Prenatal exposure to heavy metals and childhood atopic disease

Introduction: Our objective was to determine the relationship between biomarkers of exposure to eleven heavy metals measured at birth and atopic disease in offspring up to 5.5 years. Methods: Heavy metals were measured in women of the ELFE cohort from: maternal urine (n = 804; arsenic [As], cadmium [Ca], cesium [Cs], chromium [Cr], cobalt [Co], nickel [Ni], antimony [Sb], tin [Sn] and vanadium [V]), hair (n = 1649; mercury [Hg]), and cord blood (n = 1525; lead [Pb]) collected at birth. Data on atopic diseases (eczema, food allergy, wheezing, asthma, and rhinitis) were collected from 2 months to 5.5 years. Five multimorbidity clusters were previously identified using latent class analysis: "asymptomatic", "early wheeze without asthma", "allergies without asthma", "asthma only", and "multimorbidity". Multinomial logistic regression was performed, using the asymptomatic cluster as the reference, to determine the relationship between heavy metal concentrations and atopic diseases. Results: Concentrations of Co were negatively associated with the multimorbidity cluster in the whole sample (OR 0.66 [95% CI 0.49, 0.89]). In boys, Cs was associated with lower odds of belonging to the early wheeze without asthma (0.71 [0.52, 0.97]) and multimorbidity clusters (0.54 [0.35, 0.82), while Sn was negatively associated with the multimorbidity cluster (0.66 [0.46, 0.96]). Results with binary outcomes supported findings from cluster analyses. Conclusion: Exposure to some heavy metals assessed at delivery was inversely associated with the risk of atopic diseases, especially among boys. Further research should focus on heavy metal subtypes to distinguish between the more and less toxic forms.