How to live 10 years longer—or more

By Naveed Saleh, MD, MS, for MDLinx
Published April 1, 2019

Key Takeaways

Adopting five low-risk lifestyle factors may be linked to longer life spans in Americans, according to the results of a recent study published in Circulation.

Even though the United States is one of the wealthiest nations, Americans have a shorter life expectancy than other citizens of most of the world’s wealthiest nations. Specifically, Americans rank 31st in terms of global life expectancy for babies born in 2015.

This discrepancy in US life expectancy could be due to the focus of the US healthcare system on drug discovery and treatment rather than prevention. Indeed, preventable cases of cancer and cardiovascular disease are disproportionately prevalent among Americans. Unhealthy lifestyle choices are a major driver of chronic diseases and death in the United States.

A recent meta-analysis including more than half a million subjects from 17 countries with a mean follow-up of about 13 years demonstrated that 60% of premature deaths could be linked to unhealthy lifestyle factors, such as smoking, excessive drinking, physical activity, and poor diet. In the study, a healthy lifestyle was tied to an increase of 7.4-17.9 years in life expectancy in the United States and other wealthy nations. But a detailed analysis of adopting low-risk lifestyle factors to boost life span in Americans has yet to be elucidated.

“Americans could narrow the life-expectancy gap between the United States and other industrialized countries by adopting a healthier lifestyle,” wrote senior author Frank B. Hu, MD, PhD, Departments of Nutrition and Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, and colleagues.

Using data from two major ongoing cohort studies—the Nurses’ Health Study and the Health Professionals Follow-up Study—the investigators quantified the association between lifestyle-related low-risk factors and death. They then defined the following five low-risk lifestyle factors for study: (1) never smoking; (2) body mass index of 18.5-24.9 kg/m2; (3) ≥ 30 min/day of moderate to vigorous physical activity; (4) moderate alcohol intake (5-30 g/day for men and 5-15 g/day for women); (5) and a high diet quality score (upper 40% of Alternate Healthy Eating Index).

They then used National Health and Nutrition Examination Survey (NHANES) data to estimate the distribution of the lifestyle score among the US population, determined age-specific death rates by using the CDC WONDER database, and estimated life expectancy by levels of the lifestyle score via utilizing the life table method.

In total, the researchers recorded 42,167 patient deaths over up to 34 years of follow-up. Multivariable-adjusted hazard ratios for adult mortality with five vs zero low-risk factors were 0.26 (95% CI: 0.22–0.31) for all-cause mortality, 0.35 (95% CI: 0.27–0.45) for cancer mortality, and 0.18 (95% CI: 0.12–0.26) for cardiovascular disease (CVD) mortality. Furthermore, the team found that the population-attributable risk of nonadherence to the five low-risk factors was 60.7% (95% CI: 53.6% to 66.7%) for all-cause mortality, 71.7% (95% CI: 58.1% to 81.0%) for CVD mortality; and 51.7% (95% CI: 37.1% to 62.9%) for cancer mortality.

Life expectancy in patients aged 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 assumed zero low-risk lifestyle factors. Comparatively, for those who adhered to 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.

On average, the projected life expectancy at age 50 years was 14.0 years (95% CI: 11.8–16.2) in US women and 12.2 years (95% CI: 10.1–14.2) in US men who adopted five vs zero low-risk factors.

They also noted that from 1940 to 2014, American life expectancy at birth increased from about 63 years to 79 years. But experts hypothesize that this increase in mortality would be even greater without the widespread frequency of obesity, which serves as a risk factor for heart disease and early death.

Dr. Hu et al found that three-quarters of premature CVD deaths and half of premature cancer deaths among Americans may be secondary to lack of adherence to a low-risk lifestyle. They cited abundant potential for enhancement in health and life expectancy, dependent on individual efforts as well as food, physical, and policy environments.

“Quantifying the association between healthy lifestyle factors and longer life expectancy is important not only for individual behavioral changes but also for health communicators and policy makers,” stated Dr. Hu. “It is critical to put prevention first. Prevention, through diet and lifestyle modifications, has enormous benefits in terms of reducing occurrence of chronic diseases, improving life expectancy as shown in this study, and reducing healthcare costs.”

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