| Relation of Trihalomethane Concentrations in Public Water Supplies to Stillbirth and Birth Weight in Three Water Regions in England Mireille B. Toledano,1 Mark J. Nieuwenhuijsen,1,2 Nicky Best,1 Heather Whitaker,1,3 Peter Hambly,1 Cornelis de Hoogh,1 John Fawell,4 Lars Jarup,1 and Paul Elliott1 1Small Area Health Statistics Unit, Department of Epidemiology and Public Health, Faculty of Medicine, and 2Department of Environmental Science and Technology, Imperial College London, London, United Kingdom; 3Department of Statistics, Open University, Milton Keynes, United Kingdom; 4Independent Consultant, Buckinghamshire, United Kingdom Abstract
We investigated the association between total trihalomethanes (TTHMs) and risk of stillbirth and low and very low birth weight in three water regions in England, 1992-1998 ; associations with individual trihalomethanes (THMs) were also examined. Modeled estimates of quarterly TTHM concentrations in water zones, categorized as low (< 30 µg/L) , medium (30-59 µg/L) , or high ( 60 µg/L) , were linked to approximately 1 million routine birth and stillbirth records using maternal residence at time of birth. In one region, where there was a positive socioeconomic deprivation gradient across exposure categories, there was also a positive, significant association of TTHM with risk of stillbirth and low and very low birth weight. Overall summary estimates across the three regions using a random-effects model to allow for between-region heterogeneity in exposure effects showed small excess risks in areas with high TTHM concentrations for stillbirths [odds ratio (OR) = 1.11 ; 95% confidence interval (CI) , 1.00-1.23) , low birth weight (OR = 1.09 ; 95% CI, 0.93-1.27) , and very low birth weight (OR = 1.05 ; 95% CI, 0.82-1.34) . Among the individual THMs, chloroform showed a similar pattern of risk as TTHM, but no association was found with concentrations of bromodichloromethane or total brominated THMs. Our findings overall suggest a significant association of stillbirths with maternal residence in areas with high TTHM exposure. Further work is needed looking at cause-specific stillbirths and effects of other disinfection by-products and to help differentiate between alternative (noncausal) explanations and those that may derive from the water supply. Key words: chemical, disinfection, infant low birth weight, pregnancy outcome, stillbirth, trihalomethanes, water pollution, water purification. Environ Health Perspect 113:225-232 (2005) . doi:10.1289/ehp.7111 available via http://dx.doi.org/ [Online 21 October 2004]
Address correspondence to P. Elliott, Department of Epidemiology and Public Health, Faculty of Medicine, Imperial College London, St. Mary's Campus, Norfolk Pl., London W2 1PG, UK. Telephone: 44-0-20-7594-3328. Fax: 44-0-20-7402-2150. E-mail: p.elliott@imperial.ac.uk We thank the following for their helpful contribution to the study: A. Gowers, J. Bennett, I. Maitland, N. Cobley, K. Konstantinou, D. Fecht, S. Cockings, D. Briggs, V. Barnard, and S. Fawell. We are also grateful to Northumbrian Water, United Utilities Water (formerly North West) , and Severn Trent Water for providing the trihalomethane data and to the Office for National Statistics for providing the health data used in the study. The Small Area Health Statistics Unit is funded by a grant from the Department of Health, Department of the Environment, Food and Rural Affairs, Environment Agency, Health and Safety Executive, Scottish Executive, Welsh Assembly Government and Northern Ireland Department of Health, Social Services and Public Safety. The views expressed in this publication are those of the authors and not necessarily those of the funding departments. The authors declare they have no competing financial interests. J. Fawell consults on issues relating to water supply and safety for both government and industry. Received 23 March 2004 ; accepted 21 October 2004.
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