A Meta-Analysis of Studies on Air Pollution in Urban Areas Along Highways and Lung Disease Including Asthma Among Children

Background –

Asthma is a serious illness that affects people across all spectrums. According to the CDC, more than 17 million people are affected by asthma in the United States, of which a third of those are children. A factor that increases children's vulnerability to air borne pollution is that their airways are narrower than those of adults.

Method –

Articles from 1999-2009, related to highway air pollution, were retrieved from Highwire, Pubmed, and Medline search engines. Confidence intervals relating to individual air contaminants (PM2.5, CO, O3, NO2) were obtained. Results were stratified on the following inclusion criteria – a) air pollution, b) asthma, c) children and d) case control studies. Meta-analysis was conducted and random effect models were generated.

Results –

As per the meta-analysis – (OR – 1.041, CI (1.027- 1.056), Z – 143.627, P – 0.000) indicates that air pollutants are a triggering factor for asthma exacerbation and allergies. Exposure to particulate matter (PM2.5, PM10) and carbon monoxide are associated with decreased pulmonary functions and hospital admission among asthmatic children.

Conclusion –

A meta-analysis of 20 case control studies suggests that there is a considerable association between proximity to highways and results in adverse respiratory health effects in children. High ambient levels of PM 10, PM2.5, NO2 and O3 are associated with increased risk of childhood asthma symptoms. Therefore we can infer that highway air pollutants have a major effect on the development of asthma in young children.