Causes and Risk Factors of Pulmonary Fibrosis

Pulmonary fibrosis is a rare, incurable lung disease in which the tissue of the lung becomes thickened and scarred. The scarred tissue is not able to function like normal lung tissue and leads to progressive loss of function of the lungs.

Over time, as oxygen enters the lungs, the scarred tissue is unable to allow the oxygen to enter the bloodstream. This eventually leads to respiratory failure. An estimated 50,000 people are diagnosed with pulmonary fibrosis every year.

In this article, we'll explore the causes and risk factors for developing pulmonary fibrosis.

Common Causes 

Idiopathic Pulmonary Fibrosis

About half of the people diagnosed with pulmonary fibrosis have idiopathic pulmonary fibrosis, meaning there is no known cause. The air sacs in the lungs become stiff and scarred over time, for no specific reason. The course of the disease can vary among individuals, with some having stable disease for several years while others progress quickly.

Familial Pulmonary Fibrosis

Familial pulmonary fibrosis is diagnosed when pulmonary fibrosis occurs in at least two related family members. There are a number of genetic mutations that are thought to potentially be related to the cause of familial pulmonary fibrosis, but these cases can still be considered idiopathic as well.

Causes From Other Disorders

There can be other health issues that lead to the development of pulmonary fibrosis. Having a history of an autoimmune disorder (such as lupus or rheumatoid arthritis) can increase the risk of developing pulmonary fibrosis. Other illnesses, such as gastroesophageal reflux disease, sleep apnea, or pulmonary hypertension, can increase the risk.

Genetics

Although research is still ongoing, there have been some genes that have been associated with the development of pulmonary fibrosis. The genes TERC and TERT have been found to be present in about 15% of those with familial pulmonary fibrosis. Other genetic mutations that have been found to be associated with the development of pulmonary fibrosis are more rare, occurring in less than 1% and up to 5% of cases.

It has been found that pulmonary fibrosis can develop when only one copy of the faulty gene is inherited from a parent. However, having this faulty gene does not guarantee that someone will develop pulmonary fibrosis. It is currently unknown why some people with the gene get it while others with the gene do not.

Risk Factors 

Although many times there is no known specific cause of pulmonary fibrosis, there are factors that can increase someone’s risk of developing pulmonary fibrosis. 

Smoking

A history of smoking cigarettes or other tobacco products increases the risk of developing pulmonary fibrosis.

Workplace Exposure

People who have worked in certain industries, such as in construction, factory work, or farming, may have had exposure to certain chemicals or other compounds that increase the risk. These chemicals and compounds can include:

• Asbestos
• Mold
• Heavy amounts of dust
• Wood dust
• Silica
• Animal feed
• Bird droppings or livestock waste
• Coal
  

Working in well-ventilated areas or wearing properly fitting respiratory masks can help decrease the number of particles inhaled. 

Medical Risk Factors

In addition to the workplace exposures outlined above, there are other risk factors associated with the development of pulmonary fibrosis:

• Medications: Certain medications can increase risk, including amiodarone, some chemotherapy medications, and methotrexate.
• Radiation: Previous exposure to radiation can increase the risk.

A Word From Verywell 

While in many cases there is no known cause of pulmonary fibrosis, certain factors are known to increase your risk of developing this condition. So it can be important to avoid factors that are within your control, such as stopping smoking and reducing your exposure to certain industrial chemicals. If you have a family history of pulmonary fibrosis, it can be especially important to stay as healthy as possible. If you have concerns about your risk, talk with your healthcare provider about measures you can take to reduce it.