The ancient Egyptians thought baldness was caused by a curse from the gods, which meant the Rogaine of the day was swallowing a mixture of onions, honey, iron, lead and alabaster, and reciting a prayer to the sun god Ra.
These days, the causes are understood to be mostly hereditary, and a new study published in Nature Communications demonstrates just how many genetic underpinnings might lead to male-pattern baldness. Researchers at the Institute of Human Genetics at the University of Bonn in Germany used data from more than 22,000 people, 17,000 of them customers of the California DNA testing and mapping company 23andMe. Customers can, and often do, sign off to participate in research collaborations, says David Hinds, the company's principal scientist for statistical genetics. About half of those whose data was studied showed male pattern baldness and the other half were a control group.
The German researchers found 63 genetic markers (23 of them not previously reported) associated with men losing hair as they age. Many of these genes were related to ones involved in hormonal signaling. The markers coincide with ones connected to prostate cancer, sudden cardiac arrest, neurodegenerative disorders, and other health ailments. Understanding why men suddenly go Jean-Luc Picard may help scientists better understand those serious medical concerns, too.
Genetic researchers have long understood that genetic components cause male pattern baldness, says Stefanie Heilmann-Heimbach, co-author of the study. Other often-inherited traits, like short stature, are correlated with it. Men of European descent also go bald 80 percent of the time, while hair loss is less common and occurs later in life for men of African and Asian ancestry.
"Basically, some disorders have been associated with baldness on an epidemiological level, including cardiovascular disease and cancer," Heilmann-Heimbach says. "The genetic basis for baldness could be a sign of a disease."
She says the study shouldn't be "distressing" to balding men, but that placing a medical context around male pattern baldness will help researchers understand a variety of genetic markers and how they play out in the body as it ages.
Hinds says male pattern baldness is a particularly rich subject for researchers trying to decode genes, because it is known as an expression of genes; 80 percent of the factors that cause it are inherited.
"We know that male-pattern baldness has to do with the biology in androgen hormone response," he says. "The hair follicle is responding to male hormones. We know that other diseases—like prostate cancer—are affected by male hormone levels, so there's reason to think it's helpful in understanding that."