Evaluation of Sick Building Syndrome and Urinary 8-Hydroxydeoxyguanosine in Office Workers
Date Issued
2007
Date
2007
Author(s)
Lu, Chung-Yen
DOI
en-US
Abstract
This study investigated whether sick building syndrome (SBS) complaints and indoor air quality for office workers are associated with oxidative stress indicated by urinary 8-hydroxydeoxyguanosine (8-OHdG). With informed consent, 417 employees in 87 offices rooms of 8 high rise buildings completed the self-reported questionnaire for the information on building related symptoms experienced at work during the past month. For the association with the symptoms, carbon monoxide (CO), carbon dioxide (CO2), temperature, humidity and total volatile organic compounds (TVOCs) for each office of respondents were simultaneously measured for eight office hours using portable monitors. Time-averaged workday difference between the indoor and the outdoor CO2 concentrations (dCO2) was calculated as a surrogate measure of ventilation rate for each office unit. The prevalence rates of SBS were 22.5% for eye syndrome, 15.3% for upper respiratory and 6.5% for lower respiratory, 1.9% for skin dryness and 25.4% for non-specific syndromes. Tiredness (20.9%), difficulty in concentrating (14.6%), eye dryness (18.7%) were common complaints. The generalized estimating equations multivariate logistic regression analyses showed that adjusted odds ratios (OR) for per 100 ppm increases in dCO2 were statistically significant for dry throat (1.05), tiredness (1.09), difficulty in concentrating (1.08) and dizziness (1.13). The adjusted odds ratios for per 100 ppb increases in TVOCs were statistically significant for eye dryness and irritation, stuffy nose, sneezing, dry throat, difficulty in breathing, skin dryness, tiredness, difficulty in concentrating, angry easily and dizziness (OR = 1.00-1.06). The association between some SBS symptoms and the exposure to CO2 and total VOCs are small but may be independently significant.
Urinary 8-OHdG was determined for 311 never smokers, 33 former smokers and 45 current smokers of study participants. The average urinary cotinine concentrations were 2.39, 4.21 and 12.9 µg/g creatinine in never smokers, former smokers and current smokers, respectively, with the corresponding average 8-OHdG concentrations of 5.08, 5.93 and 10.9 µg/g creatinine. The urinary 8-OHdG concentrations were significantly associated with urinary cotinine concentrations (r = 0.62). Using the overall median 8-OHdG level of 4.99 µg/g creatinine as the cut-off value, the multivariate logistic regression analysis showed that current smokers had an odds ratio (OR) of 5.48 (95% confidence interval (CI) = 1.41-21.4) to have elevated 8-OHdG concentration. This analysis also showed that employees in the third and the highest quartile levels of urinary cotinine had the odds ratios of 5.18 (95% CI=2.74-9.76) and 8.22 (95% CI=3.71-18.2), respectively, to have high 8-OHdG level. Tobacco smoke exposure was the major contribution for office employees to have elevated urinary 8-OHdG levels.
We further measured the urinary 8-OHdG levels to determine the interaction between exposures to CO2 and TVOCs. Means of urinary 8-OHdG contents were calculated by tertiles of dCO2 (＜390 ppm, 390-680 ppm and ＞680 ppm) and tertiles of TVOCs (＜114 ppb, 114-360 ppb and ＞360 ppb). The average urinary 8-OHdG levels among non-smokers of study participants increased from 3.10µg/g creatinine, for those at the lowest tertile levels of both dCO2 and TVOCs, to 6.27 µg/g creatinine, for those at the highest tertile levels. The generalized estimating equations of multivariate logistic regression analyses showed that the risk of having the urinary 8-OHdG level of greater than the median, 4.53 µg/g creatinine, for participants increased significantly at the highest tertile dCO2 level of > 680 ppm (odds ratio (OR) = 3.37, 95% confidence interval (CI) = 1.29-8.80). The effect was significant at the middle tertile TVOCs level of 114-360 ppb (OR = 2.62, 95% CI = 1.01-6.78), but not at the highest tertile. Inadequate ventilation in office increases the risk of building-related oxidative stress in non-smoking employees.
The mean urinary 8-OHdG level in participants with SBS symptoms was also significantly higher than those without such complaints (6.16 vs. 5.45 µg/g creatinine, p = 0.047). The mean 8-OHdG increased as the number of SBS symptoms increased. The generalized estimating equations multivariate logistic regression analyses showed that the adjusted odds ratios (OR) in relation to per µg/g creatinine increase in 8-OHdG were statistically significant for sneezing (1.52), nose itching (1.24), dizziness (1.23), dry throat (1.21), eye dryness (1.11) and stuffy nose (1.09). This study indicates that the 8-OHdG level was significantly associated with SBS complaints after controlling for air pollution and smoking. Whether the 8-OHdG can be used as an effective predictor for SBS symptoms deserves further study.
Subjects
病態大樓症候群
二氧化碳
總揮發性有機物
8-烴基去氧鳥糞嘌呤核苷
可丁寧
一般估計方程式
sick building syndrome
oxidative stress
8-hydroxydeoxyguanosine
high-rise building office
carbon dioxide
volatile organic compounds
Type
thesis
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