Not smoking, drinking moderately, and maintaining a healthy weight can add years of disability-free life, researchers have found.
Their analysis used 1998 to 2012 data from the National Health and Retirement Study of nearly 15,000 Americans aged 50 to 89 years.
The healthier cohort had never smoked cigarettes, were not obese (body mass index between 18.5 and 29.9 kg/m2), and drank alcohol in moderation (fewer than 14 drinks a week for men and fewer than 7 for women). Compared with the entire US population, they had a life expectancy at age 50 years that was 7 years longer and an onset of disability that was delayed by up to 6 years.
Current US life expectancy is 78 years for men and 82 years for women, but for the low-risk group in this study, life expectancies were 85 and 89 years, respectively.
The findings by Neil Mehta, PhD, an assistant professor in the Department of Health Management and Policy at the University of Michigan in Ann Arbor, and Mikko Myrskylä, PhD, director of the Max Planck Institute for Demographic Research, Rostock, Germany, were published online July 19 in Health Affairs.
“The findings indicate the magnitude of health gains that could be achieved if more Americans adopted low-risk behaviors,” they wrote.
Previous research has focused on the health effects of a single behavior, such as smoking or drinking too much alcohol.
“Studying the effects of multiple health behaviors exercised simultaneously provides new insights into levels of health that are achievable without novel life-extending medical technologies,” the authors wrote.
They found a striking difference in the best and worse profiles. Fifty-year-old women who had good behavior on all three key factors lived 12 years longer than women of the same age who had never smoked, were obese, and did not drink moderately. For men, the life expectancy gap between the worst- and best-behaving was just more than 11 years.
Each of the three behavioral risk factors was independently associated with early disability; obesity was the biggest driving factor.
Obese men, on average, became disabled at age 64.9 years, and obese women at age 63.0 years, which were 3 and 6 years earlier, respectively, compared with their nonobese counterparts.
People with all three good behaviors had the longest delay of disability, with men in that group having the first sign of disability at age 72.1 years and women at 75.2 years.
Those who have consistently lived the healthy lifestyle described in the study are in the large minority, however.
“By ages 50–59, nearly 80 percent of US adults have either smoked, been obese, or both—a level that has remained relatively stable since the 1970s,” the authors write.
Fewer people today have ever smoked, but obesity is steadily increasing, which may be offsetting the no-smoking gains, the authors suggest.
The study was not designed to see whether the results would be as positive if people who already had at least one of the risk factors had improved their behavior.
However, the authors write, “We found that people who quit smoking at least ten years before entering the study experienced an exceptionally long disability-free life if they were also at low risk in terms of other behavioral factors. This result is consistent with previous findings that quitting smoking and making other favorable behavioral changes, even late in life, increases longevity.”
The study did not address genetic factors, which may influence both whether a person has a risk factor and whether it will harm them.
This research was supported by the National Institute on Aging and pilot funding from the National Institute of Aging supported the Network on Life Course Health Dynamics and Disparities in 21st Century America. Dr Myrskylä was supported by the European Research Council.
Health Aff. Published online July 19, 2017. Full text
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