Ergonomic assessment of work-related musculoskeletal disorder and its determinants among commercial mini bus drivers and driver assistants (mini bus conductors) in Nigeria

INTRODUCTION: Work-related musculoskeletal disorder (WMSD) is a leading causes of occupational injury and disability among drivers and workers in the transport industry. This study evaluated the ergonomically assessed WMSD and its determinants among Nigerian commercial mini bus drivers (BD) and mini bus conductors (BC) METHOD: A total of 379 participants (BD = 200, BC = 179) were purposively sampled for this exploratory cross-sectional study. Participants’ WMSD and work related variables were respectively assessed using the standardized Nordic questionnaire and a content-validated, Driving Work Station Assessment (DWSA) form. Data were analyzed descriptively and inferentially using chi-square and logistic regression. The level of significance was set at α = 0.05. RESULTS: The participants were aged between 20 and 66 years, with a mean age of 33.26±10.76years (BD = 38.42±10.22years, BC = 27.50±8.13years); most of whom consumed alcohol (84.4%) and experienced severe job stress (73.4%). There was a high prevalence (95.8%; BD = 94.5%, BC = 97.8%) of WMSDs, the lower back (66.8%) and upper back (54.1%) had the highest regional prevalence of WMSD. The BC (BC vs BD) had significantly (p<0.05) higher prevalence of Neck (47.7% vs 21.5%) and upper back (80.4% vs 30.5%) WMSDs. Conversely, the BD (BD vs BC) had significantly (p<0.05) higher prevalence of low-back (85.0% vs 46.4%), knee (25.0% vs 9.5%), elbow (11.5% vs 3.9%), and wrist (10.5% vs 3.4%) WMSD. There was a significant association between WMSD and each of work duration (X(2) = 11.634, p = 0.009), work frequency (X(2) = 8.394, p = 0.039), job dissatisfaction (X2 = 10.620, p = 0.001) and job stress (X(2) = 16.879, p = 0.001). Working beyond 4days/week (OR = 10.019, p = 0.001), job dissatisfaction (OR = 1.990, p = 0.031), constrained working postures (OR = 5.324, p = 0.003) and fatigue (OR = 4.719, p = 0.002) were the predictors of WMSD. CONCLUSION: Job stress, work duration and work frequency, posture and fatigue are important determinants of WMSDs among mini bus drivers and their assistants in Nigeria. Ergonomics training intervention for this population is recommended.