Young women with larger than average breasts may have a higher risk of developing diabetes, a new study shows.

Researchers who studied over 90,000 women found those with above-average bra sizes at the age of 20 were up to 80 per cent more likely to get the disease than those with smaller breasts.

The scientists from the University of Toronto in Canada said the risks remained high, even when they allowed for whether the women were overweight, or had a family history of diabetes. This suggests breast size could be a new marker for who is most likely to develop the condition.

Around two million people in Britain are known to have diabetes but experts fear another one million are affected without realizing it.

Most suffer from type two diabetes, which is often linked with fatty diets and lack of exercise. The pancreas stops producing enough insulin to help muscles mop up glucose circulating in the blood.

Left untreated, the disease can cause irreversible damage to the kidneys, eyes, nerves, heart and major arteries.

Doctors fear an epidemic of type two diabetes in the UK because of unhealthy lifestyles and are already seeing the condition being diagnosed at much younger ages.

The latest study, published in the Canadian Medical Association Journal, suggests screening young women for breast size could help.

Researchers quizzed over 90,000 women in their late thirties on their bra sizes when they were aged 20. They then looked to see how many of the women had gone on to get diabetes.

The results showed women who wore 'B' cups at the age of 20 were 37 per cent more likely to have diabetes than those wearing 'A' cups.

For those in a 'C' cup at 20, the risks soared by 80 per cent, dropping to 64 per cent among those in a 'D' cup. It remains unclear why breast size might affect diabetes risks. But one theory is that fatty tissue in the breast, called adipose tissue, may be involved in making the body resistant to the effects of insulin.

Adipose tissue found around the stomach and on the back is already known to raise the risk of diabetes.

In a report on their findings, the researchers said: "We found a statistically significant link between bra cup size and the development of type two diabetes."

They said more research is needed but it may benefit doctors to include breast size measurements when assessing if a woman is at risk of diabetes.

(Agencies via China Daily February 4, 2008)