Diabetes significantly raises the risk of impotence, researchers have proven.

A major study by the universities of Exeter and Oxford has convincingly shown that type two diabetes is a cause of erectile dysfunction.

The researchers examined health data from more than 220,000 men - and showed that a genetic predisposition to type two diabetes is linked to erectile problems.

But they stressed that just because some people are genetically predisposed to get diabetes, it does not mean that this is their inevitable fate.

Evidence that type 2 diabetes is a cause of erectile dysfunction has been found in a largescale genomic analysis led by the University of Exeter and the University of Oxford

So if men improve their lifestyle - by exercising more and eating better - they can avoid diabetes and also have a functioning sex life.

And in time, the researchers believe common diabetes drugs could be 'repurposed' as treatments for impotence.

Researcher Dr Anna Murray, of the University of Exeter Medical School, said: 'Erectile dysfunction affects at least one in five men over 60, yet up until now little has been known about its cause.

'Our paper echoes recent findings that the cause can be genetic, and it goes further.

'We found that a genetic predisposition to type two diabetes is linked to erectile dysfunction.

'That may mean that if people can reduce their risk of diabetes through healthier lifestyles, they may also avoid developing erectile dysfunction.'

Diabetes is the one of the world's fastest growing health crisis, with the number of people suffering from the disease having doubled in just 20 years in the UK.

The problem is largely being driven by obesity, with 90 per cent of people with the condition suffering from the type 2 form, which is linked to lifestyle and diet.

WHAT IS IMPOTENCE? Erectile dysfunction, also known as impotence, is when a man is unable to get or maintain an erection. It is more common in the over-40s but affects men of all ages. Failure to stay erect is usually due to tiredness, stress, anxiety or alcohol, and is not a cause for concern. However, it can be a sign of an underlying medical condition such as high blood pressure or cholesterol, side effects of medication, or hormonal issues. Lifestyle factors than can affect the condition include obesity, smoking, cycling too much, drinking too much, and stress. Source: NHS Choices Advertisement

Diabetes is by itself already a huge health problem – putting the kidneys, heart, eyes and brain at risk.

But the new study, published in the American Journal of Human Genetics, proves the condition also has a major impact on men's sex life.

Medical firms have long vied to come up with different ways to treat erectile dysfunction, knowing there are fortunes to be made for those who can come up with an effective treatment.

When drugs giant Pfizer launched Viagra in 1998 its share price doubled within days. Since then, the pills have pulled in more than £1billion every year, even after its patent ended in 2013.

But not all men respond to the drug, and many others dislike having to take a pill during romantic moments.

Researcher Professor Michael Holmes, of the University of Oxford, said: 'Our finding is important as diabetes is preventable and indeed one can now achieve "remission" from diabetes with weight loss, as illustrated in recent clinical trials.

'This goes beyond finding a genetic link to erectile dysfunction to a message that is of widespread relevance to the general public, especially considering the burgeoning prevalence of diabetes.'

The researchers proved the link using a technique called 'Mendelian randomisation'.

For each man's DNA they looked for genes linked to type two diabetes - and then looked at which of these genes were also linked to erectile dysfunction.

If a gene is associated with both, it provides strong evidence this risk factor actually causes the disease, rather than just being linked to it.

They used this technique for 224,000 men, showing that the insulin resistance and high blood pressure that are a feature of diabetes also cause erectile dysfunction.

They wrote: 'Further research is needed to explore the extent to which drugs used in the treatment of type two diabetes might be repurposed for the treatment of erectile dysfunction.'