New research from the University of Iowa shows that lower birth weight is associated with an increased risk for type 2 diabetes in white and black postmenopausal women in the U.S.

Type 2 diabetes is the most common form of diabetes. The Centers for Disease Control and Prevention estimates more than eight percent of the U.S. population has the chronic disease, and if current trends continue, one in three U.S. adults will have diabetes by 2050.

To date, the UI study is the largest to examine the association of birth weight with type 2 diabetes in a multi-ethnic group of postmenopausal women.

“Our findings confirm what we’ve seen with other studies in that low birth weight is a risk factor for later life type 2 diabetes,” says Kelli Ryckman, UI assistant professor of epidemiology in the College of Public Health and lead author of the study.

“What was unique about our study is that it was a large cohort of postmenopausal women who were very diverse in ethnicity and race.” Similar studies have looked at younger and less diverse populations, Ryckman says. The study appears in the journal Diabetes & Metabolism.

The researchers performed a cross-sectional analysis of data from the Women’s Health Initiative Observational Study. Of the 75,993 women in the analysis, just over five percent (4,002) reported having diabetes. The women were categorized by self-reported birth weight, and models were adjusted for age, ethnicity, body mass index (BMI), and other pertinent risk factors such as family history of diabetes and physical activity.

The researchers found that low birth weight (less than six pounds) in white and black women was significantly associated with an increased risk for type 2 diabetes compared to women in the referent six to 7.9 pound birth weight category. The study lacked sufficient numbers of Hispanic and Asian women to detect associations in those groups.

The disease is complex and has multiple influences, including lifestyle, genetics, and early development, Ryckman says.

“Early life development factors really do matter,” says Ryckman. “Healthy behaviors before and during pregnancy are important because we are passing on to our children, even at that stage, what their risk will be for later life chronic disease.”

The investigators note that additional studies are needed to evaluate the association between birth weight and type 2 diabetes in minority groups and to better understand the underlying reasons for the observed differences among different ethnicities.

“It is particularly important to understand the later life risks of low birth weight in black populations as the prevalence of delivering a low birth weight infant, in the United States, is much higher among black women with a prevalence of about 12 percent compared to white (seven percent), Hispanic (six percent), and Asian (eight percent) women,” the authors state.

In addition to Ryckman, the UI researchers included Cassandra Spracklen, a graduate student in epidemiology; Robert Wallace and Jennifer Robinson, professors of epidemiology and internal medicine; along with colleagues from the Fred Hutchinson Cancer Research Center, University of California at Davis, University of Tennessee Health Science Center, Medstar Health Research Institute and Georgetown/Howard Universities Center for Clinical and Translational Research, University of California at Los Angeles, The Commonwealth Medical College, and University of Hawaii.

The Women’s Health Initiative program was funded by the National Heart, Lung, and Blood Institute, National Institutes of Health.