Male pattern baldness may be an independent risk factor for prostate cancer, according to new research presented at the 107th Annual Scientific Meeting of the American Urological Association (AUA).
"The finding needs to be validated, but if it is, the message is that men who are bald, particularly early in life, probably are at increased risk for developing prostate cancer and therefore should be screened more frequently and perhaps earlier," said senior author Dr Neil Fleshner, from Princess Margaret Hospital in Toronto, Canada.
His study of close to 200 men ages 59 to 70 years old also found that baldness combined with finger length ratio is not a predictor of prostate cancer, as some had thought.
"Androgens play a role in the development of male pattern baldness by stunting hair growth and they also play a role in the growth of prostate cells," Dr Fleshner noted. "The ratio of the lengths of index and ring fingers is also a marker of exposure to androgen, with a low index to ring finger ratio indicating high prenatal androgen action."
Baldness predicts prostate cancer
Retrospective case control studies have demonstrated an association between male pattern baldness and the ratio of the lengths of the index and ring fingers (2D:4D) and prostate cancer. The Canadian researchers aimed to validate these findings in a prospective cohort.
Dr Fleshner and his team prospectively enrolled 196 consecutive patients who were referred to their clinic for prostate biopsy. The median age was 64 years, and PSA was 5.8.
Finger lengths were measured using a digital vernier caliper and male pattern baldness was assessed on a scale of 0-4, with 0 being the least amount of balding and four being the most severe.
On univariate analysis, male pattern baldness was associated with prostate cancer (p for trend = 0.03), but 2D-4D ratio was not.
On multivariate analysis, which took into account male pattern baldness and 2D:4D ratio as well as age, abnormal or normal digital rectal examination, and prostate specific antigen level, male pattern baldness remained a significant predictor of prostate cancer.
The researchers also noted a dose response effect, with more severe balding patterns being more strongly associated with prostate cancer at biopsy.
Screen balding men frequently
For frontal balding, the odds ratio (OR) was 2.0; for mild vortex, the OR was 2.1; for moderate vortex, the OR was 2.5; and for severe vortex, the OR was 2.9.
"Not only should men with male pattern baldness early in life, say in their 20s or 30s, be screened more frequently, the threshold for biopsy in those men should probably be higher than for men who are not bald," Dr Fleshner said.
"This is a novel study that introduces a potential new risk factor for prostate cancer," commented Dr Tobias Kohler, from Southern Illinois University School of Medicine in Springfield, to Reuters Health.
"It is not a modifiable risk factor, but there are many risk factors that are not modifiable that would help with screening. We use tools to help stratify risk, such as family history and PSA level, so this might be another thing we can use in our risk calculators to help patients make informed decisions as to whether to biopsy, whether they are at high risk, and how often they should be screened," Dr Kohler said.
Dr Kohler, who is a member of the AUA Public Media Committee, had also said in a statement that someday, if the current findings are verified, "It is entirely possible that male pattern baldness could be another factor to include in future prediction models."
(Fran Lowry, Reuters Health, May 2012)