Analyzing musculoskeletal risk prevalence among workers in developing countries: an analysis of small-scale cast-iron foundries in India

Abstract

Musculoskeletal disorders (MSDs) are the most common health issues around the globe and a major cause of disability among workers. In developing countries, most casting industries fall under Small and Medium Scale Enterprises (SMEs); SMEs lack modern equipment and often intensively rely on manual labor. As processes are mainly labor intensive, workers employed in the metal casting sector are often at risk of MSDs. The main objective of this study is to investigate the exposure of work-related musculoskeletal symptoms prevalent among male workers employed in small scale gray cast-iron foundries of northern India. The techniques used included the Nordic Musculoskeletal Questionnaire (NMQ), anthropometric measures, work postures analysis based on digital human modeling (DHM), Rapid Upper Limb Assessment/RULA and Biomechanics Single Action Analysis/BSAA ergonomic assessment tools. Based on the measured anthropometric variables and work postures attained during various routine tasks, virtual work manikins were created and analyzed using human activity analysis in CATIA V5R20. Subjective assessment revealed that distal upper extremity regions i.e. wrists/hands followed by lower back, neck and shoulders have higher frequency of reported MSDs symptoms. Higher musculoskeletal risk was observed with most of the analyzed work postures, with fettling and Manual Material Handling (MMH) tasks being the most affected. A regression model was developed to predict the L4-L5 spine compression load on the workers’ lumbar regions; a coefficient of determination (R2) value of 0.761 indicates an acceptable model fit (R-value = 0.873). Based on the values of the standardized beta coefficients, findings suggested that trunk angle (β = 0.616), followed by upper arm angle (β = 0.408), were stronger predictors on the dependent variable (i.e. L4-L5 spine compression) than population percentile (β = 0.372), object weight (β = 0.208) and lower arm angle (β = 0.183). The findings suggest that factors like manual work demands, poor work station structure, repetitive actions and awkward postures held for a longer duration may likely be associated with MSDs risk severity. The present study may guide the foundry industrialists in analyzing the mismatch between the workers’ job profiles and redesigning the work station layouts in small scale foundries based on minimizing the risk severity associated with the tasks carried out by staff.