ENVIRONMENTAL TOBACCO-SMOKE AND CHILDHOOD ASTHMA - COMPARING EXPOSUREMETRICS USING PROBABILITY PLOTS

This study demonstrates the use of probability plots for assessing exp osure-disease relationships in case-control studies. We reanalyze data from a study of childhood asthma and exposure to environmental tobacc o smoke, comparing alternative measures of smoking intensity. Previous analyses showed a higher mean urinary cotinine-to-creatinine ratio (C CR) in cases as compared with controls and a statistically significant odds ratio with exposure defined as 30 ng/mg CCR or higher. Using pro bability plots, we compare alternative exposure metrics and exposure c utpoints with respect to their ability to detect a statistically signi ficant exposure-disease effect. A strong exposure-disease response is evident, overall, and the results are fairly robust to the choice of e xposure cutpoint. (C) 1994 Academic Press, Inc.