Residential outdoor air pollution and lung function in schoolchildren.
BACKGROUND
Long-term exposure to outdoor air pollution has typically been estimated on the aggregate level, and more individual measures of exposure are needed. We investigated the associations with lung function of residential outdoor air pollution in early life, total lifetime, and days before lung function test.


METHODS
In 2001-2002, spirometry was performed in 2307 9- and 10-year-old children who had lived in Oslo, Norway, since birth. Outdoor air pollution exposure for each child was assessed by the EPISODE dispersion model, calculating hourly concentrations of nitrogen dioxide (NO2), particulate matter (PM) with aerodynamic diameter less than 10 microm (PM10) and 2.5 microm (PM2.5). We applied linear regression analysis stratified by sex.


RESULTS
Early and lifetime exposures to outdoor air pollution were associated with reduced peak expiratory flow and reduced forced expiratory flow at 25% and 50% of forced vital capacity, especially in girls. One interquartile increase of lifetime exposure to NO2, PM10, and PM2.5 was associated with change in adjusted peak respiratory flow of, respectively, -79 mL/s (95% confidence interval = -128 to -31), -66 mL/s (-110 to -23), and -58 mL/s (-94 to -21). We also found short-term effects of NO2 that became stronger with increasing time lags, but no short-term effects of PM. When we included short- and long-term NO2 exposures simultaneously, only the long-term effect remained. We found no effect on forced volumes. Adjusting for a contextual socioeconomic factor diminished the associations.


CONCLUSIONS
Short- and long-term residential exposures to traffic-related pollutants in Oslo were associated with reduced peak expiratory flow and forced expiratory flow at 25% and 50% in 9- to 10-year-old children, especially in girls, with weaker associations after adjusting for a contextual socioeconomic factor.
Oftedal
Bente
B
Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway. bente.oftedal@fhi.no
Brunekreef
Bert
B
Nystad
Wenche
W
Madsen
Christian
C
Walker
Sam-Erik
SE
Nafstad
Per
P
D000393:Air Pollutants / Q000032:analysis* / Q000633:toxicity*; D002648:Child; D004784:Environmental Monitoring / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000503:physiopathology*; D008297:Male; D009585:Nitrogen Dioxide / Q000032:analysis* / Q000633:toxicity; D009664:Norway / Q000453:epidemiology; D012111:Residence Characteristics; D012119:Respiration; D012737:Sex Factors; D013147:Spirometry; D001335:Vehicle Emissions
D000393:Air Pollutants; D001335:Vehicle Emissions; D009585:Nitrogen Dioxide