Bald men are more likely to get prostate cancer.

A new study from the University of Toronto confirmed that baldness in men has a strong correlation with the risk of developing prostate cancer.

The most common cancer for men in Canada, studies have already determined a few known risk factors for prostate cancer including advancing age, family history and certain genetic markers. But the connection between male pattern baldness and prostate cancer is a more recent finding, with researchers attributing the link to high testosterone levels.

The new study involved 394 men with no past history of prostate cancer who underwent a biopsy screening at the Princess Margaret hospital in Toronto, with the men being scored on a modified version of the Norwood scale for baldness – a well-used ranking of baldness that runs from one to seven (researchers scored the men’s hair loss on a scale from one to five). The researchers found that male pattern baldness represents a “strong and independent risk factor” for prostate cancer and that the higher the grade of baldness, the higher the risk of developing prostate cancer.

“We were trying to be a bit provocative (about the genetic tests), but it’s true,” said Dr. Neil Fleshner, head of urology at Toronto’s Princess Margaret Cancer Centre and co-author of the study published in the Canadian Urological Association Journal. “If you get it (baldness) early and you get a lot of it, those people are particularly at risk.”

Prostate cancer represents 21 per cent of all new cancers in men and is the third leading cause of death from cancer in men, according to the Canadian Cancer Society. Prostate cancer involves the abnormal growth of cells of the prostate and manifests through symptoms such as difficulty or pain when urinating or ejaculating, frequent need to urinate and blood in the urine or semen.

The researchers plan on following up with another study involving an additional 175 patients to look into the biological factors behind the connection. In the meantime, Fleshner says, doctors may well be best served by viewing male pattern baldness as a potential risk factor in their screening decision-making. “If they’re on the borderline of whether to do a biopsy … you may want to take into account the added risk factor of the men’s head of hair,” says Fleshner.

A similar study was conducted last year by the National Cancer Institute in Maryland, U.S., which found that men with moderate balding had an 83 per cent chance of developing prostate cancer and that any degree of baldness in men entailed a 56 per cent higher risk of developing fatal prostate cancer.

Epidemiologist at the National Cancer Institute and study co-author Dr. Michael Cook said that the overlap between prostate cancer and baldness is attributable to higher male hormone levels. “Male sex hormones called androgens, such as testosterone, are thought to underlie both male baldness and prostate cancer progression,” says Cook. “And our study, combined with others, provides an evidence base that supports the ideas of shared risk factors for these two conditions.”