Heavy load carrying and musculoskeletal health: An exploratory study of biomechanical risk factors among sand miners in Pokhara, Kaski District, Nepal

Abstract

Background: Trends in urbanization contribute to the growing global demand for raw construction materials. The health effects of load carrying among occupational groups that mine and carry sand and stone used for construction of roads and buildings remains poorly understood. Methods: We conducted an exploratory cross-sectional study among a convenience sample of sand miners working at an excavation site on the Seti River in Pokhara, Nepal. Load carrying weight, duration, and frequency were used to categorize miners as having “low” or “high” load-carrying exposures. Musculoskeletal disorders (MSDs) were identified using self-reported symptoms of moderate to severe musculoskeletal pain, as well as physical examinations. Results: The average loads carried by female and male sand miners weighed 66 kg and 87 kg, respectively. Among all participants (N = 42), 45% reported moderate to severe musculoskeletal pain in at least one body region and 16 (38%) had MSDs identified using specified case criteria. The prevalence of MSDs was lower among miners carrying, on average, heavier loads compared to those carrying lighter loads (OR = 0.18; 95% CI: 0.04, 0.7), possibly indicative of the healthy worker survival effect. Miners carrying loads for longer durations had higher odds of MSDs compared with those carrying for shorter durations. Conclusion: This study has provided data on the extraordinary loads carried by sand miners in Nepal and preliminary evidence of health impacts associated with these loads. However, larger epidemiologic studies are needed to justify action to protect the health and safety of these unrecognized and understudied groups.