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Studies in Twins Highlight New Risk Factors for Hair Loss
By Brenda Goodman
WebMD Health News
Reviewed by Laura J. Martin, MD
Sept. 23, 2011 -- Hair loss may not just be a matter of age or unlucky genes.
Preliminary findings from new studies of male and female identical twins suggest that a broad range of lifestyle factors, including stress, smoking, heavy drinking, and sun exposure, may also foil the follicles.
That appeared to be especially true for women. One study found that wives who lost a spouse to death or divorce were at highest risk of hair loss at the midline, which leads to a widening part.
In men, genes seemed to be the biggest predictor of balding, though smoking, drinking, stress, and sun exposure also factored in.
Although that may sound discouraging, experts say the research comes with a silver lining: Adopting healthier habits and controlling stress can sometimes help hair come back.
"Part of it is to manage what you can," says Doris Day, MD, a dermatologist at Lenox Hill Hospital in New York City who was not involved in the research. "The sooner you address it, the better your chances of having recovery."
Twins and Hair Loss
For the studies, Bahman Guyuron, MD, a plastic surgeon at Case Western Reserve University in Cleveland, Ohio, recruited 90 male and 98 female identical twins. "Twins are genetically destined to have the same number of hairs," Guyuron says. "And if one has fewer it means that it is related to outside factors."
Each pair was asked to fill out a detailed questionnaire about their lives and habits, and doctors snapped pictures of their scalps to measure any areas of thinning. A panel of experts judged which twins had the most hair.
"What is amazing is how many of these twins have exactly the same behaviors, the same things matching except one or two factors that possibly may contribute to these differences," Guyuron says.
In women, factors related to stress were often predictive of hair loss. The most important of those was marital status. Twins in stable marriages tended to have fuller heads of hair than a sibling who had been divorced or widowed.
Other characteristics that were related to women's hair loss, probably because of associated stress, Guyuron says, were having a higher income, multiple children, or higher blood pressure.
Factors associated with keeping more hair included wearing hats and other sun protection, drinking coffee, and having a stable marriage.
Men and Hair Loss
In men, genetics appeared to account for most balding. It was the single biggest predictor of hair loss along the front of the head.
But it wasn't the only determining factor. Healthy habits like smoking, heavy drinking, outdoor exercise -- a measure of sun exposure, and being sedentary also increased the risk that a male twin would lose more hair than his brother.
Wearing hats for sun protection and having a higher body mass index (BMI), a measure of size that takes into account both height and weight, appeared to protect men against hair loss.
The studies are scheduled to be presented at the 2011 annual meeting of the American Society of Plastic Surgery in Denver, Colo.
Stress, Lifestyle, and Hair
"I would say it's an interesting observation that needs further review," says Wilma Bergfeld, MD, a dermatologist at Cleveland Clinic, in Ohio. The findings have not yet been published in a peer-reviewed journal, where they would be subject to greater scientific scrutiny.
She says it's not surprising that lifestyle plays a role in hair loss.
"Three cells lines have the fastest turnover cell in your body: Your bone marrow, your GI tract, and your hair follicles. Anything that upsets them will have an adverse effect," Bergfeld says.
Other experts who reviewed the studies for WebMD say they reaffirm what doctors have long observed.
"We do see stress hair loss more in women than we do in men," Day says.
"When you look at the underlying issues, divorce, marriage, childbirth, and surgery are up there as the main physiologic stressors that will cause a stress pattern of hair loss," says Day, and the loss typically starts about three months after the traumatic event.
As for lifestyle factors, she says smoking and heavy alcohol drinking are known to be toxic to the skin.
And often, several will occur together to create a perfect storm of tress trouble.
"If you have a stress and you have smoking and drinking on top of it, and drinking enhances smoking effects," she says. "They're not all separate."
These findings will be presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.