Individual exposures to drinking water trihalomethanes, low birth weight and small for gestational age risk: a prospective Kaunas cohort study

Abstract

BackgroundEvidence for an association between exposure during pregnancy to trihalomethanes (THMs) in drinking water and impaired fetal growth is still inconsistent and inconclusive, in particular, for various exposure routes. We examined the relationship of individual exposures to THMs in drinking water on low birth weight (LBW), small for gestational age (SGA), and birth weight (BW) in singleton births.MethodsWe conducted a cohort study of 4,161 pregnant women in Kaunas (Lithuania), using individual information on drinking water, ingestion, showering and bathing, and uptake factors of THMs in blood, to estimate an internal dose of THM. We used regression analysis to evaluate the relationship between internal THM dose and birth outcomes, adjusting for family status, education, smoking, alcohol consumption, body mass index, blood pressure, ethnic group, previous preterm, infant gender, and birth year.ResultsThe estimated internal dose of THMs ranged from 0.0025 to 2.40 mg/d. We found dose-response relationships for the entire pregnancy and trimester-specific THM and chloroform internal dose and risk for LBW and a reduction in BW. The adjusted odds ratio for third tertile vs. first tertile chloroform internal dose of entire pregnancy was 2.17, 95% CI 1.19-3.98 for LBW; the OR per every 0.1 μg/d increase in chloroform internal dose was 1.10, 95% CI 1.01-1.19. Chloroform internal dose was associated with a slightly increased risk of SGA (OR 1.19, 95% CI 0.87-1.63 and OR 1.22, 95% CI 0.89-1.68, respectively, for second and third tertile of third trimester); the risk increased by 4% per every 0.1 μg/d increase in chloroform internal dose (OR 1.04, 95% CI 1.00-1.09).ConclusionsTHM internal dose in pregnancy varies substantially across individuals, and depends on both water THM levels and water use habits. Increased internal dose may affect fetal growth.

Drinking Water Disinfection By-products, Genetic Polymorphisms, and Birth Outcomes in a European Mother–Child Cohort Study

“…A separate model was built in each country (region in the case of Spain) for total trihalomethanes, chloroform, and total brominated trihalomethanes following similar methods as discussed in study-specific published papers. [8][9][10]17,18 Linear regression and generalized additive models were fitted using geographical and temporal variables (month, year). Among models retaining significant variables (p value<0.05), criteria to select the final model included the adjusted R-squared and the Akaike Information Criteria.…”

“…15,16 Analyses of the association of trihalomethanes with birth outcomes for country-specific populations included in HiWate (Health Impacts of Long-Term Exposure to Disinfection By-Products in Drinking Water) have been published previously. 8,9,10,17,18 …”

Occurrence of Trihalomethanes in Chlorinated Waters from Different Sources Used for Urban Supply

“…Nevertheless, when individual values are analyzed, all samples presented concentrations of BDCM and TBM above zero, which is the maximum contaminant level goal for these two compounds. High THMs values usually occur at points in the distribution system with the longest residence time or water age, such as reservoirs, oversized pipes and network dead ends [9]. Figure 2 presents the mean results of samples grouped by five main geographical areas.…”

“…In 2011, Regina Grazuleviciene et al found epidemiological evidence for a dose-response relationship between the THMs blood internal dose of pregnant women, exposed through drinking water by ingestion, showering and bathing, and child low birth weight found epidemiological evidence for a dose-response relationship between THM internal dose exposure and low birth weight [9]. Identical conclusions were achieved by Iszatt N. et al in 2014 suggesting that a high decrease in chloroform concentrations in tap water is associated with a statistically significant reduction in very low birth weight rates [10].…”

Environmental Exposures, Genetic Susceptibility and Preterm Birth

“…Seeking to improve the exposure assessment, studies have begun to incorporate behavioural determinants of different routes of exposure to DBPs such as dermal absorption and inhalation during bathing and showering, and ingestion of drinking water (Savitz et al 2006;Hoffman et al, 2008;MacLehose et al, 2008). In our previous prospective Kaunas cohort study, which incorporated of different routes of exposure to THMs, we found doseresponse relationships for entire pregnancy and trimester-specific gestational THMs and chloroform internal dose for low birth weight and reduction in birth weight (Grazuleviciene et al, 2011). The epidemiological studies concluded that, while there appears to be suggestive evidence associating elevated total THM levels with some adverse reproductive outcomes, evidence for relationships with preterm birth and fetal growth is inconclusive and inconsistent (Richardson et al, 2003;Lewis et al, 2006;Grellier et al, 2010).…”