SOME STATISTICAL CONSIDERATIONS IN THE ANALYSIS OF CASE-CONTROL STUDIES WHEN THE EXPOSURE VARIABLES ARE CONTINUOUS MEASUREMENTS

This paper focuses on some statistical considerations in the estimatio n of dose response in case control studies when the exposure variables are continuous measurements. The first point is that the-effects of d ifferential variability in the exposure distributions over cases and c ontrols cannot be differentiated from a true quadratic risk model. The second point is that when dealing with variables where zero denotes n o exposure, it is important to treat the unexposed subjects separately from those who were exposed. Failure to do so can lead to differentia l variability among cases and controls and the resulting confounding w ith a quadratic risk model. Both of these points are illustrated by an example.