Superfund Research Program
Biomarker Epidemiology of Exposure to Mixtures, Oxidative Stress, and Adverse Pregnancy Outcomes in Puerto Rico
Project Leader: John D. Meeker (University of Michigan)
Co-Investigators: Bhramar Mukherjee (University of Michigan), Deborah J. Watkins (University of Michigan)
Grant Number: P42ES017198
Funding Period: 2010-2025
Preterm birth is a major public health problem, especially in Puerto Rico. The Puerto Rico Testsite for Exploring Contamination Threats (PROTECT) study is an ongoing investigation of environmental factors that contribute to preterm birth. In this grant year the Biomarker Epidemiology of Exposure to Mixtures, Oxidative Stress, and Adverse Pregnancy Outcomes in Puerto Rico Project investigated the association between concentrations of metals and metalloids in maternal blood and adverse birth outcomes among 812 pregnant women participating in PROTECT. Blood metal(loid) concentrations were measured at two study visits (~ 20 and 28 weeks gestation), and the research team analyzed associations with gestational age at delivery and preterm birth among both individual metal(loids) and combinations/mixtures of these elements (Ashrap 2020). The researchers additionally assessed differences in associations by study visit and among preterm births with a spontaneous delivery. In adjusted models, an interquartile range (IQR) increase in lead (Pb) was associated with 1.63 higher odds of preterm birth (95 percent CI = 1.17, 2.28) and 2 days shorter gestational age (95 percent CI = -3.1, -0.5). Manganese (Mn) and zinc (Zn) were also associated with higher odds of preterm birth and shorter gestational age; the associations were strongest at the highest end of the distribution for Mn, and among females for Zn. Mercury (Hg) was associated with higher risk of preterm birth when measured at the later window of pregnancy (~28 weeks). The mixtures analysis also showed significant associations between combined exposure to multiple metal(loids) and preterm birth. The research findings suggest that low-level prenatal lead exposure, as well as elevated Mn and Zn exposure, may adversely affect birth outcomes.