American Journal of Epidemiology Advance Access originally published online on November 9, 2005
American Journal of Epidemiology 2006 163(1):38-47; doi:10.1093/aje/kwj009
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Original Contribution |
Estimated Effects of Disinfection By-products on Birth Weight in a Population Served by a Single Water Utility
1 Environmental Science and Engineering Program, Department of Environmental Health Sciences, School of Public Health, University of California, Los Angeles, CA
2 Department of Epidemiology, School of Public Health, University of California, Los Angeles, CA
3 Department of Environmental Health Sciences, School of Public Health, University of California, Los Angeles, CA
Correspondence to Chad Lewis, 8 Pinewood Avenue, Natick, MA 01760 (e-mail: myta_3{at}yahoo.com).
Research has suggested that trihalomethane exposures during pregnancy might impair fetal growth. Most epidemiologic studies, however, relied on relatively crude exposure assessment methods and did not examine racial/ethnic subgroups. During 1999–2001, vital records data were obtained for a large, racially diverse population residing in 27 Massachusetts communities that received drinking water from a single public utility. The water system was monitored weekly for trihalomethanes and, system-wide, it maintained geographically stable total trihalomethane levels during the study period. The authors examined the effects of trimester-specific and pregnancy average exposures to total trihalomethane in drinking water on term low birth weight in all singleton births. A high average total trihalomethane exposure (
70 µg/liter) during the second trimester increased the risk of term low birth weight (odds ratio = 1.50, 95% confidence interval (CI): 1.07, 2.10). The estimated risk increase for Caucasians during the second trimester was 37% (95% CI: 0.80, 2.36), while for all minority women combined (i.e., African Americans, Hispanics, and Asians) it was 60% (95% CI: 1.03, 2.47). The study data suggest that high levels (70 µg/liter) of trihalomethanes experienced during the second trimester and pregnancy overall may affect fetal growth.
birth weight; chloroform; environmental exposure; fetal growth retardation; pregnancy trimester, second; trihalomethanes; water
Abbreviations: CI, confidence interval; OR, odds ratio; TLBW, term low birth weight