VALIDITY OF OCCUPATIONAL EXPOSURE AND SMOKING DATA OBTAINED FROM SURVIVING SPOUSES AND COLLEAGUES

The accuracy of exposure data from surrogate sources such as spouses a nd colleagues was estimated in an historical cohort of 10,059 metal wo rkers. In a 2 year period from 1986 to 1988, 118 subjects who, in 1986 , answered a questionnaire on occupational exposures and smoking habit s had died. In 1988 spouses and long-term colleagues were interviewed on the same items. Separate contingency tables were developed comparin g case and spouse/colleague responses. Percentage of concordance, sens itivity, specificity, the kappa measure of agreement, and a bias facto r (exposed to nonexposed ratio between surrogates and cohort members) were calculated. Compared with the index subjects indication, the coll eagues' and spouses' reports represented a moderately high level of co ncordance on occupational exposures, primarily for exposures with a mo derate prevalence. There was a considerable under-reporting on both oc cupational exposures and smoking habits expressed in low values of sen sitivity and bias factor values below one. The described misclassifica tion of exposure data by using surrogate information might seriously i nfluence the risk estimation and introduce bias. (C) 1996 Wiley-Liss, Inc.