In a recently published multicentre case–control study evaluating lung cancer risk among subjects exposed to organic dusts,1 the authors could not confirm the findings from previous reports in which a decreased risk was found among workers in the cotton industry and animal farmers.2

Regarding a decreased risk of lung cancer among cotton workers3–7 the authors quite rightly concluded that their material was not suitable to evaluate this relationship as their subgroups did not reflect the critical exposure groups, i.e. those exposed to high levels of endotoxin such as cardroom workers and weavers.8

For farmers we believe that the multicentre case–control study findings have the same shortcomings …