Hundreds of lives are being lost to prostate cancer each year because of high levels of obesity among men, a new UK study suggests.

Researchers claimed more than 1300 prostate cancer deaths could potentially be prevented every year in Britain if the average man was not overweight.

While obesity has been linked to 13 other cancers - including stomach, liver, pancreas and kidney cancers - the association between prostate cancer and weight has only just started to be unpicked by scientists.

The new study is being presented at the European Congress on Obesity in the Netherlands and published in the journal BMC Medicine.

In the study, researchers examined data on 218,237 men enrolled in the UK Biobank study whose body mass index score, waist circumference and waist-to-hip ratio were taken when they first enrolled in the study.

The participants were tracked for an average of 12 years, with 661 men dying from prostate cancer during the follow-up period.

After analysing the health data on the men who died from prostate cancer, and comparing it to those who did not, the researchers found that for every five additional points on a man's BMI score they were seven per cent more likely to die from prostate cancer.

And they had a six per cent higher risk of dying of prostate cancer for every additional 10cm on their waistline.

Researchers also performed an analysis of previous studies which examined information on almost 20,000 men who died from prostate cancer.

These studies suggested for every five additional points on a man's BMI score they were 10 per cent more likely to die from prostate cancer, with an additional 10cm waist size carrying a seven per cent higher risk.

While the mechanisms behind the findings are still unknown, researchers said the study still suggests men should try to maintain a healthy weight.

"Knowing more about factors that increase the risk of prostate cancer is key to preventing it," said Dr Aurora Perez-Cornago, from the University of Oxford, who led the research.

"Age, family history and black ethnicity are known risk factors but they are not modifiable, and so it is important to discover risk factors that it is possible to change."

Every year in the UK about 11,900 men die from prostate cancer.

And the researchers said men aged 55 to 64 have an average BMI score of 28.9 - which classes them as overweight.

Based on their findings, they calculated that if men were able to shave five points from their BMI score an estimated 1309 fewer prostate cancer deaths would happen every year in Britain.

And they pointed out that global health leaders recommend men should aim to have a waist circumference of 92cm.

Waist circumference is used as a measure of obesity as well as a BMI score because it indicates the amount of fat built up around a person's organs.

Dr Perez-Cornago added: "More research is needed to determine if the association is biologically driven or due to delays in detection (of prostate cancer) in men with higher adiposity (body fat).

"In either case, our latest results provide another reason for men to try to maintain a healthy weight."

Karis Betts, senior health information manager at Cancer Research UK, which funded the study, said while the relationship between prostate cancer and obesity needs further research, "It's still important to keep a healthy weight as obesity causes 13 other types of cancer".

Commenting on the study, Simon Grieveson, from Prostate Cancer UK, said: "Maintaining a healthy weight can protect against many cancers, but it is important to remember that prostate cancer can affect men of all shapes and sizes."