Dose-response relationship between amphibole fiber lung burden and mesothelioma

In a mesothelioma case-control study, asbestos and other mineral fibers fro m lung burden were examined as causal factors. Diagnosis was confirmed by a panel of pathologists. For 66 cases and 66 controls from hospitals in five German towns, lung tissue fiber analysis by transmission electron microsco py was available. Control patients were treated by a surgical lung resectio n mostly because of lung cancer. For chrysotile and other mineral fibers a significantly increased odds ratio (OR) was not observed. A clear dose-resp onse relationship was demonstrated for the concentration C-A of amphibole f ibers longer than 5 mu m Between 0.025 and 2.5 fibers/mu g dry weight (f/mu g) the relationship can be approximated as OR = C-A/(0.025 f/mu g). Simila r but less distinct dose-response relationships were found in a Canadian an d an Australian study. It is concluded that among German mesothelioma patie nts factors not associated with amphibole fiber concentration are not predo minating.