Young women with large breasts have a significantly higher chance of developing Type 2 diabetes later in life than those who
are less buxom, a Canadian-led study suggests.

Women who wear a D-cup bra at age 20 are almost 60 per cent more likely to develop the ailment than those who wear a smaller A cup at 20 – independent of other body weight factors, the study indicates.

"It isn't just about abdominal obesity, but also the contribution of fat tissue in another place," says Dr. Joel Ray, a St. Michael's Hospital scientist and the lead study author.

Type 2 diabetes most often occurs when the body becomes resistant to the sugar-metabolizing insulin produced in the pancreas.

And obesity, especially fat storage in the abdominal area, has long been pegged as a key contributor to the ailment.

But the study, which appears today in the Canadian Medical Association Journal, suggests that fat storage in women's breasts may pose additional and independent diabetes risks. And those risks appear to increase progressively with cup size, Ray says.
 

"I think there is good background rationale as to why there might be a relationship (between diabetes and breast size)," Diane Finegood, head of diabetes and nutrition at the Canadian Institutes of Health Research, said of the study.

Ray says the study is just a preliminary look at the role breast size may play as a diabetes predictor and that further research is needed.

He stresses general obesity, especially abdominal fat, remains by far the major risk factor for Type 2, or adult-onset, diabetes.

Women who reported high body mass indexes plus large breast sizes at age 20 were about 4 times more likely to develop diabetes than those with small breasts and low obesity levels.

Ray says obesity in adolescence often increases breast size and that most of the diabetes risk seen in the study is almost certainly due more to overall weight than cup size.

And obese girls tend to enter puberty earlier, meaning breasts develop at a younger age and often at a more accelerated and pronounced pace. Still, he says, the study of 92,000 women showed those with large breasts and were otherwise thin did exhibit a statistically significant propensity to develop diabetes. The study used data from an ongoing U.S. Nurse's Health Study II, which was begun in 1989.