Asbestos and man-made vitreous fibers as risk factors for diffuse malignant mesothelioma: results from a German hospital-based case-control study.
BACKGROUND
This study examines the role of occupational factors in the development of diffuse malignant mesothelioma with special emphasis on the dose-response relationship for asbestos and on the exposure to man-made vitreous fibers (MMVFs).


METHODS
One hundred and twenty-five male cases, diagnosed by a panel of pathologists, were personally interviewed concerning their occupational and smoking history. The same number of population controls (matched for sex, age and region of residence) underwent similar interviews by trained interviewers. Odds ratios (OR) were calculated for an expert-based exposure index using conditional logistic regression.


RESULTS
Exposure to asbestos shows the expected sharp gradient with an OR of about 45 for a cumulative exposure > 1.5 fiber years (arithmetic mean 16 fiber years). A significant OR was calculated even for the lowest exposure category "> 0 - < or = 0.15 fiber years". Although the mean cumulative exposure to MMVF is roughly 10% of the exposure to asbestos, an increased OR is observed in an ever/never evaluation. This observation is heavily hampered by methodical problems. A corresponding case-control study was performed using a lung tissue fiber analysis in addition to interviews. Both interviews and the lung tissue analysis yielded similar OR levels between the reference and the maximum exposure intervals.


CONCLUSIONS
Despite a possible influence as a result of selection and information bias, our results confirm the previously reported observation of a distinct dose-response relationship even at levels of cumulative exposure below 1 fiber year. Moreover, the study confirms that asbestos is a relevant confounder for MMVF. A causal relationship between exposure to MMVF and mesothelioma could neither be detected nor excluded, as in other studies.
Institute and Outpatient Clinic for Occupational and Social Medicine, University of Giessen, Germany. Klaus.Roedelsperger@arbmed.med.uni-giessen.de
K
K
Rödelsperger
K H
KH
Jöckel
H
H
Pohlabeln
W
W
Römer
H J
HJ
Woitowitz
D000368:Aged; D001194:Asbestos / Q000009:adverse effects*; D016022:Case-Control Studies; D005858:Germany; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008297:Male; D008420:Manufactured Materials / Q000009:adverse effects*; D008654:Mesothelioma / Q000209:etiology*; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects; D012307:Risk Factors; D013997:Time Factors
D001194:Asbestos