Measures of abdominal obesity in early pregnancy may inform early screening and prevention strategies for gestational diabetes, according to Kaiser Permanente study.
By Brett Israel, Senior Communications Consultant
Heading into Thanksgiving, when food is the focus of family gatherings, new research provides another reason for women who are thinking of becoming pregnant to be mindful of their diet and physical activity. The study found that pregnant women with abdominal obesity in early pregnancy, even without other risk factors, were at an elevated risk of gestational diabetes.
The study, “Central Obesity Increases the Risk of Gestational Diabetes Partially Through Increasing Insulin Resistance,” was published today in the journal Obesity.
The study of 1,750 pregnant women found that abdominal obesity, as measured by waist-to-hip ratio or waist circumference in early pregnancy, was a predictor of gestational diabetes even when controlling for other conventional risk factors including overweight or obesity, as measured by body mass index before pregnancy.
“Our findings may have significant clinical implications, particularly considering that women with abdominal obesity, but the absence of other risk factors including overall obesity, are not considered a target population for early risk assessment or preventive management of gestational diabetes,” said lead author Yeyi Zhu, PhD, a research scientist with Kaiser Permanente Northern California’s Division of Research.
Measuring a person’s hips and waist is an established method to measure abdominal obesity. Previous research has shown that people with apple-shaped bodies (with more weight around the waist) are at a higher risk of health problems than people with pear-shaped bodies (with more weight around the hips). The study used the World Health Organization’s cut-off for central or abdominal obesity as a waist-to-hip ratio of 0.85 or higher or a waist circumference of 88 centimeters or higher among women, which tend to be the inflection points between apple- and pear-shaped bodies.
The study found that women above the cut-off, or those with apple-shaped bodies, had more than 2.5 times the risk of gestational diabetes compared to women below the cut-off, or those with pear-shaped bodies. Women with both central obesity and other risk factors had more than 6 times the risk of gestational diabetes.
Established risk factors for gestational diabetes include age greater than or equal to 35 years, minority race/ethnicity other than white, overweight or obese before pregnancy, family history of diabetes, previous history of gestational diabetes, and pre-existing hypertension.
The association between abdominal obesity in early pregnancy and gestational diabetes risk was partially mediated through increased insulin resistance in mid-pregnancy, suggesting that strategies targeting abdominal obesity and/or insulin resistance may help mitigate a woman’s risk of gestational diabetes, according to Zhu.
The study analyzed data from the prospective Pregnancy Environment and Lifestyle Study cohort of multi-racial/ethnic women led by senior author Assiamira Ferrara, MD, PhD, associate director of Women’s and Children’s Health at the Division of Research. Waist circumference and hip circumference were measured early in pregnancy at gestational weeks 10 to 13.
“This suggests that women who intend to become pregnant should plan better eating and more exercise, which in turn reduces central obesity and high level of insulin, to reduce their risk of gestational diabetes,” Dr. Ferrara said.
Additional co-authors of the study, all from the Division of Research, include research scientist Monique M. Hedderson, PhD, biostatistician Charles P. Quesenberry, PhD, and data analyst Juanran Feng.
This work was supported by the National Institute of Environmental Health Sciences (grant R01ES019196) and National Institutes of Health Building Interdisciplinary Research Careers in Women’s Health Program (grant 3K12HD05216).