Twins and Aging: How Not to Look Old

It's a question surely as old as vanity itself: How can you look young forever? A forthcoming study in the journal Plastic and Reconstructive Surgery offers one surprising idea: as you age, don't be afraid to put on a few pounds. Fat, it turns out, can significantly smooth out wrinkles and give you a younger-looking face. (Read "Beth Teitell: On Not Looking Old.")

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The Annual Twins Days Festival

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The authors of the new study, a team led by Dr. Bahman Guyuron of Case Western Reserve University in Cleveland, are plastic surgeons who study faces for a living. They analyzed photographs of the faces of 186 pairs of identical twins taken at the Twins Days Festival, a sort of twin-pride event held every summer in (naturally) Twinsburg, Ohio. Because the pairs had identical genetic material, differences in how old they looked could be attributed entirely to their behavioral choices and environment. Guyuron's team had the twins fill out extensive questionnaires about their lives — everything from how many times they had married to whether they regularly used sunscreen. Then a panel of four judges independently estimated the twins' ages by looking at photos taken in Twinsburg. (See pictures from the Annual Twins Days Festival.)

The Guyuron team's most interesting findings had to do with weight. Many of the twin pairs were of similar weight, but differences in how old they looked began to appear when one had a body mass index (BMI) at least four points higher than the twin sibling. For twin pairs under 40, the heavier one looked significantly older. But surprisingly, after 40, that same four-point difference in BMI made the heavier twin look significantly younger. (Read "Aging Gracefully.")

The study's authors theorize that "volume replacement" — that is, fat filling in wrinkles — accounts for the rejuvenated appearance of the over-40 twins. This theory was supported even more dramatically among twins older than 55. For them, having as much as an eight-point-higher BMI than their twin was associated with a younger appearance in the face. (Read "A Brief History of Multiple Births.")

Guyuron doesn't recommend that people gain weight just to look younger, and one limitation of his study is that the Twinsburg photos included only faces. If they had shown the whole body, the judges may have knocked a couple of years off the age estimates of those who had kept a youthful figure — and added a couple of years for those who were well fed in the middle.

The paper also makes clear that, weight aside, healthy living is crucial for keeping a youthful face. The siblings who smoked and didn't wear sunscreen looked significantly older than those who avoided cigarettes and tanning. Those twins who had been divorced also looked older (by about 1.7 years) than the twins who had not. (They also looked older than those who had stayed single, which reinforces a point I made in this article: you are better off staying single than getting into a bad relationship.)

Finally — and this was the cruelest finding — those who had taken antidepressants also looked older than their twins who hadn't. In other words, if the misery of your divorce doesn't age you, your attempt to treat it with Prozac might. Guyuron and his colleagues believe this unjust fact has something to do with the drooping relaxation of facial muscles that antidepressants can cause.

The bottom line is that if you care mostly about a young-looking face, don't smoke, don't spend time in the sun without protection, and try not to get into a bad relationship that will make you depressed. Instead, this summer at the beach, stay inside and have an ice cream. Make it a double scoop.

See pictures of the world's most celebrated senior citizens.

Read "The Year in Medicine 2008: From A to Z."