Investigation of excess environmental risk around putative sources: Stone's test with covariate adjustment
✍ Scribed by Tony Morton-Jones; Peter Diggle; Paul Elliott
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 106 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0277-6715
No coin nor oath required. For personal study only.
✦ Synopsis
Stone (Statistics in
Medicine, 7, 649-660 (1988)
) proposed a method of testing for elevation of disease risk around a point source. Stone's test is appropriate to data consisting of counts of the numbers of cases, ½ G say, in each of n regions which can be ordered in increasing distance from a point source. The test assumes that the ½ G are mutually independent Poisson variates, with means
where the E G are the expected numbers of cases, for example based on appropriately standardized national incidence rates, and the G are relative risks. The null hypothesis that the G are constant is then tested against the alternative that they are monotone non-increasing with distance from the source. We propose an extension to Stone's test which allows for covariate adjustment via a log-linear model,
), where the x GH are the values of each of p explanatory variables in each of the n regions, and the H are unknown regression parameters. Our methods are illustrated using data on the incidence of stomach cancer near two municipal incinerators.