Idiopathic means the cause is not known, but researchers now believe that the body creates fibrosis (scarring) in response to an injury to the lung.

The initial injury to the lungs might be from:

  • acid reflux from the stomach
  • viruses - in some studies, IPF has been linked to certain viruses, including herpes, hepatitis C and the Epstein Barr virus, which causes glandular fever
  • environmental factors - breathing in certain kinds of dust from wood, metal, textiles or stone, or from cattle or farming
  • cigarette smoke exposure.

It is not known if these factors directly cause IPF.

Some people may also get IPF if it’s in their family history. But this link is only found in a minority of cases. According to a 2021 survey by the British Thoracic Society, 5.7% of patients were found to have a known relative with IPF.

Who gets IPF?

IPF is more common in people over the age of 40. It is also more common in men that it is in women.

Read next: symptoms of IPF

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