Work

Fractional exhaled nitric oxide (FeNO) among elementary school children in Stockholm: Associations with asthma, allergies, and home and school environment

Year: 2025

Type: article

Abstract: Few studies have investigated links between fraction exhaled nitric oxide (FeNO), the home and the school environment. FeNO is a biomarker of T helper 2 (Th2) airway inflammation. We investigated associations between FeNO and airway symptoms, allergies, household and classroom exposure among pupils in ten primary schools in Stockholm ( N = 415). Information on health and household environment was obtained by a questionnaire. FeNO was measured at school. Particle mass (PM 1 , PM 2.5 , PM 10 ), carbon dioxide (CO 2 ), temperature, and relative air humidity (RH) were measured in the classrooms. Microbial DNA and 3-hydroxy fatty acids (3-OHs) from endotoxin in Gram-negative bacteria were analysed in vacuumed dust from floors and upper surfaces. Three-level linear mixed models were used to analyse associations. In total, 9.7 % of the pupils had elevated FeNO (>20 ppb), 15.2 % doctor diagnosed asthma, 10.7 % current asthma, 17.8 % reported allergy and 9.6 % doctor diagnosed allergy. Reported allergy ( p = 0.02), diagnosed allergy ( p = 0.002), and current asthma ( p = 0.007) were associated with elevated FeNO. Children living in single-family houses with basement had higher FeNO than those in self-owned apartments ( p = 0.001). In the classrooms, PM 10 ( p = 0.008), RH ( p = 0.004) and DNA copies from Gram-negative bacteria in vacuumed floor dust (p = 0.008) were associated with higher FeNO. C16 3-OH in floor dust ( p = 0.046) and C10 ( p = 0.02) and C11 3-OHs (p = 0.04) in upper surface dust were associated with higher FeNO. The association between Gram-negative bacteria at school and FeNO was stronger among girls. Children with parental asthma and allergy, and among those with dampness and mould at home and in single-family houses with basement. FeNO is associated with reported asthma and allergy. In the school environment, PM 10 and exposure to some subpopulations of Gram-negative bacteria can increase FeNO. Sex, parental asthma or allergy, dampness at home and type of housing can modify associations between classroom exposure and FeNO. • Exposure to some subpopulations of Gram-negative bacteria at school can increase FeNO • Particle mass concentration (PM10) in the classroom air may increase FeNO • Living in single-family homes with a basement can be associated with elevated FeNO • Dampness at home can enhance the association between endotoxin at school and FeNO • Gender and heredity can modify the associations between school exposure and FeNO

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2025.179113