No modifying effect of education level on the association between lifestyle behaviors and cardiovascular mortality: the Japan Collaborative Cohort Study

We examined the effect of education level on the association between healthy lifestyle behaviors and cardiovascular mortality in the Japanese population. A total of 42,647 community-based men and women aged 40-79 years were enrolled at baseline (1988-1990), followed through 2009. The components of the healthy lifestyle score included the intake of fruits, fish, and milk; body mass index; exercise; avoidance of smoking; moderate alcohol intake; and moderate sleep duration. During the 19.3 years of follow-up, 8,314 all-cause and 2,377 total cardiovascular mortality cases were noted. Inverse associations were observed between healthy lifestyle scores and total cardiovascular disease (CVD) for both the lower and higher education level groups. Multivariable hazard ratios (95% confidence interval) for CVD mortality from the highest to the lowest healthy lifestyle scores, and the population attributable fraction (95% CIs) without healthy lifestyle scores of 7-8 were 0.51 (0.33-0.52) and 42% (24-58%), and 0.38 (0.27-0.47) and 55% (36-69%) for the higher and lower education levels, respectively. Our findings suggest that the association between higher CVD mortality and lower education level can be explained by the individuals' lower adherence to a healthy lifestyle; hence, lifestyle modification would be beneficial for the prevention of cardiovascular mortality, irrespective of the education level.