Women who develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health (NIH) and other institutions. The findings provide insight into the genetic factors underlying the risk of type 2 diabetes and may inform strategies for reducing this risk among women who had gestational diabetes.
The study was conducted by Mengying Li, Ph.D., of the Division of Intramural Population Health Research at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and colleagues. It appears in BMJ Open Diabetes Research & Care.
“Our study suggests that a healthful diet may reduce risk among women who have had gestational diabetes and are genetically susceptible to type 2 diabetes,” said the study’s senior author Cuilin Zhang, M.D., Ph.D., of NICHD’s Division of Intramural Population Health Research. “However, larger studies are needed to validate these findings.”
Gestational diabetes (high blood sugar that first occurs during pregnancy) increases the risk of complications for mothers and their infants. In most cases, the condition resolves soon after the baby is born, but nearly half of women with gestational diabetes develop type 2 diabetes later in life. Type 2 diabetes increases the risk of heart disease, kidney disease and other health problems. However, little research has been done on the genetic factors influencing a woman’s risk for progressing to type 2 diabetes after gestational diabetes.
In the study, researchers analyzed data from 2,434 women with gestational diabetes who participated. The study followed women before, during and after pregnancy and captured data on their health later in life. Of the original group, 601 women with gestational diabetes developed type 2 diabetes.
Previous research has linked variations in certain genes (called single nucleotide polymorphisms) to a higher risk of type 2 diabetes. In the current study, researchers checked genetic scans of the 2,434 women for the presence of 59 gene variants thought to be more common in people who have type 2 diabetes. The researchers found that women who had the largest proportion of these gene variants were 19 percent more likely to develop type 2 diabetes, compared to those who had the lowest proportion of these variants.
The researchers also ranked the women’s diets according to the proportion of healthy foods. Among women who adhered to a healthier diet, the risk associated with the gene variants was lower than that of the other women, but the differences between the two groups were not statistically significant.
The authors believe their study is among the largest to date that looks at genetic factors underlying development of type 2 diabetes among women with prior gestational diabetes. However, the number of women participating in the study may not be large enough to find a significant interaction between healthy diet and genetic susceptibility in relation to this risk.