Higher maternal sugar levels increases risk of childhood obesity

Aug 28 2007

Treating diabetes during pregnancy can break the link between gestational diabetes and childhood obesity, according to a Kaiser Permanente study featured in the September issue of Diabetes Care.

The largest study of its kind, this research shows that the risk of childhood obesity rises in tandem with a pregnant woman's blood sugar level and that untreated gestational diabetes nearly doubles a child's risk of becoming obese by age 5 to 7. The study also shows for the first time that by treating women with gestational diabetes, the child's risk of becoming obese is significantly reduced. In fact, children whose moms were treated for gestational diabetes had the same risk for becoming obese as children whose mothers had normal blood sugar levels.

Researchers at Kaiser Permanente's Center for Health Research (CHR) in Portland and Hawaii used the organization's integrated databases to analyze medical records of 9,439 mother-child pairs. The subjects were members of the health plan in Oregon, Washington and Hawaii and gave birth between 1995 and 2000. The authors found that treating gestational diabetes lowers the child's risk of becoming obese during childhood to the same levels of those pregnant mothers with normal blood sugar levels.

Gestational diabetes, the condition in which pregnancy triggers insulin resistance and raises the woman's blood glucose level (hyperglycemia), affects up to 8 percent of pregnant women each year in the United States. The rate of childhood obesity in this country more than doubled in the last two decades, so much so that it is now one the nation's fastest growing health conditions. Nearly 7 million overweight and obese children in the United States today will grow up to become overweight or obese adults.

"Hyperglycemia during pregnancy is clearly playing a role in America's epidemic of childhood obesity," said Teresa Hillier, MD, MS, an endocrinologist and senior investigator at CHR Northwest and Hawaii, and the lead author of the study. "The key finding here is that the risk of overweight and obese children rises in step with higher levels of blood sugar during pregnancy. The good news for pregnant women is that by treating gestational diabetes, your children's risk of becoming overweight or obese drops considerably."

"My advice to pregnant women is three-fold: Discuss gestational diabetes screening with your doctor, usually between weeks 24 and 28 of pregnancy; if you have gestational diabetes, work with your physician to treat it, and stick with the treatment during your pregnancy. It's the best thing you can do to reduce your child's risk of obesity," said Dr. Hillier.

Funded by a grant from the American Diabetes Association, the study was made possible by Kaiser Permanente's interlinked, computerized databases. As the nation's largest and oldest integrated care delivery system, Kaiser Permanente researchers can anonymously review patient records dating back many years and look for connections with the patient's family members and other aspects of the members' health.

The women in the study were screened during pregnancy for blood sugar level and gestational diabetes. The women's children were measured for weight between the ages of 5 and 7 – the so-called "adiposity rebound" period, a strong predictor of adult obesity. The relationship between maternal blood sugar and childhood obesity was then analyzed.

Children of mothers with high levels of blood sugar who were untreated were 89 percent more likely to be overweight and 82 percent more likely to be obese by the time they were 5 to 7 years of age, compared to children whose mothers had normal blood sugar levels during pregnancy.

"The obesity risk of children whose mothers had the highest blood sugar levels—and were treated for gestational diabetes—was not statistically different than children of mothers with normal blood sugar levels. This suggests that the 'metabolic imprinting' for childhood obesity that results from gestational diabetes in pregnant women may be reversible," Hillier said.