OBJECTIVE -Physical activity is associated with a reduced risk of developing diabetes and with reduced mortality among diabetic patients. However, the effects of physical activity on the number of years lived with and without diabetes are unclear. Our aim is to calculate the differences in life expectancy with and without type 2 diabetes associated with different levels of physical activity.
RESEARCH DESIGN AND METHODS -Using data from the Framingham HeartStudy, we constructed multistate life tables starting at age 50 years for men and women. Transition rates by level of physical activity were derived for three transitions: nondiabetic to death, nondiabetic to diabetes, and diabetes to death. We used hazard ratios associated with different physical activity levels after adjustment for age, sex, and potential confounders.RESULTS -For men and women with moderate physical activity, life expectancy without diabetes at age 50 years was 2.3 (95% CI 1.2-3.4) years longer than for subjects in the low physical activity group. For men and women with high physical activity, these differences were 4.2 (2.9 -5.5) and 4.0 (2.8 -5.1) years, respectively. Life expectancy with diabetes was 0.5 (Ϫ1.0 to 0.0) and 0.6 (Ϫ1.1 to Ϫ0.1) years less for moderately active men and women compared with their sedentary counterparts. For high activity, these differences were 0.1 (Ϫ0.7 to 0.5) and 0.2 (Ϫ0.8 to 0.3) years, respectively.CONCLUSIONS -Moderately and highly active people have a longer total life expectancy and live more years free of diabetes than their sedentary counterparts but do not spend more years with diabetes.
Diabetes Care 29:38 -43, 2006T he prevalence of diabetes is increasing dramatically worldwide. In 2000, 171 million people worldwide were affected by diabetes. This number is expected to double by 2030, mainly as a consequence of population aging and urbanization (1). Type 2 diabetes is associated with long-term complications and a high burden of morbidity (2,3). Evidence suggests an inverse association between physical activity and the risk of developing diabetes (4 -11). Physical activity, through improving insulin sensitivity and glycemic control (12)(13)(14), has been associated with reduced total mortality among diabetic patients (15)(16)(17)(18)(19)(20) and the general population (21).However, the effects of physical activity on the number of years lived with and without diabetes are still unclear. Whether, for example, higher levels of physical activity would reduce the number of years lived with diabetes depends on the balance of its effect on the risks of developing diabetes and mortality. For instance, it has been shown that nonsmokers live longer with cardiovascular disease than smokers because their total life expectancy is ϳ8 years longer (22). As policy makers increasingly advocate modification of risk factors with the aim of decreasing population levels of disease and disability (e.g., 23), it will be important to analyze the extent to which this is actually the case. The conundrum is that modification o...