Objective: To evaluate the effect of baseline combination of 6 lifestyle factors on all-cause mortality.
Methods: A total of 62,106 Japanese men and women aged 40-79 years were followed for 12.5 years on average. Hazard ratios and 95% confidence intervals (CIs) of all-cause mortality in relation to healthy lifestyle factors (not currently smoking, not heavily drinking, walking 1 h or more per day, sleeping 6.5 to 7.4 h per day, eating green-leafy vegetables almost daily and BMI between 18.5 and 24.9) were calculated from proportional-hazards regression models. We also estimated population-attributable fractions of death to address the impact of potential lifestyle modifications on mortality.
Results: Until 2003, 8497 deaths were observed. Age-adjusted HR of all-cause mortality for the group with 6 healthy lifestyle factors was 0.42 (95% CI: 0.32-0.56) among men and 0.49 (0.39-0.60) among women, respectively, compared with the group with 0-2 healthy lifestyle factors. Even at ages 60-79 years, a healthy lifestyle has a major impact on mortality. Had the subjects achieved even a 1-point increment in their lifestyle scores, death rates of 24.7% among men and 18.5% among women could have been reduced.
Conclusion: We found an inverse association between baseline combination of 6 healthy lifestyle factors and all-cause mortality as well as its impact on preventable fraction of death. Our results also demonstrated that healthy lifestyle behaviors are important even in old age.