Impotence may be a sign of heart disease and diabetes, doctors have revealed.

A study has found the condition is an early warning of underlying medical problems - even in men of healthy weight not usually considered to be at risk.

Diabetes can go unrecognised for four to seven years, doctors believe.

Meanwhile, half of those who die from coronary disease have never been diagnosed with heart problems.

The research found impotent men of normal weight were twice as likely to develop risk factors for heart disease and diabetes.

Impotence can occur for psychological reasons and because clogged-up arteries affect the blood supply to the penis.

In the study, which is published in the Journal of Urology, a team from the New England Research Institutes in Massachusetts, charted the health of 928 men aged 40 to 70 over 15 years.

The U.S. team looked at markers for metabolic syndrome, a sign of heart disease and diabetes.
These markers include raised cholesterol, high blood sugar, blood pressure and obesity.

They found a two-fold increase in risk for metabolic syndrome among men of a healthy body weight with erectile dysfunction.

Dr Graham Jackson, chairman of the Sexual Dysfunction Association, said the findings were a wake-up call for doctors to investigate impotence in men who were not overweight.

'In this instance, erectile dysfunction can be a better warning signal (of heart disease) than a large beer belly,' he said.