MEN with low testosterone levels are 20 per cent less likely to develop prostate cancer, a near-60-year Oxford University study has found.

Oxford scientists made the discovery after taking blood samples from around 19,000 men aged 34-76 - collected between 1959 and 2004.

The academics have presented their research at the National Cancer Research Institute in Liverpool.

Of the 19,000 men, 6,900 men went on to develop prostate cancer.

The extensive Cancer Research-funded study - carried out by several generations of scientists - revealed that men with unusually low amounts of testosterone in their blood were significantly less likely to develop the cancer.

The study's co-author, professor Tim Key from Oxford University, said: "This is an interesting biological finding that could help us understand how prostate cancer develops and progresses.

"Until now, we didn’t have a clear idea of the role testosterone played in prostate cancer risk.

"This is the first population study to support the theory that risk is lowered below a certain threshold of the hormone."

Professor Matt Seymour, NCRI clinical research director, said: “We know very little about the risk factors for prostate cancer, so this research raises some interesting questions for further research.

“In future, these results could be important in helping to devise an approach to reducing men’s risk of developing the disease.”