The Association of Long-Term Traffic-Related Air Pollution Exposure with Asthma and Poor Lung Function in Middle Age

Current evidence concerning the impact of exposure to traffic-related air pollution (TRAP)on adult respiratory morbidity mainly comes from cross-sectional studies. We sought to establish morerobust measures of this association and potential gene–environment interactions using longitudinal datafrom an established cohort study.Associations between measures of TRAP (nitrogen dioxide (NO2) and distance to major roads) andwheeze, asthma prevalence and lung function were investigated in participants of the TasmanianLongitudinal Health Study at 45- and 50-year follow-ups. Generalised estimating equations were used toquantify associations and the potential modifying effect of glutathione S-transferase gene variants.Living GSTT1 null and GSTP1 val/val or ile/valgenotypes. Over the 5-year period, higher NO2 exposures were associated with increased current asthmaprevalence. Higher NO2 exposure was associated with lower forced vital capacity for carriers of the GSTT1null genotype.TRAP exposures were associated with increased risk of asthma, wheeze and lower lung function inmiddle-aged adults. The interaction with the GSTT1 genotype suggests that deficient antioxidantmechanisms may play a role in these adverse health effects