The Combined Effect of Leisure-Time Physical Activity and Diabetes on Cardiovascular Mortality: The Nord-Trøndelag Health (HUNT) cohort study, Norway

OBJECTIVE: To examine if leisure-time physical activity could cancel out the adverse effect of diabetes on cardiovascular mortality. RESEARCH DESIGN AND METHODS: This study prospectively examined the combined effect of clinical diabetes and reported leisure-time physical activity on cardiovascular mortality. Data on 53,587 Norwegian men and women participating in the population-based Nord-Trøndelag Health (HUNT) Study (1995–1997) were linked with the Cause of Death Registry at Statistics Norway. RESULTS: Overall, 1,716 people died of cardiovascular disease during follow-up through 2008. Compared with the reference group of 3,077 physically inactive people without diabetes, 121 inactive people with diabetes had an adjusted hazard ratio (HR) of 2.81 (95% CI 1.93–4.07). The HR (95% CI) among people who reported ≥3 h of light activity per week was 0.89 (0.48–1.63) if they had diabetes (n = 403) and 0.78 (0.63–0.96) if they did not (n = 17,714). Analyses stratified by total activity level showed a gradually weaker association of diabetes with mortality with increasing activity level (P(interaction) = 0.003). CONCLUSIONS: The data suggest that even modest physical activity may cancel out the adverse impact of diabetes on cardiovascular mortality.