A new study has quantified the benefits of a healthy lifestyle like never before: For the first time, scientists have linked three behaviors—not smoking, maintaining a normal weight, and moderate alcohol consumption—to seven additional years of life.
The research, published in Health Affairs, also found that those additional years are spent mostly in good health and free from disability. The study authors hope their findings will be a wake-up call to Americans, a country in which 80% of people reach their 50s having smoked cigarettes, been obese, or both.
To examine the effects of specific health behaviors on longevity, researchers from the University of Michigan and the Max Planck Institute for Demographic Research in Germany analyzed data from more than 14,000 Americans, ages 50 to 89, who were surveyed about their health and lifestyle every two years.
Overall, men and women in the study had a life expectancy of 77.7 and 81.4 years, respectively. But people who never smoked and had a body mass index less than 30 (the threshold for obesity) tended to live four to five years longer than the general population. Those extra years tended to be healthy ones, too, with few reports of disability or limitations in daily activities like getting out of bed, walking, and eating.
When the researchers factored in people’s alcohol consumption, they found that those who also drank moderately—fewer than 14 drinks a week for men and seven for women—lived seven years longer than the general population, and that those years were mostly disability-free, as well.
In terms of public health, lead author Neil Mehta, assistant professor of health management and policy at the University of Michigan, calls those extra years a “massive benefit.” He says he expected to find differences in life expectancy between groups, but that he was unsure if those extra years would be lived with disability.
“We found that individuals who had a low-risk behavioral profile still lived a number of years disabled before they died, but those disabled years were pushed to older ages,” he says. “That finding has implications not only for individuals and their families, but our health care system as a whole.”
Average life expectancy is the United States is lower than in other wealthy countries, Mehta points out, a fact that’s often attributed to the U.S. health care system. But people who followed these three rules had an average life expectancy even higher than that of the general population of Japan—a country known for its longevity.
Previous research has estimated the impact of single health behaviors on longevity, the researchers say, but this is the first to calculate a cumulative effect of several different health behaviors at once. Smoking, obesity, and excessive alcohol consumption were each linked to shorter life and earlier occurrence of disabilities when analyzed separately, but avoiding all three together was associated with the greatest benefits.
“There is a lot of attention today on medical technologies that can extend our life,” says Mehta. “While investments in these technologies are important, we were interested in knowing how much we could gain by improving behaviors that we already know are very bad for us.”
Mehta says the study should serve as a guide for how to live well into old age. “While most of us want a long life, we probably would like those extra years of life to be healthy and productive,” he says. “Behaviors matter, not only for how long you are going to live but also how healthy you are going to live those years.”