Associations of metal mixtures in early pregnancy with lung function and asthma in mid-childhood in Project Viva.

Whether fetal lung development may be vulnerable to gestational exposure to metals is unknown. We analyzed mother-child pairs in Project Viva, a prospective pre-birth cohort in eastern Massachusetts, USA. Concentrations of 11 essential and non-essential metals were measured in maternal first-trimester erythrocytes (~10 weeks). Measures of lung function were obtained by spirometry, and asthma status by recall, at the mid-childhood visit (~8 years). We fit both Bayesian hierarchical models (BHMs) with weakly informative priors, and conventional multivariable linear and logistic regressions (MLRs), to estimate associations of the metals with lung function and asthma. The analytic sample included 804 mother-child pairs (76.0% non-Hispanic White; 16.7% of children had current asthma). Each standard deviation (SD) increase in magnesium was associated with higher forced vital capacity (FVC) (mean difference: 26 mL, 95% credible interval (CrI); 5, 47), higher forced expiratory volume in 1 second (FEV1) (25 mL, 95% CrI: 6, 44), and lower odds of current asthma (odds ratio: 0.88, 95% CrI: 0.71, 1.1). BHMs provided more modest and precise estimates than MLRs. Our results suggest early pregnancy intake of magnesium may enhance fetal lung development, and may confer a modest reduction in the risk of asthma.