Your body constantly renews your bone tissue in a process called bone turnover or bone remodeling. This process involves resorption (breaking down bone) and then reforming it.

In people with cystic fibrosis (CF), bone turnover is imbalanced in favor of resorption. This imbalance means that your body loses more bone minerals than it reforms. Over time, this can lead to less dense, weaker bones and a higher risk of fractures.

A 2023 research review shared that bone mineral loss occurs because CF-causing mutations in the CFTR gene also prevent the proper production of osteoblasts, cells that help form new bone. Other factors, like chronic inflammation and vitamin deficiencies due to malabsorption, may worsen the issue.

Imbalanced bone turnover may not cause immediately noticeable symptoms in people with CF, especially in the early years. However, in later teens and early adulthood, they may be at an increased risk of osteopenia and osteoporosis (porous bones).

Research used in a 2022 study suggested that as many as 70% of adults with CF have a lower-than-expected bone mineral density.

Osteopenia and osteoporosis may not necessarily cause symptoms, but a doctor might detect them through regular screening tests, such as a dual-energy X-ray (DEXA) scan.

One key way in which these conditions may show up is in the increased risk of fractures if you fall or experience an injury to your bones.

Vitamin deficiencies can contribute to reduced bone health in people with CF. But a 2019 research review shared that consuming enough of the following may help promote bone health:

Experts also suggest doing high impact, weight-bearing physical activity like jumping or skipping.

Bisphosphonates may be the first medication doctors prescribe to increase bone density in children or adults with CF. It’s important to take them on an empty stomach.

CFTR modulators are a relatively newer class of medications that may change CFTR function and reduce inflammation. However, the overall effect is still unclear, and more research is necessary.

Including regular bone density monitoring in your CF treatment plan is a good idea. The Cystic Fibrosis Foundation recommends having a DEXA scan by age 18 years and having one every 1 to 5 years.