Gestational Diabetes Linked to Coronary Artery Calcification, Regardless of Post-Birth Glucose Control

Erica Gunderson, PhD, MS, MPH

New data from an analysis of the CARDIA study reveal women with gestational diabetes were at an increased risk of cardiovascular disease later in life, even if their blood glucose levels returned to normal.

Results of the study provide evidence that women with prediabetes were not only at increased risk of developing prediabetes or type 2 diabetes later in life, but also indicated they were at a 2-fold increase in risk for coronary artery calcification even if they achieved normal blood sugar levels post-pregnancy.

“Women with previous gestational diabetes had a twofold higher risk of coronary artery calcium if they maintained normal blood sugar levels, later developed prediabetes, or later were diagnosed with Type 2 diabetes many years after pregnancy compared to women without previous gestational diabetes who had normal blood sugar levels," said Erica P. Gunderson, PhD, MS, MPH, epidemiologist and senior research scientist in the Cardiovascular and Metabolic Conditions Section at Kaiser Permanente's Division of Research in Oakland, California, in a statement.

While many studies have examined risks associated with gestational diabetes, an existing knowledge gap remains in relation to how achieving normoglycemia can influence risk of cardiovascular disease later in life. With this in mind, investigators conducted a retrospective analysis to assess how presence of gestational diabetes and glucose tolerance following pregnancy is associated with coronary artery calcification.

The investigators’ used data from the Coronary Artery Risk Development in Young Adults (CARDIA) study. A multicenter, longitudinal observational study, CARDIA enrolled more than 5000 participants from 4 geographic areas across the US in 1985-1986 and followed these patients for 25 years. Of the 2787 women included in CARDIA, 1392 had 1 or more post-baseline births and were identified for inclusion in the current analysis.

Women from the cohort of 2787 women were eliminated based on presence of multifetal gestations, overt diabetes at baseline, diabetes before a first postbaseline birth, no CAC measurements, or CAC measured only before postbaseline births. Additionally, all patients were required to have data related to glucose tolerance testing at baseline and up to 5 times during the 25-year follow-up and CAC measurements obtained from 1 or more follow-up examinations at years 15, 20, and 25. In total, 1133 women who had 2066 singletons births were included in the study.

CAC measurements were performed using noncontrast cardiac computed tomography. For the purpose of analysis, CAC scores were classified as any CAC, which was a score greater than 1, or no CAC, which was a score of 0.

At the end of the follow-up period, the mean age of the 1133-patient cohort was 47.6 (SD, 4.8) years and 139 (12.3%) women reported gestational diabetes. Of note, women who reported gestational diabetes were more likely to develop prediabetes or incident diabetes than maintain normoglycemia following pregnancy (36%, 25.9%, or 38.1%) when compared to women with no gestational diabetes (35%, 9%, or 56%, respectively) (P for all <.001).

In total, 183 (16.2%) of the entire study cohort had a CAC score greater than 0. Of the 139 women who reported gestational diabetes, 24.5% had a CAC score greater than 0 compared to 15% of the group with no gestational diabetes (P=.005). Investigators noted the portion of women with CAC did not vary by glucose tolerance categories among those with gestational diabetes (P=.65) but increased with worsening glucose control among women without gestational diabetes (P=.003).

Specifically, adjusted analyses produced hazard ratios of 1.54 (1.06–2.24) for no gestational/prediabetes and 2.17 (1.30–3.62) for no gestational diabetes/incident diabetes, and 2.34 (1.34–4.09), 2.13 (1.09–4.17), and 2.02 (0.98–4.19) for gestational diabetes/normoglycemia, gestational diabetes/prediabetes, and gestational diabetes/incident diabetes, respectively, when compared to those with no gestational diabetes and normoglycemia during follow-up.

"Risk assessment for heart disease should not wait until a woman has developed prediabetes or type 2 diabetes," Gunderson said. "Diabetes and other health problems that develop during pregnancy serve as early harbingers of future chronic disease risk, particularly heart disease. Health care systems need to integrate the individual's history of gestational diabetes into health records and monitor risk factors for heart disease, as well as the recommended testing for type 2 diabetes in these women at regular intervals, which is critical to target prevention efforts."

This study, “Gestational Diabetes History and Glucose Tolerance After Pregnancy Associated With Coronary Artery Calcium in Women During Midlife: The CARDIA Study,” was published in Circulation.