Air pollution and development of asthma, allergy and infections in a birth cohort

TLDR

Few studies have examined the link between traffic‑related air pollution and respiratory disease in young children. This study evaluated the development of asthma, allergy, and respiratory infections over the first four years of life in a birth cohort of about 4,000 children. Researchers estimated traffic‑related pollutant concentrations at each child’s birth home using a land‑use regression model, linked these exposures to questionnaire data on asthma, bronchitis, influenza, eczema, wheeze, cough, infections, and rash via logistic regression, and measured total and specific IgE in a subgroup of 713 children. Elevated traffic‑related pollution was associated with higher odds of wheeze, doctor‑diagnosed asthma, ear/nose/throat infections, flu/serious colds, and specific food‑allergen sensitisation, while no consistent associations were observed for other outcomes.

Abstract

Few studies have addressed associations between traffic-related air pollution and respiratory disease in young children. The present authors assessed the development of asthmatic/allergic symptoms and respiratory infections during the first 4 yrs of life in a birth cohort study (n = approximately 4,000). Outdoor concentrations of traffic-related air pollutants (nitrogen dioxide PM(2.5), particles with a 50% cut-off aerodynamic diameter of 2.5 mum and soot) were assigned to birthplace home addresses with a land-use regression model. They were linked by logistic regression to questionnaire data on doctor-diagnosed asthma, bronchitis, influenza and eczema and to self-reported wheeze, dry night-time cough, ear/nose/throat infections and skin rash. Total and specific immunoglobulin (Ig)E to common allergens were measured in a subgroup (n = 713). Adjusted odds ratios (95% confidence intervals) per interquartile pollution range were elevated for wheeze (1.2 (1.0-1.4) for soot), doctor-diagnosed asthma (1.3 (1.0-1.7)), ear/nose/throat infections (1.2 (1.0-1.3)) and flu/serious colds (1.2 (1.0-1.4)). No consistent associations were observed for other end-points. Positive associations between air pollution and specific sensitisation to common food allergens (1.6 (1.2-2.2) for soot), but not total IgE, were found in the subgroup with IgE measurements. Traffic-related pollution was associated with respiratory infections and some measures of asthma and allergy during the first 4 yrs of life.