AN ALTERNATIVE EXPLANATION FOR THE APPARENT ELEVATED RELATIVE MORTALITY AND MORBIDITY RISKS ASSOCIATED WITH EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE

Insofar as industrial and other blue collar workers are more likely to bring home toxic materials on their person, and also are more likely to smoke than those in other occupations, members of a household are m ore likely to be subject to paraoccupational exposure and belong to lo wer socioeconomic strata if the household contains a smoker than if th e household does not contain a smoker. Thus observed differences in ri sk of mortality or morbidity ascribed to ETS on the basis of a compari son of households with and without smokers may be partly or entirely d ue to differences in paraoccupational exposure and socioeconomic strat a. Similarly, differences in mortality and morbidity ascribed to parao ccupational exposure may be partly or entirely due to differences in E TS exposure that are also related to social class and to types of occu pation. Unfortunately, there are no data now in existence that could h elp determine separately the effects of these major confounded variabl es. There exists, then, a situation in which two explanations are adva nced for respiratory diseases among members of a household, each based on similar study populations but focused on different major risk vari ables: ETS on the one hand, socioeconomic status and paraoccupational exposure on the other. Properly focused investigations need to be init iated.