Assessment of Work-Related Musculoskeletal Disorder Risk Factors and its Health Implications among Informal Sewing Machine Operators in Nigeria

Abstract

Work-related Musculoskeletal Disorders (WMSDs) are a major health concern with considerable impacts on workers and economy worldwide. Researchers have extensively evaluated different formal work systems including mass-production systems in the garment industry, but literature is sparse on informal work systems of sewing machine operators also called Custom Tailors (CTs) in developing countries. Therefore, this study was designed to ergonomically evaluate custom tailoring work-systems for possible WMSD risk factors. The cross-sectional technique was explored to study the working conditions and the occurrence of self-reported WMSDs among a convenient sample of seventy (38 males and 32 females) Nigerian CTs. A pre-labelled body map with 40 Body Pain Locations (BPLs), questionnaire and direct observations with camcorder and still camera were used for data collection. Multinomial logistic regression was used for the questionnaire and BPL analysis, while Ovako Working-posture Analysis System (OWAS) was used to analyse the CTs’ tasks recorded with the camcorder. The 40 BPLs were grouped into dependent variables Y1-Y4, while the questionnaire responses were grouped into 13 independent pain risk factors X1-X13. Among the CTs, 30, 47, 46 and 21% complained of pains at Y1, Y2, Y3 and Y4, respectively. At 10% significance level, X3, X7 and X12 were significant at Y1; X1, X2, X4 and X6 were significant at Y3, while X2 and X10 were significant at Y4. The OWAS categorised CTs’ postures into 1-3, while none reached category 4 that requires immediate corrective actions for improvement. Nonetheless, motion and still pictures reveal very harmful postures that were repeatedly used in CTs’ various tasks as well as incompatibility of tools with users’ anthropometry. Poor work postures were part of the WMSD risk factors in CTs’ informal work systems. The prevalence of WMSDs in CTs particularly in the neck, lower back, knee, ankle and buttocks among other body parts was established. Hence, the need for ergonomic interventions in the CTs’ informal work-system to reduce costs and increase productivity.