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Categorical Regression Analysis of Acute Exposure to Tetrachloroethylene 1
Author(s) -
Guth Daniel J.,
Carroll Raymond J.,
Simpson Douglas G.,
Zhou Haibo
Publication year - 1997
Publication title -
risk analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.972
H-Index - 130
eISSN - 1539-6924
pISSN - 0272-4332
DOI - 10.1111/j.1539-6924.1997.tb00870.x
Subject(s) - categorical variable , tetrachloroethylene , regression analysis , statistics , regression , linear regression , ordinal data , ordinal regression , multilevel model , mathematics , chemistry , environmental chemistry , trichloroethylene
Exposure‐response analysis of acute noncancer risks should consider both concentration (C) and duration (T) of exposure, as well as severity of response. Stratified categorical regression is a form of meta‐analysis that addresses these needs by combining studies and analyzing response data expressed as ordinal severity categories. A generalized linear model for ordinal data was used to estimate the probability of response associated with exposure and severity category. Stratification of the regression model addresses systematic differences among studies by allowing one or more model parameters to vary across strata denned, for example, by species and sex. The ability to treat partial information addresses the difficulties in assigning consistent severity scores. Studies containing information on acute effects of tetrachloroethylene in rats, mice, and humans were analyzed. The mouse data were highly uncertain due to lack of data on effects of low concentrations and were excluded from the analysis. A model with species‐specific concentration intercept terms for rat and human central nervous system data improved fit to the data compared with the base model (combined species). More complex models with strata denned by sex and species did not improve the fit. The stratified regression model allows human effect levels to be identified more confidently by basing the intercept on human data and the slope parameters on the combined data (on a C × T plot). This analysis provides an exposure–response function for acute exposures to tetrachloroethylene using categorical regression analysis.