Background:

The American College of Obstetricians and Gynecologists recommends early screening for gestational diabetes mellitus among pregnant Asian people with a prepregnancy body mass index ≥23.0 kg/m², in contrast with the recommended screening at a body mass index ≥25 kg/m² for other races and ethnicities. However, there is significant heterogeneity within Asian and Pacific Islander populations, and gestational diabetes mellitus and its association with body mass index among Asian and Pacific Islander subgroups may not be uniform across all groups.

Objective:

This study aimed to analyze the association between body mass index and gestational diabetes mellitus among Asian and Pacific Islander subgroups in California, specifically gestational diabetes mellitus rates among those with a body mass index above vs below 23 kg/m², which is the cutoff point for the designation of being overweight among Asians populations.

Study design:

Using a linked delivery hospitalization discharge and vital records database, we identified patients who gave birth in California between 2007 and 2017 and who self-reported to be 1 of 13 Asian and Pacific Islander subgroups, which was collected from birth and fetal death certificates. In each subgroup, we evaluated the association between body mass index and gestational diabetes mellitus using multivariable logistic regression models adjusted for age, education, parity, payment method, the trimester in which prenatal care was initiated, and nativity. We fit body mass index nonlinearly with splines and categorized body mass index as being above or below 23 kg/m². Predicted probabilities of gestational diabetes mellitus with 95% confidence intervals were calculated across body mass index values using the nonlinear regression models.

Results:

The overall prevalence of gestational diabetes mellitus was 14.3% (83,400/584,032), ranging between 8.4% and 17.1% across subgroups. The highest prevalence was among Indian (17.1%), Filipino (16.7%), and Vietnamese (15.5%) subgroups. In these subgroups, gestational diabetes mellitus was diagnosed in 10% to 13% of those with a body mass index <23.0 kg/m² and in 22% of those with a body mass index ≥23 kg/m². Gestational diabetes mellitus was least common among Korean (8.4%), Japanese (9.0%), and Samoan (9.8%) subgroups with a gestational diabetes mellitus rate of 5% to 7% among those with a body mass index <23.0 kg/m² and in 10% to 15% among those with a body mass index ≥23 kg/m². Although Samoan patients had the highest rate of obesity, defined as body mass index ≥30 kg/m² (57.4%), they had the third lowest prevalence of gestational diabetes mellitus. Conversely, Vietnamese patients had the second lowest rate of obesity (2.4%) but the highest rate of gestational diabetes mellitus at a body mass index of ≥23 kg/m² (22.3%).

Conclusion:

Gestational diabetes mellitus and its association with body mass index varied among Asian subgroups but increased as body mass index increased. Subgroups with the lowest prevalence of obesity trended toward a higher prevalence of gestational diabetes mellitus and those with a higher prevalence of obesity trended toward a lower prevalence of gestational diabetes mellitus.