Oxidative DNA damage estimated by urinary 8 -hydroxydeoxyguanosine and indoor air pollution among non-smoking office employees

Abstract This study investigated whether urinary 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative stress, was associated with indoor air quality for non-smokers in high-rise building offices. With informed consents, urine samples from 344 non-smoking employees in 86 offices were collected to determine 8-OHdG concentrations. The concentrations of carbon dioxide (CO 2 ) and total volatile organic compounds (TVOCs) in each office and outside of the building were simultaneously measured for eight office hours. The average workday difference between indoor and outdoor CO 2 concentrations (dCO 2 ) was used as a surrogate measure of the ventilation efficiency for each office unit. The CO 2 levels in the offices ranged 467–2810 ppm with a mean of 1170 ppm, or 2.7 times higher than that in the outside air. The average urinary 8-OHdG levels among employees increased from 3.10 μg/g creatinine, for those at the lowest tertile levels of both dCO 2 and TVOCs, to 6.27 μg/g creatinine, for those at the highest tertile levels. Multivariate logistic regression analysis showed that the risk of having the urinary 8-OHdG level of greater than the median, 4.53 μg/g creatinine, for participants was increased significantly at the highest tertile dCO 2 level of >680 ppm (odds ratio (OR)=3.37, 95% confidence interval (CI)=1.20–9.46). The effect was significant at the middle tertile TVOCs level of 114–360 ppb (OR=2.62, 95% CI=1.43–4.79), but not at the highest tertile. Inadequate ventilation in office increases the risk of building-related oxidative stress in non-smoking employees.