Men who have smoked or currently smoke are significantly more likely to develop androgenetic alopecia (AGA) than men who have never smoked, according to a new study.

In addition, the odds of developing AGA are higher among those who smoke at least 10 cigarettes per day than among those who smoke less, the study authors found.

“Men who smoke are more likely to develop and experience progression of male pattern hair loss,” lead author Aditya Gupta, MD, PhD, professor of medicine at the University of Toronto, Toronto, and director of clinical research at Mediprobe Research Inc., London, Ontario, Canada, told this news organization.

“Our patients with male pattern baldness need to be educated about the negative effects of smoking, given that this condition can have a profound negative psychological impact on those who suffer from it,” he said.

The study was published online in the Journal of Cosmetic Dermatology.

Analyzing Smoking’s Effects

Smoking generally has been accepted as a risk factor for the development and progression of AGA or the most common form of hair loss. The research evidence on this association has been inconsistent, however, the authors wrote.

The investigators conducted a review and meta-analysis of eight observational studies to understand the links between smoking and AGA. Ever-smokers were defined as current and former smokers.

Overall, based on six studies, men who have ever smoked are 1.8 times more likely (P < .05) to develop AGA.

Based on two studies, men who smoke 10 or more cigarettes daily are about twice as likely (P < .05) to develop AGA than those who smoke up to 10 cigarettes per day.

Based on four studies, ever smoking is associated with 1.3 times higher odds of AGA progressing from mild (ie, Norwood-Hamilton stages I-III) to more severe (stages IV-VII) than among those who have never smoked.

Related Analysis Finds Risk of Alopecia Areata After COVID-19 Infection

Based on two studies, there’s no association between AGA progression and smoking intensity (as defined as smoking up to 20 cigarettes daily vs smoking 20 or more cigarettes per day).

“Though our pooled analysis found no significant association between smoking intensity and severity of male AGA, a positive correlation may exist and be detected through an analysis that is statistically better powered,” said Dr. Gupta.

The investigators noted the limitations of their analysis, such as its reliance on observational studies and its lack of data about nicotine levels, smoking intensity, and smoking cessation among study participants.

Additional studies are needed to better understand the links between smoking and hair loss, said Dr. Gupta, as well as the effects of smoking cessation.

Improving Practice and Research

Commenting on the findings for this news organization, Arash Babadjouni, MD, a dermatologist at Midwestern University, Glendale, Arizona, said, “Smoking is not only a preventable cause of significant systemic disease but also affects the follicular growth cycle and fiber pigmentation. The prevalence of hair loss and premature hair graying is higher in smokers than nonsmokers.”

Dr. Babadjouni, who wasn’t involved with this study, has researched the associations between smoking and hair loss and premature hair graying.

“Evidence of this association can be used to clinically promote smoking cessation and emphasize the consequences of smoking on hair,” he said. “Smoking status should be assessed in patients who are presenting to their dermatologist and physicians alike for evaluation of alopecia and premature hair graying.”