Is the association between healthy lifestyle behaviors and cardiovascular mortality modified by overweight status? The Japan Collaborative Cohort Study.

OBJECTIVE
To examine the modifying effects of overweight status on the association of healthy lifestyle behaviors with cardiovascular mortality in the Japanese population.

METHODS
A community-based, prospective cohort of 18,730 men and 24,216 women aged 40-79 years without a history of cardiovascular disease (CVD) or cancer at baseline (1988-1990) was followed until 2009. Healthy lifestyle behaviors included intake of fruits, fish, and milk; exercise; avoidance of smoking; moderate alcohol intake; and moderate sleep duration.

RESULTS
During the median of 19.3 years of follow-up, there were 2412 deaths from total CVD. Inverse associations between healthy lifestyle scores and mortality from stroke, total CVD, and coronary heart disease (CHD) were observed for non-overweight and overweight (body mass index ≥ 25 kg/m²) individuals, although the association was weaker for overweight individuals. The multivariable hazard ratios (HRs, 95% confidence interval) of mortality from total CVD for the highest (6-7) versus the lowest (0-2) scores were 0.44 (0.37-0.54) for non-overweight and 0.56 (0.39-0.81) for overweight individuals. Especially for CHD mortality, such association was more evident for non-overweight compared to that for overweight individuals.

CONCLUSIONS
Our findings suggest that lifestyle modification may be beneficial in the prevention of cardiovascular mortality for persons who are and are not overweight.