Jeanne and Susan (age 61) are twins, but they look about 10 years apart in years. Photo: Department of Plastic Surgery, University Hospitals Case Medical Center

By Joan Kron





For years, the similarities between Jeanne and Susan were uncanny.

Growing up, the identical twin sisters not only were mirror images of each other, but also shared a bunch of preferences and personality quirks. Even now, living 1,000 miles apart -- Jeanne in Ohio, Susan in Florida -- "we'll send identical Christmas cards to our parents and choose the exact same gift wrap," Jeanne says.

But they do have some differences, she adds: "We don't have the same taste in men or in weather." In fact, unlike Jeanne, Susan is a lifelong sun worshipper. In addition, Susan began smoking in her late teens, and although she stopped for six years in her 20s, she averaged a pack and a half a day for 16 years before quitting in her late 30s. Jeanne never smoked.

Over time, it seems, these habits have made a remarkable difference in the way they look. Now, "Susan looks ten years older than I do," Jeanne acknowledges. "In fact, when we meet new people I'll say, 'She's my sister,' but I never say she's my twin."

It may seem odd that two people with the same DNA could look so different, but it's common, according to research published in Plastic and Reconstructive Surgery by Bahman Guyuron, a plastic surgeon in Cleveland, and colleagues at Cleveland's Case Western Reserve University. Contrasting behaviors cause subtle differences in appearance that eventually make one of the pair look older than the other.

And that suggests that all of us -- twins or not -- may have more influence on the way we age than we think.

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Catherine Deneuve has been credited with proclaiming that after a certain age, a woman needs to choose between her face and her behind -- meaning that a lean body can result in a face that appears gaunt and haggard. Indeed, for women over 40, this maxim is true, report Guyuron and his study coauthors, who surveyed and photographed 186 sets of identical twins.

Additional weight fills in and softens wrinkles, making a heavier twin look younger than her sister, Guyuron explains. But for women under 40, the effect turns out to be just the opposite: Extra pounds can obscure youthful features like a smooth jawline and cause facial skin to sag. The weight effect was generally seen when a woman had a body-mass index at least four points higher than her twin. (Each point of body mass is equivalent to five or six pounds of weight, so a four-point difference would be 20 to 24 pounds.)

The longer a woman takes birthcontrol pills or hormone-replacement therapy, and the higher the dose, the more likely she is to look younger. That's partly because estrogen can increase water retention, helping to smooth out the skin. And although estrogen is contraindicated for some women and poses health risks as well as benefits, there is no question that "estrogen improves skin elasticity," Guyuron says.

In one case, a 69-year-old who had used hormone replacement for four years longer than her twin looked three-and-a-third years younger, despite having had more lifetime sun exposure. Taking antidepressants, however, was generally associated with an older appearance. In addition to the aging effect of depressed people's sadder facial expressions, Guyuron says, certain depression-relieving drugs can weaken eye muscles, causing the area to look more droopy. (None of the twins who reported antidepressant use in the study were willing to be identified here.)

Women who didn't drink looked younger than their twins who did. Since the study didn't track the amount or type of alcohol that drinkers consumed, though, it wasn't able to suggest exactly what constitutes too much. Actually, research has shown that resveratrol, a substance found in red-wine grapes, can delay aging, Guyuron points out. But in general, excess alcohol consumption can damage blood vessels in the skin. Also, "the liver plays a major role in the quantity and quality of the collagen fibers within the skin layers," Guyuron says. Translation: Heavy drinking's harm to liver function can cause wrinkles.

Cigarettes may not come with an aging warning, but evidently they should: The longer a woman smokes, the older she looks, with deeper and more plentiful wrinkles and more uneven skin tone. According to the research analysis, every ten years of smoking resulted in a perceived extra 2.5 years of age.

More surprising, divorced women were judged to look an average of 1.7 years older than their married or single twins -- possibly because of higher levels of stress or depression. (Marriage isn't always smooth sailing, but it's not as stressful as divorce.) Inexplicably, though, widows looked two years younger. No differences were found with increasing number of divorces, the researchers report. Guyuron guesses that "after one goes through a very challenging situation once, the second or third experience becomes less troubling and would not take as much toll on the face."

If anyone dismisses the idea that sun exposure speeds up aging, this study may change their minds. The researchers calculated the approximate amount of time each woman had spent in the sun since childhood. The twins' photographs, as shown on these pages, confirm that UV exposure deepens wrinkles and mottles the skin. Sunscreen use, however, minimized or prevented these effects.