| Community-Based Randomized Double-Blind Study of Gastrointestinal Effect and Copper Exposure in Drinking Water Magdalena Araya, Manuel Olivares, Fernando Pizarro, Adolfo Llanos, Guillermo Figueroa, and Ricardo Uauy Institute of Nutrition and Food Technology, University of Chile, Santiago, Chile Abstract
We assessed gastrointestinal effects in 1,365 adults exposed to either < 0.01 (controls) , 2, 4, or 6 mg copper/L of drinking water for 2 months in a randomized, double-blind community-based study. The risk of symptoms increased with increasing Cu exposure and decreased with time. The best model by counting-process analysis included Cu concentration and sex. The risk of symptoms remained significantly higher in women than in men during weeks 1-4 for all concentrations tested ; at week 1 comparison with the < 0.01-mg/L group showed that differences became significant in women at 4 mg/L [relative risk (RR) = 1.53 ; 95% confidence interval (CI) , 1.02-2.05) , and in men at 6 mg/L (RR = 1.9 ; 95% CI, 1.02-2.79) . At week 2 for men and week 4 in women, the Cu concentration required to obtain significant differences on symptom report was > 6 mg Cu/L. We conclude that exposure to Cu in drinking water results in gastrointestinal symptoms, which are modulated by Cu concentration, time, and sex. Key words: adults, copper, drinking water, exposure, nausea. Environ Health Perspect 112:1068-1073 (2004) . doi:10.1289/ehp.6913 available via http://dx.doi.org/ [Online 31 March 2004]
Address correspondence to M. Araya, Institute of Nutrition and Food Technology, Macul 5540, Santiago 11, Chile. Telephone: (56-2) 678-1472. Fax: (56-2) 221-4030. E-mail maraya@uec.inta.uchile.cl We thank the International Technical Advisory Group (ITAG) , and N. Diaz and B. Lyon for their helpful assistance in statistical analyses. This investigation was funded by Corporación Chilena del Cobre (COCHILCO) in the form of an unrestricted grant. At the request of the Chilean Ministry of Health, the Pan American Health Organization (PAHO) formed an ITAG for this study. The ITAG provided advice to the research team on the study protocol, the conduct of the study, and analysis and interpretation of the results. The ITAG drew from a range of technical expertise from North America and Europe. The members of ITAG and PAHO do not necessarily endorse the conclusions of the study ; similarly, participation of these scientific experts in the ITAG does not necessarily imply endorsement of the conclusions by the agencies or institutions of the individual experts. The authors declare they have no competing financial interests. Received 11 December 2003 ; accepted 31 March 2004.
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