Mothers who did not breastfeed their children have significantly higher rates of type 2 diabetes later in life than moms who breastfed, report University of Pittsburgh researchers in a study published in the September issue of the American Journal of Medicine.

"We have seen dramatic increases in the prevalence of type 2 diabetes over the last century," said Eleanor Bimla Schwarz, M.D., M.S., assistant professor of medicine, epidemiology, and obstetrics, gynecology and reproductive sciences at the University of Pittsburgh. "Diet and exercise are widely known to impact the risk of type 2 diabetes, but few people realize that breastfeeding also reduces mothers' risk of developing the disease later in life by decreasing maternal belly fat."

The study included 2,233 women between the ages of 40 and 78. Overall, 56 percent of mothers reported they had breastfed an infant for at least one month. Twenty-seven percent of mothers who did not breastfeed developed type 2 diabetes and were almost twice as likely to develop the disease as women who had breastfed or never given birth. In contrast, mothers who breastfed all of their children were no more likely to develop diabetes than women who never gave birth. These long-term differences were notable even after considering age, race, physical activity and tobacco and alcohol use.

"Our study provides another good reason to encourage women to breastfeed their infants, at least for the infant's first month of life," said Dr. Schwarz. "Clinicians need to consider women's pregnancy and lactation history when advising women about their risk for developing type 2 diabetes."

Dr. Schwarz also is an assistant investigator at the Magee-Womens Research Institute. Co-authors of the study include Jeanette Brown, M.D., Jennifer M. Creasman, M.P.H., and David Thom, M.D., Ph.D., University of California, San Francisco; Alison Stuebe, M.D., M.Sc., University of North Carolina School of Medicine; Candace K. McClure, Ph.D., University of Pittsburgh; and Stephen K. Van Den Eeden, Ph.D., Kaiser Permanente, Calif.

The research was funded by grants from the National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Child Health and Development.