Michael Cook

NCI, DCEG, HREB

PLCO (Learn more about this study)

2011-0231

Oct 6, 2011

Male pattern baldness and prostate cancer risk: a prospective study in PLCO

Prostate cancer and male pattern baldness are both influenced by androgens. Finasteride, a 5-alpha reductase inhibitor that blocks the conversion of testosterone (T) to dihydrotestosterone (DHT) in prostate and skin tissue, has been shown to reduce prostate cancer incidence and is used as a treatment for male pattern baldness. However, results from previous studies on the association between prostate cancer and male pattern baldness have been inconsistent, due partly to the retrospective nature of the study designs, small sample sizes, and differences in measuring patterns of hair loss. In this proposed study, we will test the hypothesis that men with male pattern baldness at age 45 have an increased risk for prostate cancer, using both questionnaire and genetic data from the prospective PLCO cohort, by: 1) determining the association between male pattern baldness at age 45 and prostate cancer in the PLCO (45,000 men, including 5,000 with prostate cancer); 2) determining the joint effects of male pattern baldness and genetic variants, in particular those involved in androgen metabolism, on prostate cancer risk in a case-control study nested within the PLCO (800 prostate cancer cases and 1,600 men without prostate cancer); 3) identifying genetic determinants of male pattern baldness, using a nested case-control study within the PLCO (1,700 men with male pattern baldness and 1,700 non-balding men); and 4) identifying non-genetic determinants of male pattern baldness, including serum androgen, diabetes, and body mass index. The PLCO is well suited to address our hypothesis and overcome several limitations in previous studies because it has a large number of cases (>5,000 cases), prospective data on prostate cancer incidence, nearly complete validation of outcome (prostate cancer), data on male pattern baldness (including severity), and existing data on a large number of genetic variants across the genome (over 1 million) and relevant biomarker data, including serum androgen levels. A better understanding of the link between male pattern baldness and prostate cancer may provide some insight into shared underlying etiologic factors. These findings can also help develop future strategies for preventing prostate cancer and male pattern baldness.