Bone disease and cystic fibrosis

Osteopenia and osteoporosis are terms that mean bones are ‘thinner’ than they should be. A more scientific description is that the skeleton has a low bone mass, which means that the bones are more fragile and more likely to fracture.

Bone mineral density (BMD) is a measure of bone mineralisation. Bone mineralisation is the level of minerals contained in bone. These levels are an indicator of the bone mass and therefore how strong the bones are.

People with CF might experience early thinning of the bones. BMD is usually normal in children with CF with a healthy BMI and lung function. Even so, many people with CF fail to gain bone normally or experience premature bone loss when they are teenagers.

About one-third of adults with CF have low BMD, which may mean they are more likely to get bone fractures.

There are many reasons that people with CF might have low BMD, including:

• Poor overall health
• Poor nutrition
• Steroids
• Low physical activity
• Delayed puberty
• CF-related diabetes
• The CF gene

BMD measurements compare your bone density with the bone density expected for a young, healthy adult or a healthy adult of your own age, gender and ethnicity. BMD results can be reported as ‘Z-scores’ or ‘T-scores,’ but Z-scores are usually the most appropriate method in people with cystic fibrosis.

BMD is usually measured by ‘dual energy X-ray absorptiometry’ (DEXA) scans. DEXA scans are used to measure BMD in the lumbar spine (below the chest and above the pelvis), the top of the leg (hip), the wrist, and the whole body.

• Screening for low BMD at regular DEXA scans and chest X-rays.
• Monitoring and treating low vitamin D and calcium levels.
• Improving nutrition.
• Ensuring people with CF have access to a specialist dietitian.
• Preventing and treating lung infections.
• Encouraging weight-bearing physical activity.
• Getting recommendations for appropriate physical activities from a CF physiotherapist.
• Keeping glucocorticoid treatment (prednisolone and inhaled steroids) to a minimum.
• Looking for and treating delayed puberty and low blood levels of testosterone and oestrogen.
• Potentially avoiding contraceptive injections and progesterone-only contraception.
• Avoiding smoking and alcohol.

Bisphosphonates are drugs that reduce bone breakdown. Studies in the general population have shown these drugs to help with the treatment of postmenopausal osteoporosis, osteoporosis in men and glucocorticoid-induced osteoporosis. There is also increasing evidence that they may be effective in adults with cystic fibrosis.

Download our bone health factsheet for detailed information about bone health in cystic fibrosis

Five-to-ten percent of people with cystic fibrosis will develop joint pain or joint disease (arthropathy) such as arthritis, with the risk increasing with age. The most common form of joint pain in CF is an arthritis that affects large joints, such as the knees, ankles, wrists, elbows and shoulders.

Arthritis in CF tends to come and go, with no symptoms between attacks. Joint pain can flare up during infections and periods of ill health.

Find out more about our joint pain Strategic Research Centre.