Racial differences of incident diabetes postpartum in women with a history of gestational diabetes.

AIMS: The aim of the present study was to investigate the race-specific association between a history of gestational diabetes mellitus (GDM) and incidence of type 2 diabetes and evaluate how the risk changed over different years after delivery.

METHODS: We performed two large cohorts - the Coronary Artery Risk Development in Young Adults (CARDIA) cohort and the Tianjin GDM Observational Study. The multivariate cox regression model was used to assess the risk of incident postpartum diabetes between women with and without prior GDM.

RESULTS: During a mean follow-up of 13.8 years, 405 women developed type 2 diabetes. After adjustment for multiple confounding factors, Chinese women with GDM had a higher risk of incident diabetes within 5 years postpartum than African Americans with GDM compared with Chinese and African Americans without GDM (Hazard ratio 71.5 in Chinese vs. 9.29 in African Americans). When the risk of incident diabetes was analyzed within 10 years, white women with GDM seemed to have a higher hazard ratio than African American and Chinese women with GDM compared with non-GDM women of different races. In comparison to African American women without GDM, the highest risk of type 2 diabetes over 10 years postpartum appeared in Chinese women with GDM, followed by African American women with GDM, and the smallest risk was seen in white women with GDM.

CONCLUSIONS: Different genetic backgrounds and other risk factors among women of different races might contribute to the racial differences in the incidence of diabetes postpartum among women with GDM.