A Cohort Study of a History of Gestational Diabetes Mellitus and the Risk of Incident Type 2 Diabetes in Louisiana Women

Abstract

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications. It has been shown that a history of GDM is associated with an increased risk of incident type 2 diabetes in women. In this project, we aim to investigate 1) the trend of GDM incidence in Louisiana State University Health Care Services Division (LSUHCSD) hospital system during 1997 to 2009; 2) the race-specific association between a history of GDM and the risk of incident type 2 diabetes and how the risk changes over years after the index pregnancy. We conducted a retrospective study among women aged 13-50 years. Pregnancies, GDM cases and type 2 diabetes cases were identified by using the International Classification of Disease (ICD) -9 code from the Louisiana State University Hospital-Based Longitudinal Study (LSUHLS) database. The annual incidence of GDM and it standard error (SE) were calculated. Cox proportional hazards regression models were used to estimate the association of a history of GDM with the risk of incident type 2 diabetes. The association between previous GDM and the risk of type 2 diabetes in different postpartum periods was examined using logistic regression. The incidence of GDM increased in most years from 1997 to 2009 and reached a peak in 2002. The incidence of GDM increased with age and reached the peak at 35-39 years of age. Among the three study races, Asians had a significantly higher incidence of GDM than Whites and African Americans. Between 1990 and 2009, 1,142 GDM women and 18,856 non-GDM women presented their first record of pregnancy in the LSUHLS database. During a mean follow-up of 8.6 years, 1,067 women without a history of GDM and 327 women with a history of GDM developed type 2 diabetes. The multivariable-adjusted (age, smoking, income, postpartum body mass index (BMI), postpartum systolic blood pressure, and race) hazard ratio of type 2 diabetes suggested that a history of GDM is a strong predictor of subsequent type 2 diabetes among Louisiana women, especially among African American women. In addition, risk of type 2 diabetes was decreased by the time after the index delivery.