Fine Particulate Matter Correlated with Wheezing in Infants
Physicians in Santiago, Chile have reported that increased daily concentrations of PM2.5 are tied to an increased risk of wheezing bronchitis in babies.
Doctors followed a group of 500 four-month old healthy infants on a monthly basis until they reached their first birthdays. They collected data on fine particulate matter, sulfur dioxide, and nitrogen dioxide from the government air monitoring network. Mobile sources, in particular diesel engines, are the major source of fine particle air pollution in Santiago and the study was conducted in an area with high-traffic density.
After adjusting for sex, socioeconomic level, family history of asthma, temperature and number of siblings, they found that a daily increase of 10 µg/m3 PM2.5 was related to a 5 percent increase in the risk of wheezing bronchitis the next day. The increase in wheezing was evident up to nine days after the exposures occurred. A family history of asthma also increased the risk. No association was detected with the other pollutants.
The results of this study are consistent with studies of environmental tobacco smoke exposure and lower respiratory health in young children. Multiple episodes of wheezing in the first year of life are related to an increase of asthma in older children. The researchers concluded that “air pollution in the form of fine particulates, mostly from vehicular exhaust, may adversely affect infants’ respiratory health with potential for chronic effects later in life.”
Pino P, Walter T, Oyarzun M, Villegas R, Romieu I. Fine particulate matter and wheezing illnesses in the first year of life. Epidemiology 2004; 15:702-708.
The National Library of Medicine [www.ncbi.nlm.nih.gov] offers the abstract online.
