Physical activity and cardiovascular disease in Japan: the Jichi Medical School Cohort Study.

BACKGROUND

Many studies have reported an association between physical activity and cardiovascular disease (CVD); however, the effect of physical activity remains controversial. Few such studies have been conducted in Japan. Therefore, we examined the relationship between physical activity and death from CVD using prospective data from a Japanese population.

METHODS

From a prospective cohort study that comprised 12 490 participants, data from 9810 were analyzed. From April 1992 through July 1995, a baseline survey was conducted in 12 communities in Japan. The participants were followed up until December 2005. Physical activity was assessed using the physical activity index (PAI). PAI scores were grouped in quartiles: Q1 was the lowest PAI quartile and Q4 was the highest. Hazard ratios (HRs) for death from CVD, stroke, and myocardial infarction (MI) were calculated for all PAI quartiles.

RESULTS

The mean follow-up period was 11.9 years, during which time 194 participants died of CVD. With Q1 as the reference, the HRs for death from CVD in Q2, Q3, and Q4, were 0.62 (95% confidence interval, 0.40-0.98), 0.53 (0.31-0.88), and 0.40 (0.22-0.73), respectively, in men, and 0.71 (0.38-1.32), 0.52 (0.26-1.04), and 0.48 (0.22-1.05), respectively, in women. The HRs for death from CVD subtypes were similar but not statistically significant.

CONCLUSIONS

Among a Japanese population, physical activity was associated with a decreased risk of death from CVD. However, more evidence is needed to elucidate the relationships between physical activity and CVD subtypes.