Healthy Lifestyle Factors and US Life Expectancies

Study Questions:

Are lifestyle factors associated with premature mortality and life expectancies in the US population?

Methods:

Data from the Nurses’ Health Study (1980–2014; n = 78,865) and the Health Professionals Follow-up Study (1986–2014, n = 44,354) were used for the present analysis. Five lifestyle factors were defined in a total lifestyle score (0-5) as never smoking, body mass index of 18.5-24.9 kg/m2, ≥30 minutes/day of moderate to vigorous physical activity, moderate alcohol intake, and a healthy diet (diet quality score in the upper 40%). Hazard ratios for the association of total lifestyle scores (0-5 scale) with mortality were calculated. Data from the NHANES (National Health and Nutrition Examination Surveys; 2013–2014) were used to estimate the distribution of the lifestyle score in the US population. Data from the US Centers for Disease Control and Prevention WONDER database were used to derive the age-specific death rates of Americans. The life table method was applied to estimate life expectancy by levels of the lifestyle score.

Results:

A total of 42,167 deaths were documented during up to 34 years of follow-up. After adjustment of potential confounders, the hazard ratio (HR) for mortality comparing adults with all five healthy factors to those with zero healthy factors was 0.26 (95% confidence interval [CI], 0.22–0.31) for all-cause mortality. Death due to cancer was also significantly reduced in the group reporting all five healthy lifestyle factors (HR, 0.35; 95% CI, 0.27–0.45). In models examining cardiovascular disease mortality, death rates were 82% lower among those performing all five healthy lifestyle factors (HR, 0.18; 95% CI, 0.12–0.26). The population-attributable risk of nonadherence to five low-risk factors was 60.7% (95% CI, 53.6–66.7) for all-cause mortality, 51.7% (95% CI, 37.1–62.9) for cancer mortality, and 71.7% (95% CI, 58.1–81.0) for cardiovascular disease mortality. The estimated life expectancy at age 50 years was 29.0 years (95% CI, 28.3–29.8) for women and 25.5 years (95% CI, 24.7–26.2) for men who adopted zero low-risk lifestyle factors. In contrast, for those who adopted all five low-risk factors, the projected life expectancy at age 50 years was 43.1 years (95% CI, 41.3–44.9) for women and 37.6 years (95% CI, 35.8–39.4) for men. The projected life expectancy at age 50 years was on average 14.0 years (95% CI, 11.8–16.2) longer among female Americans with five low-risk factors compared with those with zero low-risk factors; for men, the difference was 12.2 years (95% CI, 10.1–14.2).

Conclusions:

The authors concluded that adopting a healthy lifestyle could substantially reduce premature mortality and prolong life expectancies in US adults.

Perspective:

The data from these two large cohorts suggest that lifestyle factors are critical to improving survival rates in US adults; however, the lack of diversity in these cohorts limits current understanding of this analysis for other ethnic and racial groups. It is likely that access to safe places to exercise, healthy foods, and programs to prevent weight gain and smoking would translate into significant improvements in health for all communities and populations.

Clinical Topics: Diabetes and Cardiometabolic Disease, Prevention, Diet, Exercise, Smoking

Keywords: Body Mass Index, Cardiovascular Diseases, Cause of Death, Diet, Exercise, Life Expectancy, Life Style, Mortality, Premature, Neoplasms, Primary Prevention, Risk Factors, Smoking, Survival Rate, Weight Gain


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