Baldness, prostate cancer linked among black men
Baldness seems to confer a significantly increased risk of prostate cancer upon black men – particularly if they lose their hair before age 60 years.
Different patterns of baldness were also related to different grades of cancer, Charnita Zeigler-Johnson, Ph.D., and her colleagues reported in the March 26 online issue of Cancer, Epidemiology, Biomarkers, and Prevention (Canc. Ep. Biomark. Prev. 2013;22: 589-96).Those with frontal baldness were more than twice as likely to have high-grade and high-stage disease at diagnosis than were those with other hair loss patterns, wrote Dr. Zeigler-Johnson of the University of Pennsylvania, Philadelphia, and her coauthors.
The researchers’ case-control study comprised 318 black patients with prostate cancer and 219 black controls. The subjects were matched for age and other baseline characteristics. However, patients were significantly older than controls (60 vs. 57 years), and more likely to report a family history of prostate cancer (36% vs. 27%). Any form of baldness occurred in significantly more patients than in controls (20% vs.13%).
When the investigators conducted a multivariate analysis, they found a number of significant associations between the cancer and hair loss. Compared with those without hair loss, men with any form of baldness were 69% more likely to have prostate cancer. Frontal baldness was associated with more than a doubling in the risk of both high-stage and high-grade disease (odds ratio, 2.61 and 2.20, respectively).
Men with vertex balding who developed prostate cancer were significantly more likely to present with a low-grade tumor (OR, 1.45).
When the authors broke the groups down by age, they found no significant associations with disease severity among men older than 60 years. Instead, these risks were concentrated in men younger than 60 years. Among these, baldness increased the risk of high-stage cancer by more than three times (OR, 3.43) and more than doubled the risk high-grade disease (OR, 2.33). Frontal baldness was a particularly ominous risk factor for younger men, being associated with more than six times the risk of high-stage disease and more than four times the risk of high-grade disease (OR, 6.51 and 4.23, respectively).
There were also significant relationships observed between baldness and prostate specific antigen levels at diagnosis among younger men. Any baldness was associated with a tripling in the risk of a high PSA (10 ng/mL or more) at diagnosis. The association was stronger for men with frontal-only baldness (OR, 5.29).
The authors speculated that the elevated risks are related to genetically determined androgen metabolism. "There are differences in the prevalence of genotypes that metabolize testosterone and influence dihydrotestosterone (DHT) levels," they wrote. "High DHT levels have been associated with both early pattern baldness and prostate cancer processes, including increases in PSA levels."
In particular, they noted, four genes known to be associated with early-onset baldness are also involved in pathways of androgen metabolism, hair development, and age-related neurodegenerative disease.
"Given the high prevalence of prostate cancer in African Americans, early-onset baldness may be a particularly relevant indicator of risk that deserves attention in future studies as we seek to advance our knowledge about high-risk populations."
None of the authors had any financial disclosures. The work was funded by the Department of Defense and the Public Health Service.
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