Researcher Calls Lifestyle, Not Genes, Key to ‘Successful Aging’

Healthy lifestyles and strong relationships have a greater impact on how well people age than heredity does, a researcher said Friday.

“Genes are not destiny,” said Dr. Robert Kahn, coauthor of the book “Successful Aging.” “How well you age, in large part, is up to you.”

Kahn, who is also professor emeritus of psychology and public health at the University of Michigan, made his comments in an interview at the 14th Annual Regional Geriatric Conference, held in Pittsburgh on Friday.

At 81, Kahn follows his own prescription for a long and healthy life. He walks up to five miles a day, visits a gym to lift weights and use a Stairmaster, doesn’t smoke and eats a low-fat diet that includes plenty of grains, fruits and vegetables.

In his own family, there is a history of stroke at about age 50 on his mother’s side, and heart disease before age 60 on his father’s side. “If I thought genetics was everything, I wouldn’t be around,” he said.

His book reviews the results of the MacArthur Foundation Study of Aging in America, which Kahn and other researchers conducted from 1984 to 1997.

The study determined that lifestyle choices and strong interpersonal relationships more than genes determine how well people age.

Although a series of individual tests was conducted, Kahn said the most significant data came from the Swedish twin study. That study compared several hundred sets of twins from Sweden, some of whom were brought up together and some of whom were brought up apart, to determine how much aging was affected by genetics and lifestyle.

“For mental sharpness, it was about 50/50,” he said. “But for physical functioning, it was one-third genetics and two-thirds lifestyle.

“We’re in an era of tremendous genetic research accomplishments, which has been wonderful. But because of that I think we can overestimate the importance of genetics.”

Kahn drew a distinction between “usual aging” and “successful aging.” Most Americans experience usual aging, which follows a pattern of increases in weight, blood pressure and blood sugar, and a decrease in muscular strength.

Kahn said many doctors think the pattern is not a cause for concern or action. “People think it’s caused by some intrinsic process of aging itself, instead of looking at the differences among people and why some age better than others.” Successful aging involves minimizing the risks of disease and disability and maintaining physical and mental functioning, Kahn said. His prescription is a low-fat, low-sugar diet high in grains, fruits and vegetables, exercising at least three times a week for 30 minutes a day, and abstaining from smoking.

Successful aging also relies on a network of close, supportive relationships and staying active.

His prescription applies to all ages. “It’s almost never too late. Nature is very forgiving,” he said.