The risk of developing type 2 diabetes following gestational diabetes mellitus (GDM) is markedly increased among women who have a high body mass index (BMI) and who gain weight following pregnancy, warn researchers from the US National Institutes of Health (NIH).
And while the risk is increased with baseline BMI and postpartum weight gain separately, those who have a high BMI and gain more than 5 kg following their pregnancy are more than 43 times more likely to develop type 2 diabetes than women with a baseline BMI of less than 25 kg/m2 who gain less than 5 kg, they calculate.
The research, examining data from the Nurses' Health Study II, is published in Diabetologia by Wei Bao, MD, PhD, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Maryland, and colleagues.
Senior author Cuilin Zhang, MD, MPH, PhD, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, said this study is the one of the first to comprehensively examine the associations of BMI and weight change with risk of type 2 diabetes in women with a history of gestational diabetes.
She told Medscape Medical News that high baseline BMI and postpartum weight gain are both strong risk factors for type 2 diabetes. "Together they may have interaction or stimulogenic effect, which is why [women with both]…have exceptionally high risk.
"Because these are high-risk women to begin with, they probably have some underlying problem with insulin sensitivity or beta-cell function, and maybe all these risk factors together [result in] a really high risk of type 2 diabetes," she suggests.
Dr Zhang said that the message from the findings to these high-risk women is clear. "I think they really need to pay good attention to their weight [and] maintain their weight, minimize weight gain, and, if possible, try to lose weight."
Commenting on the results, Rudy Bilous, MD, from Newcastle University, Newcastle upon Tyne, United Kingdom, described the findings as "very important."
Speaking to Medscape Medical News, he said: "Because a lot of the previous studies in the US have been primarily in Hispanic women who have a high background rate of type 2 diabetes anyway, the fact that most of these women are white [European] in origin…[adds] important new data to what we already understand about the risk of type 2 diabetes and gestational diabetes mellitus."
Dr Bilous said that the findings reinforce the recommendations of the recently published UK National Institute for Health and Care Excellence diabetes in pregnancy guidelines.
These recommend that women who have gestational diabetes should be under active surveillance for type 2 diabetes. This includes a postpartum test, either as a fasting blood glucose at 6 to 8 weeks or an HbA1c measurement beyond 13 weeks, and then, if that is normal, annual testing thereafter to pick up the development of diabetes.
Study Results
As part of the ongoing Diabetes & Women's Health Study, the NIH team examined data on 1695 women from the Nurses' Health Study II who developed incident gestational diabetes between 1991 and 2001.
The women completed biennial questionnaires to provide information on health-related behaviors and disease outcomes, and they were followed up until they returned the 2009 questionnaire. They were classified as underweight, normal weight, overweight, or class I, II, or III obese using NIH guidelines for BMI.
During 18 years of follow-up, consisting of 18,596 person-years, there were 259 documented incident cases of type 2 diabetes among the women. The mean follow-up period was 13.1 years. The average weight gain during follow-up was 0.47 kg per year after the index GDM pregnancy.
Following adjustment for age, parity, and other major diabetic risk factors, the researchers found that each 1-kg/m2 increase in BMI was associated with a hazard ratio (HR) for type 2 diabetes of 1.16 for baseline BMI and 1.16 for most recent BMI.
Furthermore, each 5-kg increment in weight gain following the development of GDM was associated with an increased risk of type 2 diabetes, at an adjusted HR of 1.27.
The highest risk of type 2 diabetes was seen in women with a baseline BMI of ≥30 kg/m2 and who gained 5 kg or more in weight after GDM, at an adjusted HR of 43.19 compared with women with a baseline BMI of <25.0 kg/m2 and who gained less than 5 kg following GDM.
The team found that the positive associations between BMI and weight gain and the risk of type 2 diabetes held across different categories of age, family history of diabetes, quality of diet, physical-activity level, duration of breastfeeding, and time since GDM pregnancy.
Dr Zhang said it's important to follow these women up.
"Usually when type 2 diabetes is diagnosed, it's quite late," she explained. "The majority have already developed comorbidities. But when we follow up these high-risk women, we have the opportunity" to look for early biomarkers for type 2 diabetes as well.
Interventions Planned
Dr Zhang explained that her research group has already published on the role of potentially modifiable factors — such as weight management, diet, or physical activity — on progression from gestational diabetes to type 2 diabetes, and they have a number of other investigations under way, including a look at lifestyle factors such as sleep quality and duration, and genetic factors, as well as trying to identify other biomarkers that are early predictors for type 2 diabetes.
In addition, "our findings support the recent call to action from the National Diabetes Education Program, which underlines the importance of postpartum weight management after GDM," she and her coauthors say.
Dr Bilous says that more studies into specific interventions in this patient population are required. "Now, we know that, in the non-GDM population from the Finnish Diabetes Prevention Program, lifestyle interventions can be very effective.
"Recently I was at the Diabetes UK conference, where…an initiative [was announced] across the UK to roll out a diabetes-prevention program nationally.
"I think a great place to start would be in women with GDM, and to really hone treatment interventions in them, because they are the ones who have the highest rates of developing type 2 diabetes," he explained.
Recently, new research from the Diabetes Prevention Program Outcomes Study (DPPOS) showed that metformin and lifestyle intervention reduced the risk for type 2 diabetes among women with a history of gestational diabetes.
This study was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health. NHS II was funded by research grants from the National Institutes of Health. The authors have reported they have no relevant financial relationships.
Diabetologia. Published online March 18, 2015. Article
Medscape Medical News © 2015 WebMD, LLC
Send comments and news tips to news@medscape.net.
Cite this: Diabetes Skyrockets With High BMI Plus Weight Gain After GDM - Medscape - Mar 23, 2015.
Comments