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Int. J. Environ. Res. Public Health 2011, 8(10), 4082-4101; doi:10.3390/ijerph8104082
Article

Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region

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Received: 25 March 2011; in revised form: 21 September 2011 / Accepted: 30 September 2011 / Published: 24 October 2011
(This article belongs to the Special Issue Environmental Health Risk Assessment)
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Abstract: In complex mixture toxicology, there is growing emphasis on testing environmentally representative doses that improve the relevance of results for health risk assessment, but are typically much lower than those used in traditional toxicology studies. Traditional experimental designs with typical sample sizes may have insufficient statistical power to detect effects caused by environmentally relevant doses. Proper study design, with adequate statistical power, is critical to ensuring that experimental results are useful for environmental health risk assessment. Studies with environmentally realistic complex mixtures have practical constraints on sample concentration factor and sample volume as well as the number of animals that can be accommodated. This article describes methodology for calculation of statistical power for non-independent observations for a multigenerational rodent reproductive/developmental bioassay. The use of the methodology is illustrated using the U.S. EPA’s Four Lab study in which rodents were exposed to chlorinated water concentrates containing complex mixtures of drinking water disinfection by-products. Possible experimental designs included two single-block designs and a two-block design. Considering the possible study designs and constraints, a design of two blocks of 100 females with a 40:60 ratio of control:treated animals and a significance level of 0.05 yielded maximum prospective power (~90%) to detect pup weight decreases, while providing the most power to detect increased prenatal loss.
Keywords: power calculations; experimental design; drinking water; disinfection by-products (DBP); chemical mixtures; low response; low dose; Four Lab Study power calculations; experimental design; drinking water; disinfection by-products (DBP); chemical mixtures; low response; low dose; Four Lab Study
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Dingus, C.A.; Teuschler, L.K.; Rice, G.E.; Simmons, J.E.; Narotsky, M.G. Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region. Int. J. Environ. Res. Public Health 2011, 8, 4082-4101.

AMA Style

Dingus CA, Teuschler LK, Rice GE, Simmons JE, Narotsky MG. Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region. International Journal of Environmental Research and Public Health. 2011; 8(10):4082-4101.

Chicago/Turabian Style

Dingus, Cheryl A.; Teuschler, Linda K.; Rice, Glenn E.; Simmons, Jane Ellen; Narotsky, Michael G. 2011. "Prospective Power Calculations for the Four Lab Study of A Multigenerational Reproductive/Developmental Toxicity Rodent Bioassay Using A Complex Mixture of Disinfection By-Products in the Low-Response Region." Int. J. Environ. Res. Public Health 8, no. 10: 4082-4101.



Int. J. Environ. Res. Public Health EISSN 1660-4601 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert