Association between prenatal metal exposure and respiratory symptoms in childhood

Abstract

BACKGROUND AND AIM: Arsenic, manganese, and lead have been cross-sectionally associated with adverse respiratory outcomes in childhood but there is limited data on their combined effects starting in utero. Our aim was to examine associations between prenatal lead, arsenic, and manganese exposure and respiratory symptoms in childhood. METHODS: We assessed 637 mother-child dyads enrolled in the Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) birth cohort in Mexico City. Blood manganese (BMn), arsenic (BAs), and lead (BPb) were measured in mothers at 2nd trimester. Ever wheeze, current wheeze and asthma diagnosis was based on the caregiver’s answers (yes/no) from the International Study of Asthma and Allergies in Childhood (ISAAC) survey applied at 4-5 and 6-7 years old. Covariates included maternal education, maternal asthma status, maternal age at enrollment, child’s sex, and prenatal environmental tobacco smoke exposure. A logistic mixed model regression was generated to simultaneously assess the association between prenatal metals and ever wheeze, current wheeze, and asthma diagnosis longitudinally across both the 4-5 and 6-7 year study visits. RESULTS:The mean ± standard deviation for log-transformed BMn, BPb, and BAs at 2nd trimester were 0.14 µg/dL ± 0.15, 0.48 µg/dL ± 0.27, and -1.11 µg/dL ± 0.19, respectively. In the adjusted model, BPb (Odds Ratio (OR): 1.95, 95% CI: 1.04-3.66) and BAs (OR: 3.44, 95% CI: 1.05-11.34) at 2nd trimester were associated with increased odds of ever wheeze and current wheeze, respectively. BMn at 2nd trimester (OR: 0.05, 95% CI: 0.01-0.27) was negatively associated with current wheeze. CONCLUSIONS:Prenatal exposure to arsenic and lead was associated with higher odds of ever and current wheeze while manganese was negatively associated with odds of current wheeze in childhood. These findings underscore the need to consider prenatal metal exposure, including low levels of exposure, in the study of respiratory diseases. KEYWORDS: Respiratory outcomes, Heavy metals, Allergies, Asthma, Children's environmental health