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

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 (n5,4,000).Outdoor concentrations of traffic-related air pollutants (nitrogen dioxide PM 2.5 , particles with a 50% cut-off aerodynamic diameter of 2.5 mm 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 selfreported 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 (n5713).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.

Repeated hospital encounters for asthma in children and exposure to traffic-related air pollution near the home

“…Asthma diagnosis can be made using objective methods, such as spirometry, at school ages. Nevertheless, given other evidence, 12,40 it is conceivable that air pollutants also enhanced the propensity toward lower respiratory tract illness-related wheeze in the present population.…”

“…These findings suggest that early-life exposures to traffic pollutants may affect asthma severity and development. This view is supported by studies [12][13][14][15][16][17][18] of preschool children that have found increased risk of incident asthma or wheeze or cough without a cold from long-term exposures to local trafficrelated air pollutants using GIS-based methods. A recent study 35 showed acute increases in wheeze occurrence with elevations in daily regional NO 2 and NO x levels in infants and children followed up during their first 3 years of life.…”

“…9 High home or school traffic density has been associated with prevalence of diagnosed asthma in epidemiologic studies. 10,11 Cohort studies [12][13][14][15][16][17][18] have shown associations between asthma incidence or early wheeze or cough without a cold and traffic-related air pollution near the homes of preschool children using geographic information system (GIS)-based exposure models.…”

On exposure and response relationships for health effects associated with exposure to vehicular traffic

“…Hypertension and road traffic noise (Bluhm et al, 2007). Impaired respiratory health (Oosterlee et al, 1996;Schikowski et al, 2005;Bayer-Oglesby et al, 2006;Sunyer et al, 2006;Brauer et al, 2007;Morgenstern et al, 2007). Diminished lung function (Sekine et al, 2004;Hong et al, 2005;Kan et al, 2007;McCreanor et al, 2007).…”

“…Asthma prevalence (Arif and Shah, 2007;Brauer et al, 2007;Carbajal-Arroyo et al, 2007). Children's lung development (Gauderman et al, 2007) Respiratory symptoms (Gordian et al, 2006).…”