辦公室員工之病態大樓症候群及氧化性傷害評估

Evaluation of Sick Building Syndrome and Urinary 8-Hydroxydeoxyguanosine in Office Workers

呂宗烟(Chung-Yen Lu)

指導教授 ： 宋鴻樟

共同指導教授 ： 馬一中(Yee-Chung Ma)

國立臺灣大學/公共衛生學院/環境衛生研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.02959

摘要

根據流行病學研究顯示，室內空氣污染物的暴露與病態大樓症候群﹙sick building syndrome, SBS﹚的產生有顯著相關，然而其致症候機轉仍無法釐清。為了解室內空氣污染物導致病態大樓症候群的機轉，本研究以流行病學方法，以隨機抽樣方式選取台北都會區內的8棟辦公大樓，面訪這些大樓內辦公室87間的417位內勤人員，調查台北都會區辦公大樓內之健康員工族群發生病態大樓症候群的盛行率，我們並配合各員工的辦公時間，分別於其所處的辦公室的室內和室外同時進行上午和下午各四小時的二階段空氣品質連續檢測，檢測的項目包括一氧化碳、二氧化碳、溫度、相對溼度和總揮發性有機物。本研究進一步做病例對照的尿液生化分析，測定員工之氧化傷害指標—DNA鍵結物8-烴基去氧鳥糞嘌呤核苷(8-hydroxydeoxyguanosine, 8-OHdG)和菸暴露代謝產物可丁寧（cotinine），以完備危險因子，並分別探討此症候群與室內空氣品質及氧化傷害情形三者間之相關性。本研究使用一般估計方程式﹙generalized estimating equations﹚克服〝資料須獨立性〞的限制，結果顯示辦公室內的二氧化碳濃度比室外濃度增加100 ppm，則員工發生喉嚨乾燥、疲倦、注意無法集中和昏眩的勝算比為1.05-1.13倍；室內增加100 ppb的總揮發性有機物，員工發生眼睛乾燥、眼睛刺激、鼻塞、打噴嚏、喉嚨乾燥、呼吸困難、皮膚乾燥、疲倦、注意無法集中、易怒和昏眩的勝算比為1.00-1.06倍。研究中分別以員工尿液中的8-烴基去氧鳥糞嘌呤核苷和可丁寧做為氧化傷害和菸暴露的評估指標，結果顯示8-烴基去氧鳥糞嘌呤核苷和可丁寧在未曾抽菸、戒菸和目前抽菸員工的分佈情形分別為5.08、5.93、10.9 µg/g creatinine和2.39、4.21、12.9 µg/g creatinine，菸的暴露明顯導致氧化傷害情形發生。研究進一步排除抽菸者資料後，分析室內空氣污染物與氧化傷害情形間之相關性，辦公室內和室外的二氧化碳濃度差值增加與員工產生較高濃度的8-烴基去氧鳥糞嘌呤核苷呈現劑量反應效應，顯示辦公室內換氣不良會導致員工氧化傷害情形增加。本研究亦發現員工尿液中8-烴基去氧鳥糞嘌呤核苷每增高1 µg/g creatinine，員工發生鼻塞、眼睛乾燥、喉嚨乾燥、昏眩、鼻子癢和打噴嚏的粗勝算比為1.09-1.52倍。員工的氧化傷害情形是否可作為病態大樓症候群的預測指標，值得進一步做研究。

關鍵字

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

並列摘要

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.

並列關鍵字

sick building syndrome ； oxidative stress ； 8-hydroxydeoxyguanosine ； high-rise building office ； carbon dioxide ； volatile organic compounds

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