Male pattern baldness and prostate cancer risk in a population-based case-control study

Purpose: Male pattern baldness (MPB) and prostate cancer (PCa) share commonality as prevalent, heritable and androgen-related conditions. Studies exploring the relationship between the two conditions have been inconclusive. Using a population-based, case-control study of PCa, we explore the relationship between early-onset MPB and PCa risk. Methods: Cases were men aged 35-74 diagnosed with PCa between 2002 and 2005 in King County, Washington. Controls were frequency matched by age and identified by random digit dialing. Hair pattern at age 30 and at 1 year prior to diagnosis (cases) or reference date (controls) was determined using showcards. PCa risk associated with balding was assessed with logistic regression. Results: Data from 999 cases of PCa and 942 controls were analyzed. Hair loss at age 30 was more common in controls (25.2%) than cases (19.8%, p = 0.005), and those with hair loss at age 30 had a 29% relative risk reduction for PCa (OR 0.71, 95% CI 0.56-0.91). No risk reduction was seen for men only reporting hair loss at referent age (OR 0.90,95% CI 0.73-1.12). In men aged >60 at referent date, the risk reduction was greater for men with hair loss at age 30 from both the top of head and forehead (OR 0.55, 95% CI 0.33-0.93). Conclusion: Early-onset MPB was associated with a reduced relative risk of PCa in this population-based study. Further research into a possible mechanistic link between these prevalent and androgen-related conditions is warranted. (C) 2010 Elsevier Ltd. All rights reserved.