Purpose: The relationship between occupational physical activity (OPA) and mortality has mainly been studied among males and shows conflicting results. This study examines this relationship in a cohort of both male and female workers.
Methods: OPA was determined by 4 self-reported questions in a representative sample of 5,839 Danish workers aged 18-59 years at baseline. A 19-year follow-up on mortality was assessed by linkage with the national death registry. Gender-stratified Cox regression models were used to determine the effect of high OPA on all-cause mortality while controlling for age, BMI, smoking, alcohol consumption, doctor-diagnosed disease, influence at work, and social class.
Results: Two hundred and sixty-two males (8.6%) and 174 females (6.2%) died during follow-up. Being in the highest quartile of OPA predicted an increased risk for all-cause mortality among male workers (HR: 1.79, CI: 1.19-2.70), but not among female workers (HR: 0.99, CI: 0.65-1.49) compared with workers in the lowest quartile of OPA. Among females, indications of a u-shaped relationship between occupational physical activity and all-cause mortality were found.
Conclusions: The findings indicate that high occupational physical activity increases the risk for all-cause mortality among male workers. Future studies need to further examine gender differences in the effects of OPA on mortality.