ABSTRACT
Allergic disease is still a serious global public health problem, affecting 30-40% of world population. The rapid increase in prevalence indicates gene-by-environment interaction, in which epigenetics may be the underlying mechanism. We reviewed recent epidemiological studies about the association between prenatal exposure to air pollution and childhood allergies. On the other hand, we reviewed the evidence that maternal exposure to air pollution caused epigenetic alterations that changed the gene expression or transcription in offspring. We further discussed the challenges of the global warming and COVID-19 to the childhood allergies especially in developing countries, and suggested the opportunities to prevention or control by early intervention, immunotherapy, and epigenetic therapy.
ABSTRACT
BACKGROUND: Quaternary ammonium compounds (QACs), commonly used in cleaning, disinfecting, and personal care products, have recently gained worldwide attention due to the massive use of disinfectants during the COVID-19 pandemic. However, despite extensive use of these chemicals, no studies have focused on the analysis of QACs in human milk, a major route of exposure for infants. OBJECTIVE: Our objectives were to identify and measure QACs in breast milk and evaluate early-life exposure to this group of compounds for nursing infants. METHODS: Eighteen QACs, including 6 benzylalkyldimethyl ammonium compounds (BACs, with alkyl chain lengths of C8-C18), 6 dialkyldimethyl ammonium compounds (DDACs, C8-C18), and 6 alkyltrimethyl ammonium compounds (ATMACs, C8-C18), were measured in breast milk samples collected from U.S. mothers. Daily lactational intake was estimated based on the determined concentrations for 0-12 month old nursing infants. RESULTS: Thirteen of the 18 QACs were detected in breast milk and 7 of them were found in more than half of the samples. The total QAC concentrations (ΣQAC) ranged from 0.33 to 7.4 ng/mL (median 1.5 ng/mL). The most abundant QAC was C14-BAC with a median concentration of 0.45 ng/mL. The highest median ΣQAC estimated daily intake (EDI) was determined for <1-month old infants based on the average (using the median concentration) and high (using the 95th percentile concentration) exposure scenarios (230 and 750 ng/kg body weight/day, respectively). SIGNIFICANCE: Our findings provide the first evidence of the detection of several QACs in breast milk and identify breastfeeding as an exposure pathway to QACs for nursing infants. IMPACT STATEMENT: Our findings provide the first evidence of QAC occurrence in breast milk and identify breastfeeding as one of the exposure pathways to QACs for nursing infants.