Page last updated: August 16, 2017
The marked effect of lifestyle on mortality

The aim of the present study was to examine differences in the risk of mortality and in survival associated with a healthy lifestyle versus a less healthy lifestyle. The analyses were based on a total of more than 60,000 Swedish men and women who were followed in one of two studies; at baseline, the subjects were aged 45 to 83 years and were free of cancer and cardiovascular disease. The goal was to evaluate the effects of four “healthy” lifestyle factors: (1) nonsmoking; (2) physical activity at least 150 min/week; (3) alcohol consumption of 0–14 drinks/week; and (4) a healthy diet, with the latter defined as a modified Dietary Approaches to Stop Hypertension (DASH) 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.

The authors report: “Compared with individuals with no or one healthy lifestyle factor, the multivariable hazard ratios of all-cause mortality for individuals with all four health behaviors were 0.47 (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.” Forum members considered this to be a well-done study on a large cohort with complete follow-up data on mortality. Notable weaknesses included the fact that never drinkers and consumers of 0 to 14 drinks/week were considered in one group (thus, including lifetime abstainers, ex-drinkers, and current moderate drinkers); these subjects were compared with consumers of >14 drinks/week.

Thus potential differences between abstinence versus light/moderate consumption could not be determined. Further, there were incomplete data on the pattern of drinking, and no data on the type of beverage consumed were reported. Nevertheless, the reduction in mortality for subjects following a healthy lifestyle was impressive: a reduction by half, or more, in the risk of mortality and a 4- to 5-year longer lifespan.

Based on a number of previous studies that evaluated similar lifestyle factors and mortality, the results of this study were not unexpected. Still, they strongly support the remarkable effects on mortality and survival of these lifestyle factors. While not smoking was clearly the factor with the strongest effect on reducing mortality, having a healthy diet, exercising, and consuming light to moderate amounts of alcohol all make additional contributions. This is an important message in that even individuals who may be challenged by genetic or socioeconomic predispositions to earlier demise, adopting certain lifestyle habits can help them reach their greatest potential for a longer and healthier lifespan.

Reference: Larsson SC, Kaluza J, Wolk A. Combined impact of healthy lifestyle factors on lifespan: two prospective cohorts. J Int Med 2017. Pre-publication. Doi: 10.1111.joim.12637.

For the full critique of this paper by members of the International Scientific Forum on Alcohol Research, please click here.

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