DOES REGRESSION-ANALYSIS OF LUNG-FUNCTION DATA OBTAINED FROM OCCUPATIONAL EPIDEMIOLOGIC STUDIES LEAD TO MISLEADING INFERENCES REGARDING THETRUE EFFECT OF SMOKING

Exposure-response studies of the relationship between ventilatory func tion and dust exposure in workers are often quantified using linear re gression methods. In coal miners, this technique has indicated that av erage effects of smoking and moderate dust exposure are roughly equiva lent. However, the validity of direct comparison of the average effect s of smoking and dust exposure has been questioned, the argument being that smoking causes severe effects in a minority, but leaves the rema inder largely unaffected. This hypothesis was studied by examining dis tributions of FEV(1) in a group of working coal miners where mean effe cts associated with both smoking and dust exposure have been detected. Overall, the results suggest that comparison of average effects of sm oking and dust exposure derived from linear regression analysis is val id and not misleading. (C) 1995 Wiley-Liss, Inc.