LAUSR

Abstract Introduction A protective role of leisure time physical activity with regard to non-communicable chronic diseases (NCDs) is well established. However, shapes of dose-response relationships and the extent of BMI mediation between physical activity and disease risk are not well known. Furthermore, the knowledge about risk reductions from active commuting is limited. Methods Meta-analyses of prospective cohort studies published from January 1990 to June 2019 were conducted, 1) to assess the effect of leisure time and commuting physical activity on cardiovascular disease (CVD), type 2 diabetes, breast cancer and colon cancer, and 2) to quantify the extent to which adjustment for BMI affect these relations. Results Random effect meta-analyses of 59 prospective cohort studies estimated that individuals who engaged in 11.25 MET-hours/week of active commuting had a decreased risk of myocardial infarction (MI) by 18% (95% CI: 1–33%) and type 2 diabetes by 22% (95% CI: 4–37%) compared with non-commuters. Corresponding risk reductions for leisure-time physical activity (LTPA) were 22% for MI, 26% for CVD, 27% for heart failure, 23% for stroke, 22% for type 2 diabetes, 15% for colon cancer and 7% for breast cancer. Except for breast cancer, adjustment for BMI reduced the benefit of physical activity. Conclusion Both active commuting and LTPA are associated with lower risk for NCD. Currently, available data is insufficient to establish detail and reliable dose-response curves.