| Summary: | 碩士 === 高雄醫學大學 === 公共衛生學研究所碩士班 === 94 === 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.
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