Idiopathic pulmonary fibrosis (IPF) is likely caused by preventable environmental exposures in one in five cases, an Australian study suggests.

This finding, combined with the confirmation of a strong association with family history, means that people at risk need advice from their doctors on avoiding exposures that could trigger the disease, the authors say.

The case-control study comparing exposures of 503 people (69% male, mean age 71) from the Australian IPF registry with 902 age and sex-matched population controls shows that a family history of pulmonary fibrosis raises the odds of having IPF nearly 13-fold.

Having ever smoked was the next strongest association, increasing the odds of IPF more than two-fold.