Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA.
U.S. Environmental Protection Agency, National Center for Environmental Assessment, Cincinnati, Ohio, USA.
Occup Environ Med. 2018 Oct;75(10):742-751. doi: 10.1136/oemed-2017-104861. Epub 2018 Jul 30.
We examined stillbirths in relation to disinfection by-product (DBP) exposures including chloroform, bromodichloromethane (BDCM), dibromochloromethane, bromoform, trichloroacetic acid, dichloroacetic acid (DCAA), monobromoacetic acid and summary DBP measures (trihalomethanes (THM4), haloacetic acids (HAA5), THMBr (brominated trihalomethanes) and DBP9 (sum of THM4 and HAA5)).
We randomly selected 10 controls for each of the 2460 stillbirth cases with complete quarterly 1997-2004 THM4 and HAA5 town-level drinking water data. Adjusted (aORs) were calculated based on weight-averaged second-trimester DBP exposures.
We detected statistically significant associations for stillbirths and the upper DCAA quartiles (aOR range: 1.50-1.71). We also found positive associations for the upper four HAA5 quintiles and different stillbirth cause of death categories that were examined including unexplained stillbirth (aOR range: 1.24-1.72), compression of umbilical cord (aOR range: 1.08-1.94), prematurity (aOR range: 1.37-2.88), placental separation and haemorrhage (aOR range: 1.44-2.01) and asphyxia/hypoxia (aOR range: 1.52-1.97). Additionally, we found positive associations between stillbirths and chloroform exposure (aOR range: 1.29 - 1.36) and unexplained stillbirths and BDCM exposure (aOR range: 1.51 - 1.78). We saw no evidence of exposure-response relationships for any categorical DBP metrics.
Consistent with some previous studies, we found associations between stillbirths and chloroform and unexplained stillbirth and BDCM exposures. These findings strengthen existing evidence of prenatal THM exposures increasing the risk of stillbirth. Additionally, we saw statistically significant associations between DCAA and stillbirth. Future research should examine cause-specific stillbirths in relation to narrower critical windows and additional DBP exposure metrics beyond trihalomethanes and haloacetic acids.
我们研究了与消毒副产物（DBP）暴露相关的死胎，包括三氯甲烷、溴二氯甲烷（BDCM）、二溴氯甲烷、溴仿、三氯乙酸、二氯乙酸（DCAA）、一溴乙酸和 DBP 总和（三卤甲烷（THM4）、卤乙酸（HAA5）、THMBr（溴化三卤甲烷）和 DBP9（THM4 和 HAA5 的总和））。
我们随机选择了 1997 年至 2004 年每个季度完整的 2460 例死胎病例中的 10 个对照，这些病例具有完整的城镇级饮用水 THM4 和 HAA5 数据。根据加权平均妊娠中期 DBP 暴露值计算了调整后的比值比（aOR）。
我们检测到与死胎和 DCAA 上四分位（aOR 范围：1.50-1.71）相关的统计学显著关联。我们还发现与四个 HAA5 五分位上限和不同的死胎死因类别呈正相关，这些死因类别包括不明原因的死胎（aOR 范围：1.24-1.72）、脐带受压（aOR 范围：1.08-1.94）、早产（aOR 范围：1.37-2.88）、胎盘分离和出血（aOR 范围：1.44-2.01）和窒息/缺氧（aOR 范围：1.52-1.97）。此外，我们发现与三氯甲烷暴露（aOR 范围：1.29-1.36）之间存在死胎和不明原因死胎与 BDCM 暴露（aOR 范围：1.51-1.78）之间存在正相关。我们没有发现任何分类 DBP 指标存在暴露-反应关系的证据。
与一些先前的研究一致，我们发现死胎与三氯甲烷以及不明原因的死胎与 BDCM 暴露之间存在关联。这些发现加强了产前三卤甲烷暴露增加死胎风险的现有证据。此外，我们还发现 DCAA 与死胎之间存在统计学显著关联。未来的研究应在更窄的关键窗口期内，针对特定原因的死胎，并考虑除三卤甲烷和卤乙酸以外的其他 DBP 暴露指标，进一步研究两者之间的关系。
