Study Examines Prevalence, Drivers of Racial Disparities in T2D Following Gestational Diabetes

Teresa Janevic, PhD
Credit: LinkedIn

New research published in Obstetrics & Gynecology describes substantial population-based racial and ethnic inequities in type 2 diabetes after gestational diabetes mellitus.

Results of the study, which examined trends in type 2 diabetes prevalence following gestational diabetes mellitus among more than 22,000 women, suggest the 8-year incidence rate of type 2 diabetes in adjusted analyses was more than 3 times greater among Black and Hispanic women as compared to their White counterparts.¹

“Very few studies have examined prenatal, social, or structural determinants of type 2 diabetes after GDM,” said Teresa Janevic, PhD, associate professor of Epidemiology at Columbia University Mailman School of Public Health.² “Our study has several strengths. It is the largest cohort study to date on racial and ethnic disparities after GDM, allowing us to explore potential pathways to these disparities.”

Led by Janevic, along with colleagues from the Icahn School of Medicine at Mount Sinai and the University of Pennsylvania, the current study was launched with the intent of estimating racial and ethnic disparities in type 2 diabetes mellitus after gestational diabetes mellitus as well as investigating potential mediating factors, including baseline pregnancy clinical and social or structural characteristics. To do so, investigators designed their research endeavor as a retrospective cohort study leveraging linked registry records for all 2009–2011 New York City births with 2009–2017 A1c Registry data¹

Named the A1c in Pregnancy and Postpartum Linkage for Equity (APPLE) study, the 8-year retrospective cohort included 22,853 pregnancies in New York City. Of the 22,853 women included in the study, 20.5% were Black, 11.0% were East and Central Asian, 30.9% were Hispanic, 10.9% were South and Southeast Asian, and 18.5% were White.¹

For the purpose of analysis, the primary outcome of interest was the prevalence of type 2 diabetes among different racial and ethnic subgroups. Investigators defined type 2 diabetes as having at least 2 HbA1c test results of 6.5% or greater. Investigators pointed out Cox proportional hazards models were used to estimate associations between race and ethnicity and 8-year type 2 diabetes incidence.¹

Upon analysis, the cumulative incidence of type 2 diabetes was 11.7% among the entire study cohort by the end of the 8-year follow-up. The examining incidence rate by race and ethnicity, the greatest incidence was observed among Black individuals at 18.5% followed by 16.8% for South and Southeast Asian individuals, 14.6% for Hispanic individuals, 5.5% for East and Central Asian individuals, and 5.4% for White individuals. In analyses adjusted for age and nativity, an increased risk of type 2 diabetes incidence was observed for Black (adjusted Hazard Ratio [aHR], 4.0; 95% Confidence Interval [CI], 2.4-3.9), South and Southeast Asian (aHR, 3.3; 95% CI, 2.7-4.2), and Hispanic (aHR, 2.9; 95% CI, 2.4-3.3) individuals relative to their White counterparts.¹

Further analysis indicated combined clinical and social or structural factors explained the largest percentage of the association between race and ethnicity on type 2 diabetes among (45.8%, 95% CI, 28.6-58.0) followed by Black (26.7%, 95% CI 11.5–32.5%) individuals. However, investigators noted these combined mediators only explained 14.1%(95% CI, 3.9-24.8) of the association among South and Southeast Asian individuals.¹

“Our findings underscore the opportunity for GDM as an intervention point for life-course type 2 diabetes inequities and stress the importance of racial and ethnic disparities in GDM outcomes beyond the current pregnancy,” Janevic added.² “We call for further work using multiple approaches – policy-level changes, along with clinical interventions targeting individuals, — to counter structural racism and to eliminate disparities.”

References:

Janevic T, McCarthy K, Liu SH, et al. Racial and Ethnic Inequities in Development of Type 2 Diabetes After Gestational Diabetes Mellitus [published online ahead of print, 2023 Sep 7]. Obstet Gynecol. 2023;10.1097/AOG.0000000000005324. doi:10.1097/AOG.0000000000005324

Columbia University Mailman School of Public Health. Study seeks to explain widespread inequality for developing diabetes mellitus following gestational diabetes. Columbia University Mailman School of Public Health. September 8, 2023. Accessed September 11, 2023. https://www.publichealth.columbia.edu/news/study-seeks-explain-widespread-inequality-developing-diabetes-mellitus-following-gestational-diabetes.