Obese Teens Whose Moms Had GDM at Greater Risk for Diabetes

Marlene Busko

August 27, 2014

Being exposed to gestational diabetes mellitus (GDM) in the uterus appears to greatly up the odds of developing early diabetes in adolescence, a new study suggests. More specifically, among obese children around age 12 who had normal initial glucose tolerance, those whose mothers had GDM were close to 6 times more likely to develop impaired glucose tolerance or type 2 diabetes by around age 15.

The youth with mothers who had GDM also had a low disposition index, which is an indication of the ability of the pancreas to compensate for insulin resistance. "In other words, these children have reduced ability to overcome their insulin resistance by enhancing insulin secretion from beta cells," senior author Ram Weiss MD, PhD, associate professor in the department of human metabolism and nutrition, Hebrew University, Jerusalem, explained to Medscape Medical News.

Thus, "the ever-growing number of women with gestational diabetes (18%) suggests that the future will be filled with children with early diabetes at a rate that far exceeds the current prevalence," the authors warn.

Although this study was not designed to develop screening guidelines, the authors suggest that obese children and adolescents who were exposed to GDM should been screened with oral glucose testing, particularly if other risk factors are present.

The study was published online August 25 in Diabetologia.

High Glucose in Utero, Diabetes Risk in Offspring?

The prevalence of GDM and of type 2 diabetes in 10- to 19-year-old children has increased over the past 2 decades, the authors note. However, the risk of developing impaired glucose tolerance in children exposed to diabetes in utero is unclear.

To investigate this, they examined data from obese adolescents with diverse ethnicities who participated in the Yale Pathophysiology of Type 2 Diabetes in Youth Study .

The cohort consisted of 210 participants (82.3%) who were not exposed to GDM and 45 participants (17.7%) who were exposed to GDM. All participants had a normal oral glucose tolerance test at baseline and repeated the test after about 2.8 years.

"Alarmingly, 31.1% of obese children with normal glucose tolerance who were exposed to GDM in utero developed impaired glucose tolerance/diabetes over a relatively short follow-up period of less than 3 years on average," the researchers write. Only 8.6% of the children who were not exposed to GDM developed these outcomes in this timeframe (P < .001).

Thus, "exposure to high glucose levels in utero [may cause] permanent changes in the developing pancreas that may affect beta-cell number/function in the future," Dr. Weiss suggested.

"Accumulating Snowball of Risk of Type 2 Diabetes"

Asked to comment, Louise Kelstrup, MD, PhD student, from the Center for Pregnant Women with Diabetes, department of obstetrics, Rigshospitalet, Copenhagen University Hospital, Denmark, said that the findings are important for obstetricians and endocrinologists treating pregnant women with diabetes and for pediatricians, as they provide insight into the impact of the intrauterine environment on the growing fetus and the metabolic consequences later in life.

"This could lead to more profound questions when obtaining a medical history, including not only familial predisposition to type 2 diabetes but also questions about maternal health during pregnancy," she said.

The prevalence of GDM is especially increasing in countries such as India, China, and Brazil with fast-growing economies, where individuals now have access to more high-calorie foods and are also becoming more sedentary, Ms. Kelstrup noted.

Moreover, "because of this nongenetic transmission of diabetes disposition from mother to child, I agree that we can expect high rates worldwide of individuals with high risk of type 2 diabetes already from time of birth, which can be additive to a high-risk lifestyle later in life," she added. "In other [words], an accumulating snowball of risk of type 2 diabetes has started to roll."

Pregnant women should be carefully screened and receive intensive treatment to minimize negative metabolic consequences for their offspring, and high-risk children who were exposed to GDM in utero should be screened regularly — although more research is needed to help clarify the effect of screening, she said, echoing the study authors.

The authors have reported no relevant financial relationships.

Diabetologia. Published online August 25, 2014. Abstract

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