“Male pattern baldness seems to share pathologic mechanisms with prostate cancer in terms of advancing age, hereditability, and endogenous hormones,” the researchers wrote. “The fact that the age of observable hair loss coincides with the age of microscopic evidence for prostate cancer in autopsy studies, and that male pattern baldness represents cumulative exposures, as opposed to a single serum measurement, may help elucidate prostate cancer etiology.”

To examine the association between male pattern baldness prostate cancerrisk, researchers extracted data for 39,070 men enrolled in the PLCO Cancer Screening Trial, a multicenter, randomized, two-arm study evaluating the effect of cancer screenings on disease-specific mortality.

Participants in this study, who had no cancer diagnosis at baseline, were randomly assigned to a screening group, consisting of annual PSA screeningand digital rectal examination for the first 4 years, or a standard care group. At approximately the time of randomization, the researchers of the present study mailed the participants a sex-specific baseline questionnaire.

Men who continued to be actively followed between 2006 and 2008 also were mailed a supplemental questionnaire to further investigate possible risk factors, asking patients to recall and categorize their hair-loss patterns at age 45 years.

The categories were taken from a modified Norwood-Hamilton scale, and included:

• No baldness;
• Frontal baldness only;
• Frontal plus mild vertex baldness;
• Frontal plus moderate vertex baldness; and
• Frontal plus severe vertex baldness.

The researchers followed the patients for diagnosed cancers and deaths through annual mailed update questionnaires, as well as through linkage to the National Death Index. Medical records were abstracted to confirm cancer diagnoses. The researchers used Cox proportional hazards regression models, with age as the time metric, to estimate HRs and 95% CIs of the association between male pattern baldness and risk for prostate cancer.

 

 

The researchers found that during the median 2.78-year follow-up, 1,138 incident cases of prostate cancer were diagnosed, and 571 of these were aggressive (Gleason score ≥7, and/or clinical stage III or greater).

According to study results, compared with men who exhibited no baldness, men with frontal plus moderate vertex baldness at age 45 years did not have a higher risk for overall (HR=1.19; 95% CI, 0.98-1.45) or nonaggressive (HR=0.97; 95% CI, 0.72-1.3) prostate cancer, but had a significantly increased risk for aggressive prostate cancer (HR=1.39; 95% CI, 1.07-1.8).

“Our study found an increased risk for aggressive prostate cancer only in men with a very specific pattern of hair loss, baldness at the front and moderate hair-thinning on the crown of the head, at the age of 45. But we saw no increased risk for any form of prostate cancer in men with other hair-loss patterns,” researcher Michael B. Cook, PhD, an investigator in the division of cancer epidemiology and genetics at the NCI, said in a press release. “While our data show a strong possibility for a link between the development of baldness and aggressive prostate cancer, it’s too soon to apply these findings to patient care.”