Lung function growth in children with long-term exposure to air pollutants in Mexico City

Rationale: Although short-term exposure to air pollution has been associated with acute, reversible lung function decrements, the impact of long-term exposure has not been well established. Objectives: To evaluate the association between long-term exposure to ozone (03), particulate matter less than 10 mu m in diameter (PM10), and nitrogen dioxide (NO2) and lung function growth in Mexico City schoolchildren. Methods: A dynamic cohort of 3,170 children aged 8 years at baseline was followed from April 23, 1996, through May 19, 1999. The children attended 39 randomly selected elementary schools located near 10 air quality monitoring stations and were visited every 6 months. Statistical analyses were performed using general linear mixed models. Measurements and Main Results: After adjusting for acute exposure and other potential confounding factors, deficits in FVC and FEV1 growth over the 3-year follow-up period were significantly associated with exposure to 03, PM10, and NO2. In multipollutant models, an interquartile range (lQR) increase in mean O-3 concentration (lQR, 11.3 ppb) was associated with an annual deficit in FEV1 of 12 ml in girls and 4ml in boys, an lQR range (lQR, 36.4 mu g/m(3)) increase in PM10 with an annual deficit in FEV1 of 11 ml in girls 15 ml in boys, and an IQR range (IQR, 12.0 ppb) increase in NO2 with an annual deficit in FEV1 of 30 ml in girls and 25 ml in boys. Conclusions: We conclude that long-term exposure to 03, PM10, and NO2 is associated with a deficit in FVC and FEV1 growth among schoolchildren living in Mexico City.