Methodology
Global, local and focused geographic clustering for case-control data with residential histories
-
* Corresponding author: Geoffrey M Jacquez jacquez@biomedware.com
1 BioMedware, Inc., 516 North State Street, Ann Arbor, MI, 48104-1236, USA
2 Department of Environmental Health Sciences, The University of Michigan School of Public Health, 109 S. Observatory St. Ann Arbor, MI, 48109-2029, USA
Environmental Health: A Global Access Science Source 2005, 4:4 doi:10.1186/1476-069X-4-4
Published: 22 March 2005Abstract
Background
This paper introduces a new approach for evaluating clustering in case-control data that accounts for residential histories. Although many statistics have been proposed for assessing local, focused and global clustering in health outcomes, few, if any, exist for evaluating clusters when individuals are mobile.
Methods
Local, global and focused tests for residential histories are developed based on sets of matrices of nearest neighbor relationships that reflect the changing topology of cases and controls. Exposure traces are defined that account for the latency between exposure and disease manifestation, and that use exposure windows whose duration may vary. Several of the methods so derived are applied to evaluate clustering of residential histories in a case-control study of bladder cancer in south eastern Michigan. These data are still being collected and the analysis is conducted for demonstration purposes only.
Results
Statistically significant clustering of residential histories of cases was found but is likely due to delayed reporting of cases by one of the hospitals participating in the study.
Conclusion
Data with residential histories are preferable when causative exposures and disease latencies occur on a long enough time span that human mobility matters. To analyze such data, methods are needed that take residential histories into account.