| Title: | Cost/variance optimization for human exposure assessment studies |
| Author(s): | Whitmore RW; Pellizzari ED; Zelon HS; Michael LC; Quackenboss JJ; |
| Address: | "Research Triangle Institute, PO Box 12194, Research Triangle Park, North Carolina, USA. rww@rti.org" |
| Journal Title: | J Expo Anal Environ Epidemiol |
| ISSN/ISBN: | 1053-4245 (Print) 1053-4245 (Linking) |
| Abstract: | "The National Human Exposure Assessment Survey (NHEXAS) field study in EPA Region V (one of three NHEXAS field studies) provides extensive exposure data on a representative sample of 249 residents of the Great Lakes states. Concentration data were obtained for both metals and volatile organic compounds (VOCs) from multiple environmental media and from human biomarkers. A variance model for the logarithms of concentration measurements is used to define intraclass correlations between observations within primary sampling units (PSUs) (nominally counties) and within secondary sampling units (SSUs) (nominally Census blocks). A model for the total cost of the study is developed in terms of fixed costs and variable costs per PSU, SSU, and participant. Intraclass correlations are estimated for media and analytes with sufficient sample sizes. We demonstrate how the intraclass correlations and variable cost components can be used to determine the sample allocation that minimizes cost while achieving pre-specified precision constraints for future studies that monitor environmental concentrations and human exposures for metals and VOCs" |
| Keywords: | "Biomarkers Dust *Environmental Exposure Humans Metals/toxicity Models, Theoretical Organic Chemicals/toxicity Volatilization;" |
| Notes: | "MedlineWhitmore, Roy W Pellizzari, Edo D Zelon, Harvey S Michael, Larry C Quackenboss, James J eng Research Support, U.S. Gov't, Non-P.H.S. England 2005/05/12 J Expo Anal Environ Epidemiol. 2005 Nov; 15(6):464-72. doi: 10.1038/sj.jea.7500424" |
