1263-P: Associations of Metal and Element Mixture with Gestational Diabetes Mellitus (GDM) in a Racially and Ethnically Diverse U.S. Birth Cohort—A Bayesian Kernel Machine Regression (BKMR) Analysis

Introduction and Objective: Metals may increase the risk of GDM, while certain elements may be protective. We examined the associations of a mixture of metals and elements during pregnancy with GDM risk in a predominantly Black and Hispanic cohort. Methods: In the Boston Birth Cohort, we measured Pb, Hg, Cd, Se, and Mn in maternal red blood cells collected postpartum. GDM cases were identified using ICD codes and plasma glucose profiles. Women with pre-existing diabetes were excluded. We used modified Poisson regression to assess individual associations and probit BKMR to assess mixture effects. Results: Among 1,256 women (58% Black, 22% Hispanic; median age 27.9y), Black women had higher Pb and Hg levels than Hispanic or White women (Panel A). A doubling of Hg and Mn was associated with 1.16 (95% CI: 1.03-1.31) and 0.65 (95% CI: 0.50-0.86) times the GDM risk, respectively (Panel B). Se showed a trend toward higher GDM risk. Associations of Hg and Mn with GDM did not vary by race. BKMR showed non-linear associations for Hg and linear ones for Se and Mn with GDM (Panel C) and did not identify exposure interactions. Conclusion: Women with higher Hg or lower Mn levels during pregnancy were more likely to develop GDM. Future research should explore interventions to mitigate the effects of prior Hg exposure or increase pregnancy Mn levels. Z. Li: None. G. Wang: None. X. Hong: None. S.P. Juraschek: None. L.H. Ngo: None. M. Zhang: None. American Diabetes Association (7-24-ICTSWH-10); National Institutes of Health (2R01HD041702, R01HD098232, R01ES031272, R01ES031521, and U01ES034983)