Swedish researchers have found that exposure to traffic-related air pollution during infancy was associated with decreases in lung function at age eight.
"Earlier studies have shown that children are highly susceptible to the adverse effects of air pollution and suggest that exposure early in life may be particularly harmful," said researcher Goran Pershagen, professor at the Karolinska Institutet Institute of Environmental Medicine in Stockholm, Sweden.
"In our prospective birth cohort study in a large population of Swedish children, exposure to traffic-related air pollution during infancy was associated with decreases in lung function at age eight, with stronger effects indicated in boys, children with asthma and particularly in children sensitised to allergens," Pershagen said.
The study included more than 1,900 children who were followed from birth through age eight with repeated questionnaires, spirometry and immunoglobulin E measurements.
Outdoor concentrations of particulate matter from road traffic were estimated for residential, daycare and school addresses using dispersion modeling, a mathematical simulation of how air pollutants disperse in the atmosphere.
A 5th to 95th percentile difference in time-weighted exposure to outdoor concentrations of particulate matter from road traffic during the first year of life was associated with a reduced forced expiratory volume in one second.
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This negative association was particularly pronounced in children who were sensitized to common inhalant and/or food allergens and also seemed stronger among boys and among children with asthma.
Exposure to traffic-related air pollution after the first year of life appeared to have less impact on subsequent lung function.
The findings were published in the American Journal of Respiratory and Critical Care Medicine.