According to Lin-Hui Su, M.D., M.Sc., of the Far Eastern Memorial Hospital, and Tony Hsiu-Hsi Chen, D.D.S., Ph.D., of National Taiwan University, Taipei, the risk for the condition is largely genetic, however some environmental factors may also play a role.
"Androgenetic alopecia, a hereditary androgen-dependent disorder, is characterized by progressive thinning of the scalp hair defined by various patterns," the authors wrote as background information in the article.
"It is the most common type of hair loss in men", they added. The two had surveyed 740 Taiwanese men age 40 to 91 (average age 65) in 2005, where at an in-person interview, information was gathered from the men regarding their smoking habits.
They were also asked about other risk factors for their hair loss and if they were suffering from alopecia, and if so, at what age they began losing their hair. Using clinical classifications, their degree of hair loss was assessed, height and weight were measured and blood samples were taken for analysis. It was found that men increased their risk of hair loss with advancing age, but still had lower risk than the average white men.
"After controlling for age and family history, statistically significant positive associations were noted between moderate or severe androgenetic alopecia and smoking status, current cigarette smoking of 20 cigarettes or more per day and smoking intensity," the authors wrote.
They noted that the relationship between the two could be caused by a number of means. Smoking may destroy hair follicles, damage the papilla that circulate blood and hormones to stimulate hair growth or increase production of the hormone estrogen, which may counter the effects of androgen.
"Patients with early-onset androgenetic alopecia should receive advice early to prevent more advanced progression," the authors conclude.
The report was published in the November issue of Archives of Dermatology, one of the JAMA/Archives journals.