Exposure to Traffic-Related Particles and Endotoxin During Infancy Is Associated With Wheezing At Age Three.

Murine models demonstrate a synergistic production of reactive oxygen species upon co-exposure to diesel exhaust particles and endotoxin. It was hypothesised that co-exposure to traffic-related particles and endotoxin would have an additive effect on persistent wheezing during early childhood. Persistent wheezing at age 36 months was assessed in the Cincinnati Childhood Allergy and Air Pollution Study, a high-risk birth cohort. A time-weighted average exposure to traffic-related particles was determined by applying a land-use regression model to the homes, daycares, and other locations where children spent time from birth through age 36 months. Indoor levels of endotoxin were measured from dust samples collected prior to age 12 months. The relationship between dichotomised (< / 75th percentile) traffic-related particle and endotoxin exposure and persistent wheezing, controlling for potential covariates, was examined. Am J Respir Crit Care Med. 2009;180(11):1068-75. Epub 2009 Sep 10.