Combined impact of healthy lifestyle factors on lifespan: two prospective cohorts

Abstract

Background: The impact of multiple healthy lifestyle factors on survival time is unclear.

Objective: The aim of this study was to examine differences in survival time associated with a healthy lifestyle versus a less healthy lifestyle.

Methods: This study consisted of 33 454 men (Cohort of Swedish Men) and 30 639 women (Swedish Mammography Cohort) aged 45-83 years and free of cancer and cardiovascular disease at baseline. The healthy lifestyle factors included the following: (i) nonsmoking; (ii) physical activity at least 150 min per week; (iii) alcohol consumption of 0-14 drinks per week; (iv) and healthy diet defined as a modified Dietary Approaches to Stop Hypertension Diet score above the median. Cox proportional hazards regression models and Laplace regression were used to estimate, respectively, hazard ratios of all-cause mortality and differences in survival time.

Results: During follow-up from 1998 through 2014, 8630 deaths amongst men and 6730 deaths amongst women were ascertained through linkage to the Swedish Cause of Death Register. Each of the four healthy lifestyle factors was inversely associated with all-cause mortality and increased survival time. Compared with individuals with no or one healthy lifestyle factor, the multivariable hazard ratios of all-cause mortality for individuals with all four health behaviours were 0.47 (95% 95% confidence interval [CI]: 0.44-0.51) in men and 0.39 (95% CI: 0.35-0.44) in women. This corresponded to a difference in survival time of 4.1 (95% CI: 3.6-4.6) years in men and 4.9 (95% CI: 4.3-5.6) years in women.

Conclusion: Adopting healthy lifestyle behaviours may markedly increase lifespan.

Keywords: lifespan; lifestyle; mortality; prospective studies; survival time.