Common pattern baldness (androgenetic alopecia, AGA) is the most common form of hair loss in humans. In Caucasians, normal male hair loss, commonly known as “male pattern baldness” (MPB), is noticeable in about 20 % of men aged 20, and increases steadily with age, so that a male in his 90s has a 90 % chance of having some degree of MPB. In addition to being among the most common natural conditions that make men self-conscious, recent studies indicate associations of MPB with benign prostatic hyperplasia, and with risk factors for clinical prostate cancer. Our results indicate that 81% of the total variance could be attributed to additive genetic effects (95 % CI:77-85 %). By studying families, we hope to understand more about how genes and environment influence natural hair loss (that is, not due to illness or medication) as well as other associated aspects of health.
(D.R. Nyholt, N.G. Martin)