In their publication based on a case–control study of pleural mesothelioma in Casale Monferrato, Ferrante et al1 reported associations with occupational and non-occupational (household and residential) exposure to asbestos. From a qualitative point of view, these results are hardly surprising since similar findings have been reported in several other populations with heavy asbestos exposure (for review see ref. 2).

The main emphasis of the publication, however, rests on quantitative estimates of these associations. However, the results suffer from important limitations, and these limit their interpretation. Response rate was 89% among cases and 63% among controls, and the proportion of interviews …