No effect or no information? Comments on a nested case-control study of lung cancer among European rock and slag wool production workers.

The author considers the validity of a recent study of lung cancer among European rock and slag wool workers. The study failed to demonstrate an association between lung cancer and exposure to man-made vitreous fibers and also did not manage to demonstrate a relationship between lung cancer and asbestos exposure, an odd finding that casts doubt on its validity. This article deals with bias towards the null and other aspects of the reviewed study that may explain its failure to demonstrate an effect of asbestos, concluding that the study does not add to knowledge about a possible carcinogenic effect of rock and slag wool fibers, the apparent null results simply being non-informative because of the study's poor ability to detect existing associations.