The influence of demographic and phenotypic heterogeneity on the prevalence of gestational diabetes mellitus

In order to explore the influence of demographic and phenotypic characteristics on the prevalence of gestational diabetes mellitus (GDM), data were analyzed from 3744 consecutive patients who underwent universal screening with a 50 g glucose load at 24-28 weeks gestational age. Those with a 1-h plasma glucose ≥130 mg/dl underwent a 3-h, 100-g oral glucose tolerance test following dietary preparation. The population was 39.1% White, 37.7% Black, 19.8% Hispanic and 3.4% Oriental/other. The overall prevalence of GDM was 3.5 cases/100. Significant inter-racial differences in maternal age and prepregnant percent ideal body weight (PIBW) were observed, with White patients being older and leaner than Blacks and Hispanics. By multiple logistic regression, Black and Hispanic race, maternal age and PIBW were found to have significant independent effects on the prevalence of GDM. Controlling for age and PIBW, the adjusted relative risk of GDM was significantly higher in Black (1.81, 95% CI 1.13-2.89) and Hispanic (2.45, 95% CI 1.48-4.04) patients compared to White. We conclude that demographic and phenotypic characteristics of populations need to be taken into consideration in future studies of prevalence of GDM, perinatal implications and therapeutic approaches to the disease.