Birth Weight a Factor in Development of Type 2 Diabetes, Harvard Researchers Find

The saying “you are what you eat,” may be true, but it turns out what your mother ate may be more important in determining your future health.

Researchers from the Harvard School of Public Health report the first study that measures the relationships among birthweight, early development, and later behavior as an adult in development of type 2 diabetes mellitus (T2DM). It turns out that lower birthweight babies who go on to live unhealthy lifestyles as adults are 18% more likely to develop T2DM than those born at normal weight.

The results were published online in BMJ yesterday.

It’s another finding that supports efforts to improve nutrition for pregnant women to prevent diabetes and other poor health outcomes for their unborn children, according to the study’s lead author, Lu Qi, associate professor, Department of Nutrition, Harvard Chan School and Channing Division of Network Medicine, Brigham & Women’s Hospital.

Research presented last year at the 2014 Scientific Sessions of the American Diabetes Association examined the relationship between women who exercised during their final trimester of pregnancy and neonatal adiposity; the study suggested that women at risk of having overweight children should exercise more during pregnancy.

Qi and colleagues examined data from 149,794 healthy men and women involved in 3 trials—the Health Professionals Follow-up Study, the Nurses’ Health Study, and the Nurses’ Health Study II—for 20 to 30 years. Study participants were scored on 5 lifestyle factors: diet, smoking, alcohol use, body mass index (BMI) and physical activity levels. Those who did not provide birth weight were excluded.

Among the eligibile participants, 11,709 new cases of T2DM were diagnosed during the study period. Of these, 22% were attributed to lower birth weight alone, 59% were attributed to unhealthy lifestyle alone, and 18% were attributed to a combination of the 2 factors.

How does low birthweight cause future T2DM? A pregnant woman with poor nutrition may cause her fetus to prepare for survival in an environment with little food; later on, a child who developed to adapt to a world without resources now lives with abundance, and this can result in T2DM.

The result of this phenomenon is seen in developing countries, where rapid transitions to Western lifestyles have led to soaring rates of T2DM, alongside rising obesity and cigarette smoking. “Our findings suggest that the public health consequences of unhealthy lifestyles would be larger in low birth weight populations,” Yangping Li, lead author and research scientist, Department of Nutrition, said.