Variations in Peak Expiratory Flow Measurements Associated to Air Pollution and Allergic Sensitization in Children in São Paulo, Brazil

Abstract

ISEE-0800 Background and Objective: The health effects of air pollution range from lung function decrements to mortality. In the last 20 years, there has been an increase in the incidence of allergic respiratory diseases worldwide. Even though genetic factors play an important role, air pollution has been discussed as one of the factors responsible for this increase. The objective of this study was to investigate the effects of air pollution on peak expiratory flow of children who were sensitized and children who were not. Methods: Ninety-six children (9 to 11 years old) were followed from April to July, 2004 with daily measurements of peak expiratory flow. Blood samples were collected for IgE and total blood count. Skin prick test was done using common allergens: mites (Dermatophagoides pteronyssinus, Dermatophagoides farinae e Blomia tropicalis), dog (Canis familiaris), cat (Felis domesticus), cockroach (Periplaneta americana) and fungus (Aspergillus fumigatus, Alternaria alternata, Cladosporium herbarium, Chaetomium globosum, Mucor mucedo, Pullularia pullulans, Penicillium notatum). Daily hourly concentrations of all criteria pollutants, temperature and relative humidity were available for the entire period. Analysis was performed with the generalized estimated equations (GEE). Results: A decrease in peak flow measurements was found to be associated mainly with PM10, NO2 and O3, considering different time lags (hours, previous day, moving average). The effects of the pollutants were not different between children with or without allergic sensitization. Conclusion: Even though air pollution had a small effect on peak flow measurements (less than 1% decrease), children are exposed to this air on a daily basis and this exposure can lead to a chronic inflammatory process that might impair their lung function in adulthood. This study does not support previous findings of a different effect of air pollution on respiratory function of children with allergic sensitization.