Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education, Ministry of Environmental Protection, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
Department of Epidemiology and Biostatistics, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
Sci Total Environ. 2017 May 15;586:313-318. doi: 10.1016/j.scitotenv.2017.01.224. Epub 2017 Feb 4.
Maternal exposure to drinking water disinfection by-products (DBPs) during pregnancy has been related to adverse birth outcomes. While experimental studies have shown that exposure to DBPs induce DNA hypomethylation, evidence from humans is limited. This study aimed to examine whether prenatal exposure to drinking water DBPs was associated with DNA methylation in cord blood. Maternal biomarkers of exposure to drinking water DBPs including blood trihalomethanes [THMs, including chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)] and urinary trichloroacetic acid (TCAA) were measured during late pregnancy. DNA methylation in Alu and long interspersed nucleotide element-1 (LINE-1) repetitive elements from cord blood samples (n=115) was measured by pyrosequencing. We used multivariable linear regression to estimate the associations of DNA methylation in cord blood with maternal blood THMs and urinary TCAA. We found no statistically significant association between urinary TCAA and DNA methylation. However, we found that blood TBM was associated with decreased Alu methylation (-0.39%; 95% CI: -0.83%, 0.05% for the highest versus lowest exposure group; p for trend=0.08) and decreased LINE-1 methylation (-1.27%; 95% CI: -2.91%, 0.36% for the highest versus lowest exposure group; p for trend=0.06). Our results suggest that prenatal exposure to drinking water TBM is associated with DNA hypomethylation in cord blood. However, further studies are needed to confirm our findings.
母体在怀孕期间暴露于饮用水消毒副产物（DBPs）与不良出生结局有关。虽然实验研究表明，暴露于 DBPs 会导致 DNA 低甲基化，但来自人类的证据有限。本研究旨在探讨产前暴露于饮用水 DBPs 是否与脐带血中的 DNA 甲基化有关。在妊娠晚期测量了母体暴露于饮用水 DBPs 的生物标志物，包括血液中的三卤甲烷（THMs，包括氯仿（TCM）、溴二氯甲烷（BDCM）、二溴氯甲烷（DBCM）和溴仿（TBM））和尿液中的三氯乙酸（TCAA）。通过焦磷酸测序测量了脐带血样本中 Alu 和长散布核元件-1（LINE-1）重复元件的 DNA 甲基化。我们使用多变量线性回归来估计脐带血中 DNA 甲基化与母体血液 THMs 和尿液 TCAA 之间的关联。我们发现尿液 TCAA 与 DNA 甲基化之间没有统计学上的显著关联。然而，我们发现血液 TBM 与 Alu 甲基化减少（-0.39%；95%置信区间：最高暴露组与最低暴露组相比为-0.83%，0.05%；趋势检验 p 值=0.08）和 LINE-1 甲基化减少（-1.27%；95%置信区间：最高暴露组与最低暴露组相比为-2.91%，0.36%；趋势检验 p 值=0.06）有关。我们的结果表明，产前暴露于饮用水 TBM 与脐带血中的 DNA 低甲基化有关。然而，需要进一步的研究来证实我们的发现。
