The role of obesity in the risk of gestational diabetes among immigrant and U.S.-born women in New York City

Purpose: To examine if the role of obesity in the risk of gestational diabetes differs between immigrant and U.S.-born women. Methods: We used New York City–linked 2010–2014 birth certificate and hospital data. We created four racial/ethnic groups (non-Hispanic black, Hispanic, non-Hispanic white, and Asian) and three subgroups (Mexican, Indian, and Chinese). Gestational diabetes mellitus (GDM) was ascertained by the birth certificate checkbox and discharge ICD-9 codes. We calculated relative risks for immigrant status and body mass index with GDM using covariate-adjusted log-binomial regression. We calculated multivariable population attributable risk to estimate the proportion of GDM that could be eliminated if overweight/obesity were eliminated by immigrant status. Results: Immigrant women had higher risk of GDM than U.S.-born women, with adjusted relative risks ranging from 1.2 among non-Hispanic black women (95% confidence interval, 1.2–1.3) to 1.6 among Hispanic women (95% confidence interval, 1.4–1.8). Increasing body mass index was associated with GDM risk in all groups, but relative risks were weaker among immigrants (P for interaction <.05). The population attributable risk for overweight/obesity was lower in immigrant women than in U.S.-born women in all racial/ethnic groups. Conclusions: The lower proportion of GDM attributable to overweight/obesity among immigrant women may point to early life and migration influences on risk of GDM.