Combined association of occupational and leisure-time physical activity with all-cause and coronary heart disease mortality among a cohort of men followed-up for 22 years

Objectives Leisure-time physical activity (LTPA) is a well-established protective factor for all-cause mortality and cardiovascular mortality while occupational physical activity (OPA) has shown contradictory results. We examined the association between OPA and all-cause and coronary heart disease (CHD) mortality, and tested its combined effect with LTPA. Methods The CORDIS Study (Cardiovascular Occupational Risk Factor Determination in Israel Study) is a prospective cohort study of industrial workers examined during 1985-1989 and followed-up for 22 years. Data on self-reported OPA and LTPA among 4819 males (20-70 years old) were merged with data on all-cause and CHD mortality obtained from the National Death Registry. Results A higher incidence rate of all-cause mortality and CHD mortality was observed among men who performed moderate-hard OPA compared with those who performed none-mild OPA. Multiple regression analysis based on the Cox proportional hazards model showed that moderate-hard OPA was associated with increased risk of all-cause mortality (HR=1.42, 95% CI 1.16 to 1.74, p<0.001), while LTPA (30 min at least twice a week vs less or none) was associated with reduced risk for all-cause mortality (HR=0.61, 95% CI 0.48 to 0.79, p<0.001), after adjusting for potential confounders, including sociodemographic variables, body mass index, comorbidity and lifestyle habits. Employees who performed moderate-hard OPA and no LTPA had the greatest risk for all-cause mortality and employees who performed none-light OPA and LTPA had the lowest risk. Similar but non-significant trends were observed for the association with CHD mortality. Conclusions Moderate-hard OPA among industrial male workers may be deleterious to health and should not be a substitute to LTPA.