Indoor Allergen Exposure and Its Association to Upper Respiratory Infections and Pulmonary Outcomes among Children with Asthma

Background Certain environmental allergen exposures are more common in disadvantaged communities and may contribute to differences in susceptibility to upper respiratory infections (URI). Objectives To examine associations between indoor allergens and: 1) URI; 2) URI + cold symptoms; 3) URI + cold symptoms + pulmonary eosinophilic inflammation (FENO≥20 ppb); and 4) URI + cold symptoms + reduced lung function (percent predicted FEV1<80%). Methods We used data from the Environmental Control as Add-on Therapy for Childhood Asthma study. Allergen concentrations were measured in air (mouse) and settled dust (mouse, cockroach, dog, and cat). URI was determined by testing nasal mucus for upper respiratory viruses. We evaluated associations between allergen concentrations and URI-associated outcomes accounting for age, sex, study month, season, health insurance, and household size. Results 90 participants (92% Black, 92% public insurance) with 192 observations were included; 52 (27%) of observations were positive for URI. A doubling in cockroach allergen concentration increased the odds of a URI with cold symptoms by 18% (odds ratios (OR) =1.18, 95% CI, 0.99-1.40), the odds of a URI + cold symptoms + pulmonary eosinophilic inflammation by 31% (OR=1.31, 95% CI, 1.10-1.57), and the odds of a URI + cold symptoms + reduced lung function by 45% (OR = 1.45, 95% CI, 1.13-1.85). Mouse allergen concentrations were positively associated with all outcomes. Associations were suggestively stronger among children sensitized to pest allergens. Conclusions Cockroach and mouse, but not dog or cat, allergen exposure may predispose children with asthma to URIs with colds and lower respiratory outcomes.