Department of Physiology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China.
Department of Forensic Pathology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan 610041, People's Republic of China.
Ecotoxicol Environ Saf. 2024 Jan 15;270:115925. doi: 10.1016/j.ecoenv.2023.115925. Epub 2024 Jan 5.
Disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), have attracted attention due to their carcinogenic properties, leading to varying conclusions. This meta-analysis aimed to evaluate the dose-response relationship and the dose-dependent effect of DBPs on cancer risk. We performed a selective search in PubMed, Web of Science, and Embase databases for articles published up to September 15th, 2023. Our meta-analysis eventually included 25 articles, encompassing 8 cohort studies with 6038,525 participants and 10,668 cases, and 17 case-control studies with 10,847 cases and 20,702 controls. We observed a positive correlation between increased cancer risk and higher concentrations of total trihalomethanes (TTHM) in water, longer exposure durations, and higher cumulative TTHM intake. These associations showed a linear trend, with relative risks (RRs) and 95 % confidence intervals (CIs) being 1.02 (1.01-1.03), 1.04 (1.02-1.06), and 1.02 (1.00-1.03), respectively. Gender-specific analyses revealed slightly U-shaped relationships in both males and females, with males exhibiting higher risks. The threshold dose for TTHM in relation to cancer risk was determined to be 55 µg/L for females and 40 µg/L for males. A linear association was also identified between bladder cancer risk and TTHM exposure, with an RR and 95 % CI of 1.08 (1.05-1.11). Positive linear associations were observed between cancer risk and exposure to chloroform, bromodichloromethane (BDCM), and HAA5, with RRs and 95 % CIs of 1.02 (1.01-1.03), 1.33 (1.18-1.50), and 1.07 (1.03-1.12), respectively. Positive dose-dependent effects were noted for brominated THMs above 35 µg/L and chloroform above 75 µg/L. While heterogeneity was observed in the studies for quantitative synthesis, no publication bias was detected. Exposure to TTHM, chloroform, BDCM, or HAA5 may contribute to carcinogenesis, and the risk of cancer appears to be dose-dependent on DBP exposure levels. A cumulative effect is suggested by the positive correlation between TTHM exposure and cancer risk. Bladder cancer and endocrine-related cancers show dose-dependent and positive associations with TTHM exposure. Males may be more susceptible to TTHM compared to females.
消毒副产物（DBPs），包括三卤甲烷（THMs）和卤乙酸（HAAs），由于其致癌特性而引起关注，导致了不同的结论。本荟萃分析旨在评估 DBPs 对癌症风险的剂量-反应关系和剂量依赖性效应。我们在 PubMed、Web of Science 和 Embase 数据库中进行了选择性搜索，以获取截至 2023 年 9 月 15 日发表的文章。我们的荟萃分析最终纳入了 25 篇文章，其中包括 8 项队列研究，涉及 6038525 名参与者和 10668 例病例，以及 17 项病例对照研究，涉及 10847 例病例和 20702 例对照。我们观察到，癌症风险与水中总三卤甲烷（TTHM）浓度升高、暴露时间延长和 TTHM 累积摄入量增加呈正相关。这些关联呈线性趋势，相对风险（RR）和 95%置信区间（CI）分别为 1.02（1.01-1.03）、1.04（1.02-1.06）和 1.02（1.00-1.03）。性别特异性分析显示，男性和女性均呈现出略微的 U 形关系，男性的风险更高。TTHM 与癌症风险相关的阈值剂量确定为女性 55μg/L，男性 40μg/L。还发现膀胱癌风险与 TTHM 暴露之间存在线性关联，RR 和 95%CI 为 1.08（1.05-1.11）。还观察到 TTHM 暴露与癌症风险之间存在正线性关联，RR 和 95%CI 分别为 1.02（1.01-1.03）、1.33（1.18-1.50）和 1.07（1.03-1.12）。暴露于三氯甲烷、溴二氯甲烷（BDCM）和 HAA5 与癌症风险呈正线性关联，RR 和 95%CI 分别为 1.02（1.01-1.03）、1.33（1.18-1.50）和 1.07（1.03-1.12）。TTHM 高于 35μg/L 和三氯甲烷高于 75μg/L 时，观察到溴化 THMs 的阳性剂量依赖性效应。尽管在定量综合研究中存在异质性，但未检测到发表偏倚。TTHM、三氯甲烷、BDCM 或 HAA5 的暴露可能导致致癌，癌症风险似乎与 DBPs 暴露水平呈剂量依赖性。TTHM 暴露与癌症风险之间的正相关提示存在累积效应。膀胱癌和内分泌相关癌症与 TTHM 暴露呈剂量依赖性和正相关。与女性相比，男性可能更容易受到 TTHM 的影响。
