Cystic fibrosis Patient friendly summary

Cystic fibrosis is a genetic disorder that primarily affects the lungs and digestive system.

Cystic fibrosis is a respiratory disease that causes a thick, sticky mucus to form in the lungs, pancreas, and other organs. In the lungs the mucus blocks the airways, causing breathing difficulties and lung damage. It also clogs the pathways leading to the digestive system, interfering with proper digestion.

The average life expectancy for those with cystic fibrosis is 37 years. Often, death is due to respiratory failure following a chronic pulmonary (lung) infection.

Risk factors

Cystic fibrosis is a genetic disorder that affects 1 in every 3000 births.

Sunlight exposure and cystic fibrosis risk  

At this time, there is no evidence that sunlight exposure lowers risk of cystic fibrosis.

Vitamin D and cystic fibrosis

Vitamin D levels

Proper sunlight exposure is the best option for obtaining vitamin D for those with cystic fibrosis.

People with cystic fibrosis generally have low vitamin D levels, the primary consequences of which are reduced bone mass and lung function and increased risk of respiratory infection. Due to impaired absorption of nutrients in the digestive tract, cystic fibrosis patients who wish to keep their vitamin D levels up will require proper sun exposure or use of a tanning bed.

Vitamin D's benefits

Vitamin D helps people with cystic fibrosis in several ways:

  • Improves calcium absorption and metabolism, leading to improved bone health
  • Preserves lung function, in part by lowering inflammation
  • Reduces risk of respiratory infections
  • Strengthens the immune system by inducing cathelicidin and defensins, proteins with antibiotic properties


To date, there is no evidence that supplemental vitamin D aids in the prevention of cystic fibrosis.


Eight different trials had different results when studying vitamin D's effect on cystic fibrosis patients. However, the studies used different dosages and forms of vitamin D, which may explain the varying results.

Find out more...

We will be adding a detailed evidence summary on this topic in the near future. Please check back soon to find out more.

Page last edited: 25 June 2011