Physical activity and all-cause mortality across levels of overall and abdominal adiposity in European men and women

Background: The higher risk of death resulting from excess adiposity may be attenuated by physical activity (PA). However, the theoretical number of deaths reduced by eliminating physical inactivity compared with overall and abdominal obesity remains unclear. Objective: We examined whether overall and abdominal adiposity modified the association between PA and all-cause mortality and estimated the population attributable fraction (PAF) and the years of life gained for these exposures. Results: Significant interactions were observed, so HRs were estimated within BMI and WC (Height, weight, and waist circumference) strata. The hazards of all-cause mortality were reduced by 16-30% in moderately inactive individuals compared with those categorized as inactive in different strata of BMI and WC. Avoiding all inactivity would theoretically reduce all-cause mortality by 7.35%. Corresponding estimates for avoiding obesity were 3.66%. The estimates for avoiding high WC were similar to those for physical inactivity. Conclusion: The greatest reductions in mortality risk were observed between the 2 lowest activity groups across levels of general and abdominal adiposity, which suggests that efforts to encourage even small increases in activity in inactive individuals may be beneficial to public health.