ENOS gene polymorphisms modify the association of PM₁₀ with oxidative stress

Previous studies have suggested that air pollution increases various health outcomes through oxidative stress and oxidative stress-related genes modify the relationship between air pollution and health outcomes. Therefore, we evaluated the effect of PM₁₀ on the levels of malondialdehyde (MDA), oxidative stress biomarker, and the effect modification by genetic polymorphisms of eNOS, oxidative stress-related gene, in the 560 Korean elderly. We obtained urine samples repeatedly from participants during five medical examinations between 2008 and 2010 and all ambient air pollutant concentration data from the Korea National Institute of Environmental Research air quality monitoring system. We measured urinary levels of MDA to assess oxidative stress and genotyped eNOS (rs1799983, rs2853796, and rs7830). Mixed-effect model was used to estimate the effect of PM₁₀ on the level of oxidative stress biomarker and their modification by genotypes. PM₁₀ showed apparent positive effect on MDA level after adjusting for age, sex, BMI, cotinine level, temperature, dew point, levels of SO₂, O₃, NO₂, and CO, and season (p=0.0133). Moreover, the association of PM₁₀ with MDA was found only in participants with eNOS GG genotype for rs1799983 (p=0.0107), TT genotype for rs2853796 (p=0.0289), or GT genotype for rs7830 (p=0.0158) and in participants with a set of risky haplotypes (GTT, GTG, GGT, and TGT) (p=0.0093). Our results suggest that PM₁₀ affect oxidative stress in the elderly and eNOS genotype affect the oxidative stress level in regard of exposure to PM₁₀.