanese hairdressers(26). The difference might be the economical difference between the countries which may affect to get the latest and adjustable hairdressing tools.
This study found that hairdressers who used a washing basin with adjustable height were less likely to develop WRLBP or had a preventing role compared to those who were not used. Similarly, the incidence of back pain was significantly lower in those hairdressers who used ergonomically adjusted types of equipment(13, 23). An ergonomically correct washing basin is easily adjustable and maneuverable and allows for easy and regular changes in posture, thereby breaking the chain of a sustained position(23). The possible explanation maybe when the height is adjustable to the height of hairdressers the spine will be in an upright or erect position that could decrease the awkward or uncomfortable posture of the hairdressers. A study on ergonomic analysis of a hair salon revealed that fixed-height chairs and tables could put hairdressers in uncomfortable positions like twisting and bending to reach the different hairdressing materials(28, 29).
Hairdressers who had job stress in this study were more likely to develop WRLBP this is supported by the study conducted among France hairdressers and WHO report, psychosocial factors appear to play a substantial role in the frequency of low back pain(2, 24). Similarly, job stress was one of the psychosocial demands associated with increased risk of LBP(31). It might be those who were stressed in their job had different physical influences and workloads that may affect the occurrence of LBP.
This research addressed one of the major occupational health problems among the neglected group of hairdressing workers. However, as it is a 12-month self-reported pain or discomfort there might be recalled bias, hence there might be over and underestimation of the magnitude of LBP. These could lead to a possible variation in the estimation of association among WRLBP and other variables. It is also a cross-sectional study design, in which the temporal occurrence of LBP outcomes cannot be proved and the study also lacks a comparison group. It is advised in future research projects to analyze in-depth by considering postural assessment and objective measurement of the ergonomic tools.