Normal blood sugar levels in gestational diabetes may not reduce CVD risk

USA: Attaining normal blood sugar levels (normoglycemia) does not reduce the risk of midlife cardiovascular disease (CVD) in women with previous gestational diabetes (GD), reveals a recent study in the AHA journal Circulation. In light of the findings, screening women with prior GD for CVD becomes important.

Gestational diabetes leads to heightened risk and earlier onset of type 2 diabetes -- a strong risk factor for CVD. However, it remains unclear if attaining normal levels of blood sugar can improved the excess risk of CVD associated with GD history. The study by Erica P. Gunderson, Division of Research, Kaiser Permanente Northern California, Oakland, CA, and colleagues aimed to evaluate GD history and glucose tolerance after pregnancy associated with coronary artery calcification (CAC) in women -- a predictor of CVD clinical events and manifestation of atherosclerotic CVD.

For the purpose, the researchers extracted data from the CARDIA study (Coronary Artery Risk Development in Young Adults), US multicenter, community-based prospective cohort of young Black (50%) and White adults aged 18 to 30 years at baseline (1985–1986).

The sample included 1133 women without diabetes at baseline having ≥1 singleton births (n=2066) during followup. Glucose tolerance testing at baseline and up to 5 times during 25 years (1986–2011), GD status, and CAC measurements obtained from 1 or more follow up examinations at years 15, 20, and 25 (2001–2011). CAC was measured by noncontrast cardiac computed tomography; dichotomized as Any CAC (score>0) or No CAC (score=0).  

"Women without previous GD showed a graded increase in the risk of CAC associated with worsening glucose tolerance. Women with a history of GD had a 2-fold higher risk of CAC across all subsequent levels of glucose tolerance," wrote the authors. 

"Midlife atherosclerotic CVD risk among women with previous GD is not diminished by attaining normoglycemia."

The study titled, "Gestational Diabetes History and Glucose Tolerance After Pregnancy Associated With Coronary Artery Calcium in Women During Midlife: The CARDIA Study," is published in the AHA journal Circulation.

DOI: https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.120.047320