Women who experience gestational diabetes may face an increased risk of early heart disease later in life, even if they do not develop type 2 diabetes or metabolic syndrome subsequent to their pregnancy, according to a Kaiser Permanente study published in the Journal of the American Heart Association.
"Our research shows that just having a history of gestational diabetes elevates a woman's risk of developing early atherosclerosis before she develops type 2 diabetes or metabolic syndrome," said Erica P. Gunderson, PhD, MPH, study lead author and senior research scientist in the Kaiser Permanente Division of Research in Oakland, Calif. "Pregnancy has been under-recognized as an important time period that can signal a woman's greater risk for future heart disease. This signal is revealed by gestational diabetes."
Gestational diabetes, a condition of elevated blood sugar during pregnancy, usually disappears after the pregnancy. It is managed with meal planning, activity and sometimes insulin or other medications.
In the 20-year study, researchers assessed risk factors for heart disease before pregnancy among 898 women, 18 to 30 years old, who later had one or more births. The women were periodically tested for diabetes and metabolic conditions before and after their pregnancies. Using ultrasound, researchers measured the thickness of the walls of participants' carotid artery, which circulates blood to the neck and face. Carotid artery wall thickness is an early measure of atherosclerosis — plaque build-up in arteries — and predicts heart attack and stroke in women. The artery's thickness was measured on average 12 years after pregnancy.
Researchers found a larger average carotid artery wall thickness in study participants with a history of gestational diabetes who did not develop diabetes or metabolic syndrome during the 20-year follow-up compared to those who never experienced gestational diabetes. The difference was not attributed to obesity or other risk factors for heart disease that were measured before pregnancy.
It's important to recognize reproductive characteristics that may contribute to disease risk in women, Gunderson said. "It's a shift in thinking about how to identify a subgroup at risk for atherosclerosis early. The concept that reproductive complications unmask future disease risk is a more recent focus. It may inform early prevention efforts."
This study is part of Kaiser Permanente's ongoing efforts to better understand gestational diabetes. Last year, Kaiser Permanente researchers found that pre-pregnancy obesity and older maternal age are among the risk factors for delayed lactation for women with gestational diabetes.
Kaiser Permanente can conduct transformational health research in part because it has the largest private patient-centered electronic health system in the world. That system, Kaiser Permanente HealthConnect®, securely connects 9.1 million patients to more than 16,000 physicians in nearly 600 medical offices and 38 hospitals. It also connects Kaiser Permanente's research scientists to one of the most extensive collections of longitudinal medical data available, facilitating studies and important medical discoveries that shape the future of health and care delivery for patients and the medical community.
Other authors on the study include Vicky Chiang, MSPH, Charles P. Quesenberry, Jr., PhD, and Stephen Sidney, MD, of the Kaiser Permanente Division of Research, Oakland, Calif.; Mark J. Pletcher, MD, MPH, of the Department of Epidemiology and Biostatistics, University of California, San Francisco; David R. Jacobs, Jr., PhD, of the Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis; and Cora E. Lewis, MD, MSPH, of the Division of Preventive Medicine, University of Alabama at Birmingham.
This research was funded in part by the National Institutes of Health (K01 DK059944).