What is Idiopathic Pulmonary Fibrosis and What are the Causes?

Overview of Idiopathic Pulmonary Fibrosis

diagram showing the changes of idiopathic pulmonary fibrosis in the lungs
Idiopathic pulmonary fibrosis is a rare and fatal disease. National Heart Lung and Blood Institute

If you or a loved one have been diagnosed with idiopathic pulmonary fibrosis (IPF) you are probably very frightened. Very few people are familiar with this uncommon disease, but what can be most frightening is if you google old information on IPF. Until 2014 there weren’t really any treatments available that made a significant difference for people living with the disease.Thankfully, that’s changing.

 Now there IS treatment for this disease that is improving lives.

What is Idiopathic Pulmonary Fibrosis (IPF)?

IPF is the most common form of a group of diseases known as idiopathic interstitial pneumonia. The term interstitial means that the condition if present is in the areas of the lungs between the alveoli (alveoli are the tiny air sacs at the end of the respiratory tree where the exchange of oxygen and carbon dioxide takes place) and in the alveolar linings. Fibrosis simply means scarring. It is this scarring in alveolar walls and the tissues between them which interferes with the ability of oxygen to pass through the walls of the alveoli and into the bloodstream.

In the past, it had been thought that IPF was an inflammatory process. Now it’s thought that it begins with damage to the lungs from a combination of sources, followed by abnormal healing—fibrosis. To imagine what this is like , imagine a cut on your skin which heals with a scar.

 In many people, a cut heals with a fine red line that turns white with time.  In some people, the skin heals abnormally leaving a thickened and unsightly keloid scar. The fibrosis in IPF is similar to this type of scarring, but not visible outside of the body.

In addition to being a progressive disease on its own, 10 percent of people with IPF are expected to develop lung cancer.

How Common is IPF?

Numbers vary when looking at the incidence of idiopathic pulmonary fibrosis, but the consensus is that the condition is underdiagnosed; many people likely have IPF which is diagnosed as another condition, or who pass away before the diagnosis is made.

Based on one analysis in the United States, it was found that the incidence (number of people diagnosed each year) of IPF was 58.7 per 100,000 people. In another 2011 study, it was found that the prevalence (number of people living with the disease) of IPF was 495.5 cases per 100,000 Medicare beneficiaries.(A disease that is rare is defined as one in which fewer than 1 in 50,000 people have the disease, so that IPF is uncommon, but not rare.)   

Looking at deaths from IPF estimates predicted that 13,000 to 17,000 people would die from IPF in the United States in 2014 and between 28,000 and 65,000 death in Europe. To put this in perspective, roughly 40,000 people die from breast cancer each year in the United States, making IPF a significant cause of illness and death.

For unknown reasons, the mortality from IPF appears to be increasing worldwide.

Who Gets IPF? - Causes/Risk Factors

It’s unknown what exactly causes IPF, hence, the term “idiopathic” which translated simply means “we don’t know the cause.” That said, there are risk factors that may predispose people to the disease. Some of these include:

  • Age - IPF is usually diagnosed in middle-aged people and older.
  • Smoking - Roughly 60 percent of people who develop IPF have a history of smoking.
  • Viral infections such as Epstein-Barr virus (which causes infectious mononucleosis.)
  • Environmental and occupational exposures.
  • Gastroesophageal reflux disease (GERD) - The majority of people diagnosed with IPF have a history of GERD with heartburn.
  • Family history (genetic predisposition) - IPF does run in families and a few gene mutations appear to increase the risk.

There are several known causes of pulmonary fibrosis caused by things such as radiation and medications, but these by definition would not be classified under idiopathic pulmonary fibrosis.


Antoniou, K., Tomassetti, S., Tsitoura, E., and C. Vancheri. Idiopathic pulmonary fibrosis and lung cancer: a clinical and pathogenesis update. Current Opinions in Pulmonary Medicine. 2015 Sep 18. (Epub ahead of print).

de Boer, K., and J. Lee. Under-recognised comorbidities in idiopathic pulmonary fibrosis: a review. Respirology. 2015 Sep 13. (Epub ahead of print).

Esposito, D. et al. Idiopathic Pulmonary Fibrosis in US Automated Claims: Incidence, Prevalence and Algorithm Validation. American Journal of Respiratory and Critical Care Medicine. 2015 Aug 4. (Epub ahead of print)>

Ghebremariam, Y. et al. Pleiotropic effect of the proton pump inhibitor esomeprazole leading to suppression of lung inflammation and fibrosis. Journal of Translational Medicine. 2015. 13:249.

Hao, W., Marsh, C., and A. Friedman. A Mathematical Model of Idiopathic Pulmonary Fibrosis. PLos One. 2015 Sep 8. 10(9):e0135097.

Hutchinson, J., McKeever, T., Fogarty, A., Navaratnam, V., and R. Hubbard. Increasing global mortality from idiopathic pulmonary fibrois in the twenty-first century. Annals of the American Thoracic Society. 2014. 11(8):1176-85.

Idiopathic Pulmonary Fibrosis Clinical Research Network, Martinez, F., deAndrade, J., Anstrom, K., King, T., and G. Raghu. Randomized trial of acetylcysteine in idiopathic pulmonary fibrosis. New England Journal of Medicine. 2014. 370(22):2093-101.

Kim, H., Perlman, D., and R. Tomic. Natural history of idiopathic pulmonary fibrosis. Respiratory Medicine. 2015. 109(6):661-70.

Kistler, K., Nalysnyk, L., Rotella, P., and D. Esser. Lung transplantation in idiopathic pulmonary fibrosis: a systematic review of the literature. BMC Pulmonary Medicine. 2014. 14:139.

Oldham, J. et al. TOLLIP, MUC5B and the Response to N-acetylcystein Among Individuals with Idiopathic Pulmonary Fibrosis. American Journal of Respiratory and Critical Care Medicine. 2015 Sep 2. (Epub ahead of print).

O’Riordan, T., Smith, V., and G. Raghu. Development of Novel Agents for Idiopathic Pulmonary Fibrosis: progress in target selection and clinical trial design. Chest. 2015 May 8. (Epub ahead of print).

Raghu, G. et al. Diagnosis of idiopathic pulmonary fibrosis with high-resolution CT in patients with little or no radiological evidence of honeycombing: secondary analysis of a randomized, controlled trial. Lancet Respiratory Medicine. 2014. 2(4):277-84.

Raghu, G. et al. Idiopathic pulmonary fibrosis in US Medicare beneficiaries aged 65 years and older: incidence, prevalence, and survival, 2001-11. Lancet Respiratory Medicine. 2014. 2(7):566-72.

Richeldi, L. et al. Efficacy and safety of nintedanib in idiopathic pulmonary fibrosis. New England Journal of Medicine. 2014. 370(22):2071-82.

Spagnolo, P., Maher, T., and L. Richeldi. Idiopathic pulmonary fibrosis: Recent advances on pharmacological therapy. Pharmacology & Therapeutics. 2015. 152:18-27.

Continue Reading