A larger hip circumference is associated with a reduced risk of diabetes and heart disease, hints new research published this month.

Among 10,767 people who were followed from 1987 to 1998, hip circumference was directly related to the occurrence of diabetes, Dr. Emily D. Parker, from HealthPartners Research Foundation, Minneapolis, and colleagues report in the American Journal of Epidemiology for April.

When waist circumference, overall weight, and other possible “confounding” factors were included in the analysis, an inverse link between hip circumference and diabetes was noted - that is, the larger the hips, the lower the risk.

The investigators also observed that an increase in hip circumference correlated with a decrease in risk of heart disease, after adjusting for waist circumference, body weight, and other confounding factors.

The mechanisms underlying these apparent protective associations are unclear, the investigators note. They speculate that larger hips may indicate a proportionally greater lean body mass, which in turn has been shown to decrease the risk of diabetes. Regarding heart disease, the association may relate to an increase in subcutaneous fat, or fat that collects just under the skin, which may reduce free fatty acid circulation.

Clearly, further studies are needed to figure out why having larger hips may protect against diabetes and heart disease, the researchers conclude.

SOURCE: American Journal of Epidemiology, April 2009.