TUESDAY, Dec. 22, 2009 (HealthDay News) -- Smoking, being overweight and not using sunscreen all take an additional toll on sun-damaged skin, a new study of twins shows.
The findings, from researchers at Case Western Reserve Medical School in Cleveland, suggest that "people with the same genetic composition are more likely to have the same sort of sun damage," said Dr. Jonette Keri, an assistant professor of dermatology at University of Miami Miller School of Medicine.
In other words, "if your mom aged poorly, you are going to age poorly," she said.
But while you can't run away from your genes, you can control certain environmental or lifestyle factors to keep your skin looking younger for longer.
The report is published in the December issue of the Archives of Dermatology.
According to the study authors, long-term sun exposure causes physical and structural changes to the skin that damages the skin. But while usual skin aging is characterized by the development of fine wrinkles and skin growths, sun-damaged skin includes more coarsely wrinkled skin, spots of extra pigment or lost pigment and dilated blood vessels on the face.
However, as much as 40 percent of aging-related changes are due to environmental or lifestyle factors, not a person's genetics, the researchers said.
The new study in twins -- who share so much of the same genetic material -- seems to make that clear, one expert said.
"I would think that twins would each have the same response to sun exposure as their sibling," said Dr. Jeffrey Salomon, an assistant clinical professor of plastic surgery at Yale University School of Medicine. He was not involved in the new research.
For the study, Kathryn J. Martires, from Case Western, and her colleagues collected data on 65 pairs of twins (both identical and fraternal) who attended the 2002 annual Twin Days Festival in Twinsburg, Ohio.
Martires's team asked each participant about skin type, history of skin cancer, smoking, drinking habits and weight.
Skin damage was similar among the twins whether they were identical of fraternal, the researchers found. But factors outside of genes appeared highly linked with increased skin damage. These included a history of skin cancer, heavier weight and smoking. Drinking was associated with having less skin damage, Martires's group noted.
The overweight-wrinkle connection isn't so obvious, Keri said. Often, weight makes people look older but it can also hide skin damage as the weight fills out their face. "They won't look as wrinkly because the fat on their face is plumping out their skin," she said.
Salomon was surprised by one finding: that the skin cancer rate among the twins was found to be higher than it is in the general population.
"This study, with an 8 percent skin cancer rate in twins, seems high when the general population has an incidence of less than 0.5 percent. This in of itself would merit further examination to look at other [potential risk] factors, such as prenatal x-rays, prenatal sonograms and low birth weights," he noted.
Martires's team hopes people will use the findings from this study to change their own behaviors and prevent excessive skin damage from controllable environmental factors.
"The Twins Days Festival provides a rare opportunity to study a large number of twin pairs to control for genetic susceptibility," the authors wrote. "The relationships found between smoking, weight, sunscreen use, skin cancer and photodamage in these twin pairs may help to motivate the reduction of risky behaviors."
For more information on skin damage from the sun, visit the U.S. National Library of Medicine.