Children with high levels of EPHX1 and variations in GSTP1 genes had a fourfold increased risk.
Children who carry variations in specific genes that metabolize vehicle emissions are more susceptible to developing asthma, particularly if they live near major roadways, suggest scientists at the University of Southern California (USC).
The research drew upon data from the Children’s Health Study, a longitudinal survey of respiratory health among school-age children in 12 Southern California communities. They compared associations between numbers of genetic variants and exposure to toxins among more than 3,000 participants.
The USC team found that children with high levels of microsomal epoxide hydrolase (EPHX1), an enzyme that metabolizes polyaromatic hydrocarbons in vehicle emissions, were 1.5 times as likely to have asthma as those with low EPHX1. Children with increased EPHX1 who also carried certain variations in glutathione S-transferase P1 (GSTP1) genes were four times more likely to have asthma.
Among children who lived within 75 meters of a major road, those with raised EPHX1 activity were three times more likely to have asthma. Those who carried both variations in EPHX1 and GSTP1 and lived within 75 meters of a major road were at the highest asthma risk. The results were consistent for current, early, and late onset asthma.
The study will appear in Thorax and is now available online.
