Physical Activity and Risk of Mortality from Heart Failure among Japanese Population

Aim: Reports have shown that physical activity is inversely associated with heart failure risk, but evidence in Asian populations is lacking. We sought to examine the impacts of walking and sports participation on heart failure mortality among a Japanese population. Methods: We involved 36,223 Japanese men and 50,615 women (aged 40-79 years) who completed a self-administered questionnaire between 1988 and 1990. We divided participants into four categories of walking (< 0.5, 0.5, 0.6-1.0, and >= 1 h/day) and sports participation (<1, 1-2, 3-4, and >= 5 h/week) and examined associations with activity and heart failure mortality through 2009. Results: We found inverse associations between physical activity and heart failure mortality. The multivariable hazard ratios (95% confidence intervals) for the highest category of walking time compared with the second-lowest category were 0.76 (0.59-0.99) in men and 0.78 (0.61-0.99) in women, while the ratios for the highest category of sports participation time compared with the second-lowest category were 0.62 (0.41-0.93) in men and 1.09 (0.73-1.65) in women. The lower hazard ratios in the highest categories of walking and sports participation time in men became no longer statistically significant after excluding heart failure deaths for the first 5, 10, and 15 years for walking time and 10 and 15 years for sports participation. However, in women, the low hazard ratios for the highest category >= 1.0 h/day of walking time did not change materially. Conclusions: Physical activity was associated with a lower risk of mortality from heart failure in this Japanese community-based population. The attenuated and nonsignificant association of walking and sports participation with the risk in men after exclusion of first 5-15 years heart failure death was probably due to changes in physical activity and death certificate diagnosis during the follow-up and reverse causation. However, the persistent inverse association between walking and the risk in women suggests a beneficial preventive effect on heart failure.