The goal of this study was to examine the role of specific indoor air contaminants identified as endocrine-disrupting chemicals (EDCs) in the prevalence of asthma and other respiratory symptoms and obesity.

A cross-sectional analysis was used with 815 participants from 20 schools in Porto, Portugal, corresponding to a total of 71 classroom assessments.

Respiratory symptoms were assessed, lung function and airway reversibility were evaluated by spirometry and airway inflammation was determined by exhaled nitric oxide measurement. BMI was also calculated. The concentrations of 13 volatile organic compounds and 2 aldehydes identified as EDCs were measured throughout 1 week. Principal component analysis (PCA) was used to assess the effects of co-exposure. Associations were analyzed using linear and logistic regression models.

More children with asthma and obesity were found in classrooms that had increased individual and combined ECD levels. Higher levels of hexane, styrene, cyclohexanone, butylated hydroxytoluene and 2-butoxyethanol were associated with obesity, and higher levels of cyclohexanone were associated with increased 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.

The findings support the role of EDCs in the development of asthma and obesity. Even low levels of indoor exposure to certain EDCs may have an impact on the risk of asthma, respiratory symptoms, and obesity.

This study supports the need to improve indoor air quality in schools to include decreasing EDC exposures. School are the occupational environment for most children and much has been written about the importance of indoor air quality in reducing respiratory symptoms. This report adds to our knowledge by describing the potential effects of specific pollutants that are EDCs in this regard.