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Background: The extent to which ambient air pollution contributes to the pathogenesis of congenital heart defects remains uncertain. Objective: We investigated whether first trimester exposure to ambient fine particulate matter (P[M.sub.2.5]) and nitrogen dioxide (N[O.sub.2]) was associated with the risk of critical and noncritical heart defects in a large population-based cohort of births. Methods: We carried out a retrospective cohort study of children conceived between 2000 and 2016 in Quebec, Canada. Heart defects were identified via data from the Maintenance and Use of Data for the Study of Hospital Clientele registry. The main exposures were average concentration of P[M.sub.2.5] and N[O.sub.2] in a) the first trimester and b) the month of conception. Exposures were estimated at the residential postal code. Associations with critical and noncritical heart defects were assessed using logistic regression models, adjusted for maternal and infant characteristics. We considered single- and two-pollutant models and assessed modifying effects of maternal comorbidity, including preexisting hypertension, preeclampsia, anemia, and diabetes. Results: The cohort comprised 1,342,198 newborns, including 12,715 with heart defects. Exposure in the first trimester and month of conception yielded similar results; both were associated with a greater risk of heart defects. Adjusted odds ratios (OR) for any heart defect per interquartile range increase were 1.02 (95% CI: 1.00, 1.05) forP[M.sub.2.5] and 1.10 (95% CI: 1.07, 1.13) for N[O.sub.2]. Associations with atrial septal defects were 1.08 (95% CI: 1.03,1.14) forP[M.sub.2.5] and 1.19 (95% CI: 1.12, 1.25) for N[O.sub.2]. Corresponding ORs for ventricular septal defects and individual critical heart defects were not significant. P[M.sub.2.5] (OR = 1.11; 95% CI: 1.06, 1.17) and N[O.sub.2] (OR = 1.23; 95% CI: 1.17, 1.31) exposure were associated with a greater risk of heart defects in mothers with comorbidity. Discussion: In this population-based cohort, prenatal exposure to ambient air pollution during the first trimester was associated with an increased risk of heart defects, particularly atrial septal defects. The association with heart defects was greater in mothers with comorbidity. https://doi.org/10.1289/EHP11120, Introduction Congenital heart anomalies are prevalent and account for nearly one-third of birth defects. (1) In North America, 1.5% of newborns have heart defects. (2) Heart defects are a leading [...]

Background: Environmental factors may contribute to the development of Kawasaki disease in children, but prenatal environmental exposures are understudied. Objective: We used a population-based cohort to investigate whether prenatal exposure to outdoor air pollution is associated with the incidence of Kawasaki disease in childhood. Methods: We performed a longitudinal cohort study of all children born in Quebec, Canada, between 2006 and 2012. Children were followed for Kawasaki disease from birth until 31 March 2018. We assigned prenatal air pollutant exposure according to the residential postal code at birth. The main exposure was annual average concentration of ambient fine particulate matter [PM [less than or equal to]2.5 [micro]m in aerodynamic diameter (P[M.sub.2.5]) and nitrogen dioxide (N[O.sub.2]) from satellite-based estimates and land-use regression models. As secondary exposures, we considered industrial P[M.sub.2.5], N[O.sub.2], and sulfur dioxide (S[O.sub.2]) emissions estimated from dispersion models. We estimated hazard ratios (HRs) using Cox proportional hazards models, adjusted for maternal age, parity, sex, multiple birth, maternal smoking during pregnancy, socioeconomic status, birth year, and rural residence. We considered single and multipollutant models. We performed several sensitivity analyses, including assessing modifying effects of maternal comorbidities (e.g., diabetes, preeclampsia). Results: The cohort comprised 505,336 children, including 539 with Kawasaki disease. HRs for each interquartile range increase in ambient air pollution were 1.16 (95% CI: 0.96, 1.39) for P[M.sub.2.5] and 1.12 (95% CI: 0.96, 1.31) for N[O.sub.2]. For industrial air pollution, HRs were 1.07 (95% CI: 1.01, 1.13) for S[O.sub.2], 1.09 (95% CI: 0.99, 1.20) for N[O.sub.2], and 1.01 (95% CI: 0.97, 1.05) for P[M.sub.2.5]. In multipollutant models, associations for ambient P[M.sub.2.5] and N[O.sub.2] (i.e., from all sources) were robust to adjustment for industrial pollution, and vice versa. Discussion: In this population-based cohort study, both prenatal exposure to ambient and industrial air pollution were associated with the incidence of Kawasaki disease in childhood. Further studies are needed to consolidate the observed associations. https://doi.org/10.1289/EHP6920, Introduction Kawasaki disease is the leading cause of acquired heart disease in children in North America (Kawasaki Disease Canada 2020; McCrindle et al. 2017). Kawasaki is an autoimmune vasculitis, mostly [...]

Because quarterly concentrations of total trihalomethanes (THM) exceeding the 80 μg/L guideline are often tolerated by the public health authorities of the Province of Quebec (Canada), this study examined whether quarterly episodes of high concentrations of THM may pose a risk to the health of its population. Using Monte Carlo simulations, a probabilistic risk assessment was performed for infants (0-<6 mo), toddlers (6 mo-<5 yr) and adults (≥20 yr). Multiroute exposure including ingestion of drinking water as well as inhalation and dermal exposure while showering or bathing was considered. The resulting absorbed doses were compared to short-term reference values for chloroform, used as surrogate for THM, by calculating risk quotients (RQ). On the basis of THM concentrations values in Quebec's drinking water distribution systems during the months of July to October and exceeding the guideline value (>80 μg/L), the 95th percentile value of RQ were 0.65, 0.46, and 0.24 for infants, toddlers, and adults, respectively. Back-calculation allowed determining that a chloroform concentration of 330 μg/L would result in RQ ≤ 1 for 99% of infants, the subgroup considered the most susceptible among the general population. Overall, this study showed that episodes of high THM concentration encountered in Quebec drinking-water distribution network need not be considered as an immediate health concern for the general population. However, these results should not be interpreted as an authorization to exceed the 80 μg/L standard but rather as a risk management tool for public health authorities. [ABSTRACT FROM AUTHOR]