台灣地區飲用水中消毒副產物與生殖危害相關研究

Association between Disinfection By-Products of Drinking Water and Adverse Birth Outcomes in Taiwan

蕭志屏(Zhi-Ping Shiao)

指導教授 ： 楊俊毓

高雄醫學大學/健康科學院/公共衛生學研究所/碩士(2006年)

摘要

背景：淨水場在飲用水的處理過程中，主要以加氯消毒的方式來抑制水中微生物孳生與水媒疾病的傳播，但根據以往研究顯示氯劑會與水中有機物質反應產生對人體有害的消毒副產物，甚至有研究證實消毒副產物與膀胱、結腸直腸、胰臟、腎臟等癌症的發生有關；近來，有動物實驗指出消毒副產物可能為一致畸胎物質，因此最近研究都將重點放在消毒副產物與生殖危害之間相關性的探討。

研究目的：觀察台灣地區民國89年至91年期間，懷孕期間的總三鹵甲烷平均暴露濃度是否會對新生兒的出生體重、妊娠週數產生影響，並進一步評估總三鹵甲烷與生殖危害（低出生體重兒、足月低出生體重兒、早產兒、子宮內生長遲緩兒）之間的相關性。

材料與方法：本研究資料來源為合併內政部之出生資料檔與環境保護署飲用水水質標準中較難檢驗項目抽驗計畫之總三鹵甲烷檢測數值，並利用橫斷型研究方法觀察民國89年1月至91年12月期間出生於台灣地區之90848位單胞胎嬰兒，利用線性迴歸分析總三鹵甲烷與出生體重、妊娠週數之相關性，再以多變項對數迴歸分析總三鹵甲烷不同濃度與四種生殖危害，求其發生之危險對比值。並以出生登記資料收錄之產婦及新生兒的個別資料，來調整其中可能的干擾因子。

結果：在總三鹵甲烷濃度與新生兒出生體重方面，當濃度每上升100 µg/L時，則新生兒出生體重則降低76.6公克重，而高濃度（＞13.11µg/L）與低濃度（≦4.93µg/L）相比，則新生兒出生體重降低13.9公克重；在總三鹵甲烷濃度與新生兒妊娠週數方面，當濃度每上升100 µg/L時，則新生兒妊娠週數則減少0.54週，而高濃度與低濃度相比，則新生兒妊娠週數減少0.1週；在本研究並沒有觀察到總三鹵甲烷濃度與低出生體重兒、足月低出生體重兒之間有相關性存在，也沒有證據顯示總三鹵甲烷濃度會造成子宮內生長遲緩兒相對危險性升高的趨勢，但在早產兒的部分，調整其他可能的干擾因素之後，可以看出暴露於較高的總三鹵甲烷濃度時，發生早產兒的相對危險性為1.08，而且隨著濃度的升高，其發生早產兒的相對危險性也有上升的趨勢，但並不明顯。

討論與結論：本研究結果顯示，產婦在懷孕期間的總三鹵甲烷暴露可能會導致新生兒出生體重降低、妊娠週數減少的情形產生；不過在總三鹵甲烷濃度與生殖危害方面，並未觀察到與之前國外相關研究有較一致的結果，不過，在早產兒方面，我們發現總三鹵甲烷與早產兒之間有微弱的正相關性，其餘在低出生體重兒、足月低出生體重兒、子宮內生長遲緩兒方面，並未觀察到與總三鹵甲烷之間有相關性存在。
整體而言，本研究與之前國外的研究比較之下，除了在生殖危害的定義不盡相同之外，消毒副產物濃度也明顯低於其他國家的檢測值，因此在本研究中不易看出與國外相關研究一致的結果。

關鍵字

消毒副產物 ； 生殖危害 ； 總三鹵甲烷 ； 低出生體重 ； 早產 ； 子宮內生長遲緩

並列摘要

Background：
Chlorination has been the major disinfectant process for domestic drinking water in killing waterborne organisms . However, chlorine reacts with organic materials in water and produces a number of disinfection by-products to effect human health. Disinfection by-products(DBPs) in drinking water have received considerable interest because of their possible association with bladder、colon、rectum、pancreas and kidney cancer. Recently, animals studies have indicated that some of these contaminants are teratogens. Therefore, epidemiological studies focus on that exposure to increased levels of DBPs may be associated with adverse reproductive outcomes.
Purpose：
The purpose of this study is to examine the effect of pregnancy average total trihalomethane(TTHM) exposure on infant birth weight、term low birth weight and small for gestational age(SGA) in term birth , as well as maternal gestational age、low birth weight and preterm delivery in all birth.
Material ＆ Methods：
We combined the birth registration data and annual monitoring total trihalomethane concentration data from 2000 to 2002.Cross-sectional analysis of 90848 singleton infants born to residents of Taiwan during 2000 to 2002.We use linear regression analysis to evaluate the effect of pregnancy average total trihalomethane(TTHM) exposure on infant birth weight in term birth and birth weight、maternal gestational age in all birth. We use logistic regression analysis to calculate the odds ratio of TTHM exposure on term low birth weight、SGA in term birth and low birth weight、preterm delivery in all birth.
Results：
After adjusting for gestational age and other covariates , we observed infant birth weight reductions of 76.6 g for each 100 μg/L increase in pregnancy average TTHM concentration. Compare to ≦4.93 μg/L, pregnancy average TTHM exposure over 13.11 μg/L was associated with a 13.9 g reduction in birth weight. After adjusting for other covariates , we observed maternal gestational age reductions of 0.54 week for each 100 μg/L increase in pregnancy average TTHM concentration. Compare to ≦4.93 μg/L, pregnancy average TTHM exposure over 13.11 μg/L was associated with a 0.1 week reduction in maternal gestational age. There was no evidence of an association between low birth weight、term low birth weight、SGA and increase TTHM levels, but there were slight increase in preterm delivery associate with TTHM concentrations.
Discussion ＆ Conclusions：
Maternal exposure to TTHM may be associated with infant birth weight and maternal gestational age reductions. However, our finding are not consistent with most previous studies, although we generally found small effect of TTHM on preterm delivery. Overall, summarizing the epidemiologic evidence for causal relationships between drinking water contaminants and adverse birth outcomes is difficult because of methodological differences across studies, and the levels of contaminants in drinking water also distinct lower than previous studies.

並列關鍵字

Disinfection by-products(DBPs) ； Adverse reproductive outcomes ； total trihalomethane(TTHM) ； Low birth weight(LBW) ； Preterm delivery ； Small for gestational age(SGA)

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