The contribution of musculoskeletal disorders and physical workload to socioeconomic inequalities in health.

OBJECTIVES The objective of the study was to examine whether the association of physical workload with musculoskeletal disorders might explain occupational social class inequalities in self-rated health. METHODS Participants of the study were 40-60 years old employees of the City of Helsinki. The data (n = 3740) were derived from several sources, including mail survey designed by the researchers and health check-ups carried out by occupational health care. Prevalence data and logistic regression were used in the analyses. RESULTS An occupational class gradient was found for musculoskeletal disorders. The gradient in musculoskeletal disorders was largely explained by physical demands at work in both genders. The contribution of physical demands to occupational class gradient in self-rated health was considerable in women, but smaller in men. The contribution of musculoskeletal disorder to the occupational class gradient in self-rated health was weak for both genders. CONCLUSION Physical workload is likely to considerably contribute to inequalities in health. Mediation of this effect through musculoskeletal disorder to generic health, however, could not be demonstrated. Different mechanisms are likely to cause inequalities in different health outcomes.