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Cystic Fibrosis (CF)

A common hereditary disease in which exocrine (secretory) glands produce abnormally thick mucus. This mucus can cause problems in digestion, breathing, and body cooling. NIH - National Cancer Institute

Cystic Fibrosis

Cystic fibrosis (SIS-tik fi-BRO-sis), or CF, is an inherited disease of the secretory (see-KREH-tor-ee) glands. Secretory glands include glands that make mucus and sweat.

"Inherited" means the disease is passed from parents to children through genes. People who have CF inherit two faulty genes for the disease - one from each parent. The parents likely don't have the disease themselves.

CF mainly affects the lungs, pancreas, liver, intestines, sinuses, and sex organs.


Mucus is a substance made by tissues that line some organs and body cavities, such as the lungs and nose. Normally, mucus is a slippery, watery substance. It keeps the linings of certain organs moist and prevents them from drying out or getting infected.

If you have CF, your mucus becomes thick and sticky. It builds up in your lungs and blocks your airways. (Airways are tubes that carry air in and out of your lungs.)

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What works? Research summarized

Evidence reviews

[The effects of physical exercise on cystic fibrosis: a review of the literature]

Bibliographic details: Schaar B, Platen P.  [The effects of physical exercise on cystic fibrosis: a review of the literature]. [Literaturanalyse: sportliche Activitaten bei zystischer Fibrose.] Atemwegs und Lungenkrankheiten 2006; 32(9): 361-365

Enteral tube feeding for cystic fibrosis

Bibliographic details: Malt G.  Enteral tube feeding for cystic fibrosis. International Journal of Child and Adolescent Health 2011; 4(1): 111-112 Available from: https://www.novapublishers.com/catalog/product_info.php?products_id=21072

Low glycaemic index dietary interventions in youth with cystic fibrosis: a systematic review and discussion of the clinical implications

A systematic review was conducted to assess what is known about the effect of low glycaemic index (GI) diets on glycaemic control, weight and quality of life in youth with cystic fibrosis (CF). Eligibility criteria were systematic reviews, randomised and non-randomised trials of low GI dietary interventions in CF. Outcomes examined were glycaemic control, quality of life, anthropometry and respiratory function. Reference lists were manually searched and experts in the field were consulted. Four studies met the eligibility criteria; two were excluded because they did not include data on any of the outcomes. The remaining two were studies that examined GI secondary to any other intervention: one used GI as a factor in enteral feeds and the other incorporated low GI dietary education into its treatment methodology. There is insufficient evidence to recommend use of low GI diets in CF. Since there is evidence to support use of low GI diets in type 1, type 2 and gestational diabetes, low GI diets should be tested as an intervention for CF. The potential risks and benefits of a low GI diet in CF are discussed.

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Summaries for consumers

Human Growth Hormone for Children With Cystic Fibrosis: A Review of the Research for Parents and Caregivers

This guide is for anyone who takes care of a child or teen with cystic fibrosis (CF) and helps make decisions about treatment. You may have heard about using human growth hormone (HGH) for children with CF and want to know more about the research.

The use of regular vitamin A preparations for children and adults with cystic fibrosis

Cystic fibrosis can lead to certain vitamins, such as vitamin A, not being properly absorbed by the body. This can result in problems caused by vitamin deficiency. A lack of vitamin A (vitamin A deficiency) can cause specific problems such as eye and skin problems. It can also be associated with poorer general and respiratory health. Therefore people with cystic fibrosis are usually given regular vitamin A preparations from a very young age. However, too much vitamin A can also cause respiratory and bone problems. The review aimed to show whether giving vitamin A regularly to people with cystic fibrosis is beneficial or not. However, the authors did not find any relevant trials to include in the review. They are therefore unable to draw any conclusions regarding the routine administration of vitamin A supplements and recommend that until further evidence is available, local guidelines are followed regarding this practice.

Using tube feeding (via nose or stomach) in people with cystic fibrosis

Cystic fibrosis is an inherited condition which causes damage to the lungs and pancreas (an organ needed for the production of chemicals that help to digest food). People with cystic fibrosis often need a high energy diet in order to achieve a good nutritional status. To achieve this supplements are often given via a tube through the nose or stomach (enteral tube feeding). This type of feeding helps to improve weight gain, nutritional status, lung function and may improve quality of life. However, tube feeding is expensive and may impact on self‐esteem and body image. We have identified 28 trials in our searches, but none of these are randomised controlled trials showing the effects of enteral tube feeding. Hence no trials are included in the review. Ideally, more research is needed to compare tube feeding with oral supplements and with normal diet; also, trials should look at when tube feeding should be started for the best results. These trials may be difficult to do as it may be wrong not to provide extra calories in this way when needed.

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Terms to know

Body Fiber
In the body, fiber refers to tissue made of long threadlike cells, such as muscle fiber or nerve fiber.
Exocrine Glands
An organ that makes one or more substances, such as sweat, tears, saliva, or milk. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue. Fibrosis is similar to the process of scarring.
Inherited; having to do with information that is passed from parents to offspring through genes in sperm and egg cells.
A group of cells that secrete substances. Endocrine glands secrete hormones. Exocrine glands secrete salt, enzymes, and water.
A thick, slippery fluid made by the membranes that line certain organs of the body, including the nose, mouth, throat, and vagina.
Respiratory System
The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Also called respiratory tract.
To form and release a substance. In the body, cells secrete substances, such as sweat that cools the body or hormones that act in other parts of the body.
Fluid that exits the body through pores in the skin usually due to physical stress and/or high temperature for the purpose of regulating body temperature and removing certain compounds from the circulation.

More about Cystic Fibrosis

Photo of a child

Also called: Mucoviscidosis, Fibrocystic disease

Other terms to know: See all 9
Body Fiber, Exocrine Glands, Fibrosis

Keep up with systematic reviews on Cystic Fibrosis:


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