What Are the Causes of Bone Disease in CF?

There are many reasons why people with cystic fibrosis get osteoporosis or osteopenia. It is important to remember that nutrition, lung disease and bone health are related. When people do not feel well, they eat less and they exercise less.

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Poor food digestion, called malabsorption, causes malnutrition. With malabsorption, the body may not get the vitamins and minerals it needs. This can be a problem because vitamin D, a fat-soluble vitamin, and calcium are vital to bone health. The right amount of pancreatic enzymes and food are necessary to optimize absorption and promote a good body weight and healthy bones. Low body weight can lead to low bone density and fractures.

Poor nutrition and lung disease can slow puberty, which can hinder bone growth. A lot of bone is made during the teen years. Because this is the bone you will have for the rest of your life, slowed puberty can lead to weaker bones. This sets the stage for future bone disease. If most of your calories (or energy) come from low-nutrient-density foods, such as potato chips, cookies, candy bars and sodas, you won't be getting the nutrition you need to build strong bones.

Prompt diagnosis and care for CF-related diabetes (CFRD) is vital for bone health. Diabetes treatment makes it possible for the body to use the vitamins and minerals in food for building and maintaining bones.

Lung Infections

Lung infections cause inflammation, which can interfere with the body's natural process of forming new bones to replace old or damaged bones. This interference can lead to increased bone loss. Early treatment of exacerbations may lessen bone loss.

Lack of Exercise, Especially Weight-bearing Exercise

When people are sick and inactive, muscles and bones weaken. Activity helps bones get strong and stay strong.

Did you know? Caffeine, alcohol, tobacco and some medicines can make you prone to bone disease.


Ask your CF care team how your medicines or supplements affect bone health. The following medications and supplements may affect bone health:

  1. Steroids can help lungs but hurt bones. Long-term steroid use can make bones thin and weak. Your CF care team should monitor the use of them.
  2. Medroxyprogesterone acetate (Depo-Provera®) is birth control medicine. It may raise your risk of bone disease. It should be avoided if possible.
  3. Megestrol acetate (Megace®) is used to increase appetite. It may affect testosterone levels and raise the risk of bone loss. If you are taking megestrol acetate, your CF care team should monitor its use. 
  4. Medicines that suppress the immune system that are used after transplants raise the risk of osteoporosis.
  5. Aluminum-containing antacids can block calcium absorption. Avoid them. Some antacids provide calcium. Ask your CF care team or dietitian which antacids to take.
  6. Herbal medicines and “natural supplements” can block the absorption of nutrients. Talk with your CF care team or dietitian before using them.
  7. An iron supplement, which some people with CF need, should not be taken at the same time as a calcium supplement because it can affect the absorption of calcium.

Other Causes and Risk Factors

  • Tobacco, alcohol, and caffeine use
  • Chronic bone and joint swelling
  • CF-related diabetes
  • Organ transplant
  • Low sexual hormones
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