Dr. Killian Hurley:

The advice is that smoking is a risk factor for lots of different diseases but certainly for pulmonary fibrosis, that is one of them. Exposure to different types of things like different types of dusts at work can be a risk factor for fibrosis too. Then, there are some unusual exposures. People working with different types of animals or different types of mushrooms can put them at risk of getting fibrosis. They are well-documented, but they are probably rarer types of fibrosis. We do not know the cause of the most common type of fibrosis. It usually occurs in people who are greater than the age of 60, and mostly in men. It is approximately 60% or 70% men. The main cause of fibrosis is still unknown.