By Victoria Allen Science Correspondent For The Daily Mail
Published: 00:01 GMT, 1 November 2019 | Updated: 00:22 GMT, 1 November 2019
Men with high levels of testosterone may be almost a fifth more likely to develop prostate cancer.
A study of more than 200,000 British men suggests two hormones, picked up in a simple blood test, can predict their prostate cancer risk.
Men with the most testosterone in their blood, compared to those with the least, were 18 per cent more likely to be diagnosed with prostate cancer.
Those with the highest level of a second hormone, called IGF-I, saw their risk increase by 25 per cent compared to those with the lowest level.
Experts believe the hormones are a red flag for cancer because they fuel the growth of cells in the prostate, which keeps growing for a man's entire life.
When prostate cells grow and divide faster, there is more chance that errors will creep into their genetic code and mutated cells will be copied and cause cancer.
It is unlikely men will be given drugs to lower these hormones in the future, as that could have unintended side effects.
Men with high levels of testosterone may be almost a fifth more likely to develop prostate cancer. Those with the highest level of a second hormone, called IGF-I, saw their risk increase by 25 per cent. (Stock of prostate cancer cells)
But the findings, set to be presented at the National Cancer Research Institute conference in Glasgow, do suggest men could reduce their hormone levels naturally.
For example men on vegan diets have been found to have lower levels of IGF-I. That may be linked to evidence that men who eat less dairy have a lower risk of prostate cancer.
Dr Ruth Travis, who led the study from Nuffield Department of Population Health at the University of Oxford, said: 'We were interested in studying the levels of two hormones circulating in the blood because previous research suggests they could be linked with prostate cancer and because these are factors that could potentially be altered in an attempt to reduce prostate cancer risk.
'This research tells us that these two hormones could be a mechanism that links things like diet, lifestyle and body size with the risk of prostate cancer. This takes us a step closer to strategies for preventing the disease.'
More than 47,000 men a year are diagnosed with prostate cancer in the UK, and almost 12,000 die from it each year.
There is a blood test used to detect prostate cancer, which looks for a protein called PSA which leaks from the prostate, but it is often only