Passive Smoking Linked to Loss of Genetic Protection Against Respiratory Illness

From Reuters Health Information

NEW YORK (Reuters Health) May 12 - Investigators at the University of Southern California in Los Angeles report evidence that second-hand exposure to tobacco smoke negates the protection against respiratory illness afforded by the glutathione S-transferase P1 (GSTP1) variants.

The study, by Dr. Frank D. Gilliland and colleagues, involved 1132 Hispanic and non-Hispanic fourth-grade children in the Children's Health Study and is published in the May issue of Pediatrics.

The investigators assessed tobacco smoke exposure, respiratory-related school absences and status of four GSTP1 single-nucleotide polymorphisms, which account for 93% of the variation across the locus.

Three of the four SNPs were associated with a decreased risk of respiratory illness. However, "the protective effect of GSTP1 variants was lost among individuals exposed to in utero and secondhand tobacco smoke," Dr. Gilliland and colleagues report.

"The paradigm of loss of genetic protection among those exposed to tobacco smoke has clinical and public health implications that warrant broader consideration in research and practice," the team concludes.

Pediatrics 2009;123:1344-1351.