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2007-8-28 16:12:34 |
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Tuesday August 21, 2007 (Foodconsumer.org) -- Exhaust fumes have already been known to cause a number of health problems such as cancer, heart disease and stroke. Now a new study has found that they heighten the risk of asthma in children who are genetically susceptible to respiratory disease. The study published in the journal Thorax did not reveal if the exhaust fumes, which consist of a whole range of air pollutants, induce the genetic susceptibility to asthma in certain children. It found exposure to exhaust fumes have impact on the genes that control enzymes that are responsible for clearing of inhaled toxic chemicals, increasing risk of asthma and other respiratory diseases. The enzymes of concern include microsomal epoxide hydrolase (EPHX1) levels and genetic variations in gluathione S-transferase P1 (GSTP1). EPHX1 and GSTP1 help clear the body of toxins such as polyaromatic hydrocarbons from vehicle emissions. Among more than 3000 schoolchildren, researchers found that children with high EPHX1 activity were 1.5 times as likely to have asthma as those with low activity of the enzyme. If the children with high activity of EPHX1 carried a variation of the GSTP1 gene, they were four times as likely to have asthma compared to those with the variation. The genetic susceptibility seemed dependent upon proximity to road traffic pollution, according to Dr. Frank D. Gilliland, lead author of the study, from University of southern California School of Medicine and colleagues. Children with very high EPHX1 and living 75 meters of a main road were more than three times as likely to have asthma as those with relatively low EPHX1 levels. Children with one or two variations in the GSTP1 gene and living close to a major road were up to nine times as likely to have asthma compared to those who lives further away. The authors conclude that children with high EPHX1 activity and those who carry genetic variants of GSTP1 are at greater risk of having asthma. The risk was even greater when children live near a major road and are exposed to road traffic pollution. One early study by Fleming D. M. and Charlton J. R. from Birmingham Research Unit, Royal College of General Practitioners, Birmingham found that transportation workers were at higher risk of asthma and heart disease. The results were published in the August 2001 issue of The British Journal of General Practice. http://press.psprings.co.uk/thx/august/tx80127.pdf |
