Relationship of Walking to Mortality Among US Adults With Diabetes

BACKGROUND: Walking is associated with reduced diabetes incidence, but few studies have examined whether it reduces mortality among those who already have diabetes. OBJECTIVE: To estimate the association between walking and the risk for all-cause and cardiovascular disease (CVD) mortality among persons with diabetes. DESIGN: Prospective cohort study of a representative sample of the US population. SETTING: Interviewer-administered survey in the general community. PARTICIPANTS: We sampled 2896 adults 18 years and older with diabetes as part of the 1990 and 1991 National Health Interview Survey. MAIN OUTCOME MEASURE: All-cause and CVD mortality for 8 years. RESULTS: Compared with inactive individuals, those who walked at least 2 h/wk had a 39% lower all-cause mortality rate (hazard rate ratio HRR, 0.61; 95% confidence interval CI, 0.48-0.78; 2.8% vs 4.4% per year) and a 34% lower CVD mortality rate (HRR, 0.66; 95% CI, 0.45-0.96; 1.4% vs 2.1% per year). We controlled for sex, age, race, body mass index (calculated as weight in kilograms divided by the square of height in meters), smoking, and comorbid conditions. The mortality rates were lowest for persons who walked 3 to 4 h/wk (all-cause mortality HRR, 0.46; 95% CI, 0.29-0.71; CVD mortality HRR, 0.47; 95% CI, 0.24-0.91) and for those who reported that their walking involved moderate increases in heart and breathing rates (all-cause mortality HRR, 0.57; 95% CI, 0.41-0.80; CVD mortality HRR, 0.69; 95% CI, 0.43-1.09). The protective association of physical activity was observed for persons of varying sex, age, race, body mass index, diabetes duration, comorbid conditions, and physical limitations. CONCLUSIONS: Walking was associated with lower mortality across a diverse spectrum of adults with diabetes. One death per year may be preventable for every 61 people who could be persuaded to walk at least 2 h/wk.