Traffic Fumes Increase Asthma Risk For Children Who Are Genetically Susceptible

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Main Category: Respiratory / Asthma
Also Included In: Pediatrics / Children's Health;  Genetics
Article Date: 24 Aug 2007 - 4:00 PST

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Children who are genetically susceptible to respiratory diseases have a higher risk of asthma when exposed to exhaust fumes, according to an article published in Thorax (British Medical Journal). The article explains that gene variations that control enzymes that clear damaging chemicals we breathe in have been associated with the development of respiratory diseases, including asthma.

In this study, the scientists looked at microsomal epoxide hydrolase (EPHX1) levels and genetic variations in gluathione S-transferase P1 (GSTP1) in over 3,000 children who suffered from asthma. EPHX1 and GSTP1 are actively involved in ridding the body of toxins, including vehicle emissions (polyaromatic hydrocarbons).

They found that children with very active EPHX1 are 1.5 times as likely to suffer from asthma, compared to kids with low EPHX1 activity. Children with high EPHX1 levels who also had a GSTP1 gene variation were four times as likely to suffer from asthma, said the scientists.

How close the children were to road traffic seems to be a major factor in triggering genetic susceptibility. A child with a very active EPHX1 who lives within 75 meters of a busy road is over three times as likely to have asthma, compared to a child with relatively low EPHX1 levels. A child with one or two GSTP1 gene variations who lives near a busy road is up to nines times as likely to have asthma, compared to a child who does not live near a busy road, said the researchers.

The researchers found that these figures did not change whether a child's asthma was current, had started early, or later on in life.

They concluded that a child with high EPHX1 activity who carries GSTP1 genetic variants is more likely to develop asthma. However, proximity to a main road - or traffic pollution - increases that risk significantly more.

"Microsomal epoxide hydrolase, glutathione S-transferase P1, traffic and childhood asthma"
Online First Thorax 2007; doi: 10.1136/thx.2007.080127
Muhammad T Salam, Pi-Chu Lin, Edward L Avol, W. James Gauderman and Frank D Gilliland
Click here to view abstract online

Written by: Christian Nordqvist
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