June 25, 2010

BIRMINGHAM, Ala. - Research from the University of Alabama at Birmingham (UAB) provides the first evidence that Type 2 diabetes in children may be linked to their mothers' blood sugar during pregnancy.

Pre-pubertal children of women with high blood sugar during pregnancy have alterations in the way their bodies process carbohydrates - alterations that may lead to Type 2 diabetes. The findings were presented this week at ENDO 2010, the annual meeting of the Endocrine Society, in San Diego.

Children who were prenatally exposed to relatively high maternal blood glucose, or sugar levels, had lower insulin sensitivity and greater post-meal insulin secretion - independent of body composition and other confounding factors; the authors say that suggests that the prenatal environment may program fetal carbohydrate metabolism.

"These findings support the concept that maternal blood glucose plays a role in how the developing fetus manages insulin secretion from the pancreas and also of insulin sensitivity at target tissues such as the skeletal muscle and liver," said Paula Chandler-Laney, Ph.D., a post-doctoral fellow in the UAB Department of Nutrition Sciences and study co-author.

Reduced insulin sensitivity impairs the body's ability to clear glucose from the blood stream, driving up insulin secretion from the pancreas; eventually this may exhaust the pancreas so that it can no longer produce insulin. This is known as Type 2 diabetes -when the body no longer can produce enough insulin to manage blood sugar. 

"Many other studies have shown that children from mothers with high blood sugar during pregnancy are at greater risk for Type 2 diabetes," said Chandler-Laney. "Now, this study is the first to show that even for children who have not yet become diabetic, there are changes in the way the body secretes and responds to insulin following prenatal exposure to high maternal blood sugar." 

In conjunction with the UAB Center for Women's Reproductive Health, the team studied 21 mother-child pairs of African and European descent. Maternal blood glucose concentration during the standard gestational diabetes-screening test was retrieved from medical records. Children's body composition was measured by dual-energy X-ray absorptiometry (DXA), and insulin sensitivity and secretion were assessed by mathematical modeling of insulin, glucose, and C-peptide concentrations following a liquid test meal. 

"This was a small study, but the results certainly indicate that a woman's blood glucose during pregnancy is involved in the processes that determine insulin sensitivity and secretion in her children," said Barbara Gower, Ph.D., professor of Nutrition Sciences and a study co-author.

"Women, particularly women in high-risk groups, should be especially sensitive to their blood sugar levels during pregnancy," Gower said. "It would perhaps be beneficial to find better ways to help high-risk women control their blood sugar during pregnancy. A prenatal intervention might help to defend their children against obesity and Type 2 diabetes."

The authors suggest that further studies, starting during pregnancy and following children through early childhood, will be necessary to determine whether changes in insulin sensitivity and secretion are present at birth and track through childhood into adulthood among children exposed to high maternal glucose. 

Nearly 8 percent of the United States population, 23.6 million children and adults, have diabetes. Type 2 is the most common form. It is more common in African-Americans, Latinos, Native Americans, Asian Americans, Native Hawaiians and other Pacific Islanders.

This research was funded by the Thrasher Research Fund and the National Institutes of Health (NIH).

About the UAB Department of Nutrition Sciences

The UAB Department of Nutrition Sciences is a leader in nutritional research, patient care and education and consistently ranks among the top programs of its kind in the country. Progressive clinics supported by the department average 2,500 patients a year in programs for nutrition, weight management, osteoporosis prevention and cancer support.