Losing your hair is annoying for sure, but baldness in men has also been linked to health conditions like aggressive prostate cancer and heart disease. Researchers have been trying to figure out what causes male-pattern baldness for both health and aesthetic reasons—aesthetic concerns can become psychological ones, after all—and now a UK group has identified more than 200 genes linked to going bald.
For a new study in PLOS Genetics, researchers from the University of Edinburgh looked at genetic data and health questionnaires from more than 52,000 men ages 40 to 69 in enrolled the UK Biobank study; their average age was 57. They divided the men into four groups based on self-reported hair loss: none (about 32 percent), slight (23 percent), moderate (27 percent), and severe (about 19 percent).
They identified 287 genetic regions linked to baldness, many of them related to hair structure and development including growth, thickness, and texture. The bulk of the genetic variants were on the autosomes, or chromosomes which don't determine sex characteristics, but 40 were on the X chromosomes which men get from their mothers. (Men are XY, women are XX.) One of the X chromosome hits was the androgen receptor; androgens are male sex hormones including testosterone that also exist in women, albeit in lower amounts. The authors wrote: "It is possible that the hair structure proteins interact biologically with sex hormones, leading to a higher prevalence of baldness."
It's the largest-ever genetic analysis of male-pattern baldness; before this study, the largest published work had identified just eight genetic regions linked to the condition. The researchers also developed a formula intended to predict the chances that a person will go bald based on the presence or absence of genetic variants but accurate predictions are still "crude." They said the formula could be used in the future to identify which groups of men are more susceptible to hair loss than others. But, in general, knowing which genes are linked to male-pattern baldness could also help scientists develop drugs to treat hair loss.
The study's co-author noted in a release that they didn't look at age of onset, but if they had, they might have been able to find even stronger genetic signals for men with early-onset hair loss.