A nested approach to evaluating dose-response and trend.
OBJECTIVE
Conventional dose-response and trend analysis fits either a linear or categorical logistic model and tests the resulting coefficients. These analyses, however, are based on implausible assumptions.


METHODS
We present an alternative approach that uses likelihood ratio tests to compare nested regression models and determine when a model is rich enough to capture the data trends.


RESULTS
For illustration, we apply this approach to data on diet and colorectal polyps.


CONCLUSIONS
Comparison of linear and quadratic spline logistic models indicates that the conventional approach of using only a linear logistic model would not appropriately describe the association between intake of fruits and vegetables and colorectal polyps in our data. Graphical checking further supports this conclusion.
Witte
J S
JS
Department of Epidemiology and Biostatistics, School of Medicine, Case Western Reserve University, Cleveland, OH 44109-1998, USA.
Greenland
S
S
D016022:Case-Control Studies; D003111:Colonic Polyps / Q000453:epidemiology / Q000209:etiology; D004043:Dietary Fiber / Q000008:administration & dosage; D004812:Epidemiologic Methods; D005638:Fruit; D006801:Humans; D016015:Logistic Models; D012107:Research Design; D014675:Vegetables