Exposure to indoor endocrine‐disrupting chemicals and childhood asthma and obesity

Background Indoor air contaminants may act as endocrine‐disrupting chemicals (EDCs). However, to what extent these contaminants affect health is poorly known. We aimed to assess the association between EDCs exposure and asthma, respiratory symptoms and obesity in schoolchildren. Methods Data from a cross‐sectional analysis of 815 participants from 20 schools in Porto, Portugal, were analysed. Symptoms were assessed, asthma was defined on lung function, and airway reversibility and body mass index (BMI) were calculated. The concentrations of 13 volatile organic compounds and 2 aldehydes identified as EDCs were measured in 71 classrooms throughout 1 week. Principal component analysis (PCA) was used to assess the effect of co‐exposure. Associations were estimated by regression coefficients using linear and logistic regression models. Results Increased individual and combined EDCs levels were found in classrooms having more children with asthma and obesity. Higher levels of hexane, styrene, cyclohexanone, butylated hydroxytoluene and 2‐butoxyethanol were associated with obesity, and higher levels of cyclohexanone were associated with increased child BMI. Toluene, o‐xylene, m/p‐xylene and ethylbenzene were significantly associated with nasal obstruction. A positive association was found between PC1 and the risk of obese asthma (OR = 1.43, 95% CI 1.01, 1.98) and between PC2 and overweight (OR = 1.51, 95% CI 1.28, 1.79). PC1 and PC2 were also associated with nasal obstruction, and PC2 was associated with breathing difficulties and lean body mass, although EDCs concentrations were low. Conclusions Our findings further support the role of EDCs in asthma and obesity development. Moreover, even low levels of indoor exposure may influence the risk of asthma, respiratory symptoms and obesity. Exposure to low levels of EDCs have an effect on asthma, current symptoms and obesity in school‐age children. Individual or combined EDCs also associate with ANS changes, that may possibly mediate the interaction between EDCs and childhood asthma and obesity. Our findings may contribute to action plans to reduce exposures to EDCs and to promote a healthy indoor school environment.ANS: autonomic nervous system; BHT: butylated hydroxytoluene; EDCs: endocrine‐disrupting chemicals; The circles represent the Odds ratio (OR) values, being the size proportional do the OR.Circles: OR 1.*Positive bronchodilatation; **Obese asthma; ┴ Nasal obstruction; ┴ ┴ Breathing difficu