Exposure to volatile organic compounds and loss of pulmonary function in the elderly

Volatile organic compounds (VOCs) are reported to cause adverse effects on pulmonary function in occupationally exposed workers. However, evidence is lacking on the effect in the general population. We hypothesised that VOCs impair pulmonary function through enhancing oxidative stress, especially in the elderly population. A longitudinal panel study of 154 elderly people was performed in South Korea. Repeated spirometric tests were performed up to eight times on different days for each subject. We also measured urinary concentrations of metabolites of the VOC and markers of oxidative stress (malondialdehyde and 8-oxo-2'-deoxyguanosine) on the same day of spirometric tests. A mixed linear regression model was used to evaluate the association among the VOC metabolites, oxidative stress markers and spirometric tests. We found that the urinary levels of hippuric acid and methylhippuric acid, which are metabolites of toluene and xylene, respectively, were significantly associated with reduction of forced expiratory volume in 1 s (FEV₁), FEV₁/forced vital capacity (FVC), and forced expiratory flow at 25-75% of FVC. We also found significant associations between the metabolites of VOCs and the markers of oxidative stress. In addition, the oxidative stress markers were associated with pulmonary function parameters. This study suggests that exposure to toluene and xylene exert a harmful effect on pulmonary function by exacerbating oxidative stress in elderly people.