African-American women with low birth weights face heightened risk of developing type-2 diabetes, according to a study by the Boston University Medical Center.
The researchers said that low birth weight was defined as less than 2.5 kg and very low birth weight as less than 1.5 kg. The finding partially explains the higher incidence of type-2 diabetes in African-American populations that also experiences increased occurrence of low birth weight.
For the study, the researchers tracked over 21,000 women from the Black Women's Health Study during a period of 16 years. During the study period, they analysed characteristics like birth weight, current age, family history of diabetes, body mass index, physical activity and socioeconomic status.
The researchers found that women with low birth weight had a 13 percent high risk of developing type-2 diabetes than those with normal birth weight. And those with very low birth weight had a 40 percent high risk of developing the disease.
This is the first study to have studied the impact of birth weight on African-American populations.
"African American women are at increased risk of developing type 2 diabetes, and also have higher rates of low birth weight than white women," said Edward Ruiz-Narváez, ScD, assistant professor of epidemiology, in a press release. "Our study shows a clear relationship between birth weight and diabetes that highlights the importance of further research for this at-risk group."
The researchers said that there are likely two hypotheses for the phenomenon. The "thrifty phenotype hypothesis" states that once the newborn baby's body perceives a lack of nutrition, it readjusts itself to absorb more nutrition. As a result, it leads to an imbalance in metabolism that eventually causes type-2 diabetes.
The second, known as the "fetal insulin hypothesis", states that genes responsible for impaired insulin secretion also have a negative effect on birth weight. Some of the genes have been identified in recent studies, supporting the hypothesis.
The findings are published in the Journal Diabetes Care.
