Men who are bald at age 45 are more likely to develop aggressive prostate cancer compared with those who keep their hair.
US researchers found those who lose hair at the front of their heads and have moderate hair-thinning on the crown were 40 per cent more likely to develop a fast-growing tumour in their prostate.
Prostate cancer is the most common cancer in men in the UK, with over 40,000 new cases diagnosed every year, according to NHS Choices.
Aggressive prostate cancer means the tumour is growing at a faster rate than slow growing, or non-aggressive tumours.
The researchers said both prostate cancer and male pattern baldness - hair loss in a distinct pattern - could both be caused by higher levels of male sex hormones - androgens - and androgen receptors.
A previous study by the Cancer Council of Victoria, Australia, said that higher levels of testosterone - the most common androgen - could trigger baldness.
This is because it has an adverse affect on hair follicles, acting on a hormone receptor to slow down hair production.
High levels of testosterone can also trigger the development of cancerous cells, the Australian researchers said.
The findings of the new study support earlier research suggesting that there might be a biological link between male pattern baldness and prostate cancer, the U.S. researchers said.
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If backed up by further studies, the findings could help identify men who may be at an increased risk of developing aggressive prostate cancer, they added.
Lead author Michael B. Cook,of the National Cancer Institute, in the US, said: "Our study found an increased risk for aggressive prostate cancer only in men with a very specific pattern of hair loss.
"This was baldness at the front and moderate hair-thinning on the crown of the head, at the age of 45.
"But we saw no increased risk for any form of prostate cancer in men with other hair-loss patterns."
He said: "While our data show a strong possibility for a link between the development of baldness and aggressive prostate cancer, it's too soon to apply these findings to patient care."
The study looked at 39, 070 men who were aged 55- 74 when they first enrolled on the US Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, a large trial looking into the effects of cancer screening.
The men were asked to recall what their hair-loss patterns looked like at age 45 using a picture tool.
During the follow up 1,138 prostate cancer cases were diagnosed, 51 per cent of which were aggressive.
The researchers defined an aggressive prostate cancer if it had a score of seven or more on the Gleason scale - a scale used to evaluate the prognosis of prostate cancer sufferers.
Aggressive prostate cancer also included men with stage three or four prostate cancer, or who had died with prostate cancer as the cause of death.
In the study, 72 was the average age a man was diagnosed with prostate cancer.
Dr Cook's team is currently conducting two additional studies exploring the relationship between male pattern baldness and risk of developing and dying from prostate cancer.
One of the studies includes a 'baseline dermatologic assessment' of male pattern baldness, which may be more reliable than the method used in the current study in which men recall the pattern of their hair loss at age 45.
The study was published in the Journal of Clinical Oncology.
