Effects of the Indoor Environment on the Fraction of Exhaled Nitric Oxide in School‐Aged Children

Abstract

BACKGROUND: The fractional concentration of exhaled nitric oxide (FeNO) appears to be a good marker for airway inflammation in children with asthma.OBJECTIVE: To evaluate the effect of environmental exposures on exhaled nitric oxide in a community sample of children.METHODS: The relationship among exhaled nitric oxide, underlying disease and home environmental exposures was examined using questionnaire data and measurement of exhaled nitric oxide in a cross-sectional study of 1135 children that included healthy children, and children with allergies and/or asthma who were attending grades 4 through 6 in Windsor, Ontario.RESULTS: Among healthy children, there was a positive association between FeNO and occupancy (P<0.02). Compared with forced air and hot water radiant heat, electric baseboard heating was associated with a significant increase of FeNO in healthy children (P=0.007) and children with allergies (P=0.043). FeNO was not associated with environmental tobacco smoke exposure or reported surface mold. The presence of pet dog(s), but not cats, was associated with a significantly lower FeNO in healthy children (P<0.001) and in children with reported allergies (P<0.001).CONCLUSIONS: The type of heating system, but not previously reported environmental tobacco smoke or mold exposure appears to affect exhaled nitric oxide in children. Exposure to different types of pets may have disparate effects on airway inflammation.

Exhaled NO: Determinants and Clinical Application in Children With Allergic Airway Disease

“…30 The authors speculated that forced air heating is associated with lower indoor dust mite levels, whereas electric heating increases indoor dust mite levels and is related to higher formaldehyde concentration, thus increasing the allergic sensitization and levels of FeNO. 31,32 In addition, there are 2 conflicting studies reporting the association between polyvinyl chloride material and FeNO levels.…”

“…The reported associations between smoking exposure and FeNO levels in asthmatic children have been discordant, probably due to methodological biases, such as small sample sizes, heterogeneous study populations, and lack of control for potential confounding factors. 30,35,36 Some studies have not found a significant effect of passive smoking on FeNO in children, 30,36 whereas others suggested that environmental tobacco smoke lowers FeNO levels (Table). 27,35 According to the type of smoke exposure, acute exposure may induce a marked, but transient reduction in FeNO levels related to a negative feedback of iNOS activity, since tobacco smoke contains high concentrations of NO.…”

Indoor Air Contaminants and Their Impact on Respiratory Pathologies

“…Greater exposure to cockroaches, rats, birds or dogs seems to be related with higher asthma prevalence and symptoms. 60,[67][68][69] However, exposure to cats does not seem to increase asthma symptoms, and a recent meta-analysis has even observed a protector effect for asthma from exposure to this animal. 70,71 Others For other diseases, the evidence is less consistent.…”

Environmental Effects on Fractional Exhaled Nitric Oxide in Allergic Children

“…Spanier et al found that cat and dog sensitizations were associated with increased FeNO [29]. Differently, Kovesi and Dales [32] found that dog ownership, but not cat ownership, was associated with changes in FeNO levels. …”