Ozone exposure, antioxidant genes, and lung function in an elderly cohort: VA normative aging study

Ozone (O3) exposure is known to cause oxidative stress. This study investigated the acute effects of O(3) on lung function in the elderly, a suspected risk group. It then investigated whether genetic polymorphisms of antioxidant genes (heme oxygenase-1 (HMOX1) and glutathione S-transferase pi (GSTP1)) modified these associations.

1100 elderly men from the Normative Aging Study were examined whose lung function (forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)) was measured every 3 years from 1995 to 2005. The study genotyped the GSTP1 Ile105Val and Ala114Val polymorphisms and the (GT)n repeat polymorphism in the HMOX1 promoter, classifying repeats as short (n<25) or long (n> or =25). Ambient O(3) was measured continuously at locations in the Greater Boston area. Mixed linear models were used, adjusting for known confounders.

A 15 ppb increase in O(3) during the previous 48 h was associated with a 1.25% decrease in FEV(1) (95% CI: -1.96% to -0.54%). This estimated effect was worsened with either the presence of a long (GT)n repeat in HMOX1 (-1.38%, 95% CI: -2.11% to -0.65%) or the presence of an allele coding for Val105 in GSTP1 (-1.69%, 95% CI: -2.63% to -0.75%). A stronger estimated effect of O(3) on FEV(1) was found in subjects carrying both the GSTP1 105Val variant and the HMOX1 long (GT)n repeat (-1.94%, 95% CI: -2.89% to -0.98%). Similar associations were also found between FVC and O(3) exposure.

Our results suggest that O(3) has an acute effect on lung function in the elderly, and the effects may be modified by the presence of specific polymorphisms in antioxidant genes.