ASBESTOS EXPOSURE AND THE RISK OF LUNG-CANCER IN A GENERAL URBAN-POPULATION

OBJECTIVES - The aim of the study was to investigate the asbestos-asso ciated risk of lung cancer according to histological type of cancer, l obe of origin, pulmonary concentration, and type of amphi bole fibers and also to estimate the etiologic fraction of asbestos for lung cance r. METHODS - The pulmonary concentration of asbestos fibers in 113 sur gically treated male lung cancer patients and 297 autopsy cases among men serving as referents was determined by scanning electron microscop y. The age- and smoking-adjusted odds ratios of lung cancer were calcu lated according to pulmonary fiber concentration for all lung cancer t ypes, sqaumous-cell carcinoma, and adenocarcinoma and for the lower-lo be and the upper- and middle-lobe cancers. RESULTS - The risk of lung cancer was increased according to the pulmonary concentration of asbes tos fibers (f) of 1.0 to 4.99 . 10(6) f . g(-1) [odds ratio (OR) 1.7] and greater than or equal to 5.0 . 10(6) f . g(-1) (OR 5.3). The odds ratios associated with fiber concentrations of greater than or equal t o 1.0 . 10(6) f . g(-1) were higher for adenocarcinoma (OR 4.0) than f or squamous-cell carcinoma (OR 1.6). The asbestos-associated risk was higher for lower lobe tumors than for upper lobe tumors. The risk esti mates for anthophyllite and crocidolite-amosite fibers were similar, e xcept for the risk of squamous-cell carcinoma. An etiologic fraction o f 19% was calculated for asbestos among male surgical lung cancer pati ents in the greater Helsinki area. CONCLUSIONS - Past exposure to asbe stos is a significant factor in the etiology of lung cancer in souther n Finland. The asbestos-associated risk seems to be higher for pulmona ry adenocarcinoma and lower-lobe tumors than for squamous-cell carcino ma and upper-lobe tumors.