High-dose vitamin D during acute exacerbations protects bone health
Increased dosage helps mitigate bone loss in cystic fibrosis patients: Study
Taking high-dose vitamin D supplements during acute lung infections may help to improve bone health for people with cystic fibrosis (CF).
“These findings suggest that use of high-dose vitamin D supplementation during an APE [acute pulmonary exacerbation] may mitigate the bone loss suffered by people with CF with each APE,” researchers wrote in the study, “Changes in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis,” which was published in Bone.
People with CF are at increased risk of infection and tend to have elevated levels of inflammation in their bodies. These factors can lead to problems with bone health such as weakened bones.
Acute pulmonary exacerbations, or APEs, are times when lung function suddenly worsens, usually due to an infection. Previous studies have established that, during an APE, markers of bone resorption — changes in bone structure that causes the bones to be weaker — are increased.
Scientists test if vitamin D during an APE could help limit bone problems
In this study, a team of U.S. scientists tested whether vitamin D supplements during an APE might help to limit bone problems. Vitamin D is a nutrient involved in many bodily processes; it helps to support bone health and also has anti-inflammatory properties.
“As inflammation mediates bone loss, it is possible that the anti-inflammatory effect of vitamin D may mitigate the bone loss associated with APEs in people with CF,” the researchers wrote, adding, “The objective of this study was to examine the impact of high dose vitamin D on changes in bone turnover markers in adults with CF admitted with an APE.”
This study was done as part of a broader clinical trial called DISC (NCT01426256) that tested the effects of vitamin D during an APE in people with CF. The trial was sponsored by Emory University and conducted in collaboration with the Cystic Fibrosis Foundation.
In the study, participants admitted to the hospital for an APE were given either a placebo, or a supplement containing a high dose (250,000 international units or IU) of vitamin D. Three months later, patients who received vitamin D were started on a lower dose (50,000 IU) every other week for the next nine months; those on a placebo also took the placebo every other week. For context, the recommended daily intake of vitamin D for adolescents and adults is about 600 international units, according to the National Institutes of Health.
The analysis included data on 45 people with CF: 22 given high-dose vitamin D and 23 given placebo. In both groups, the median age was in the early 30s, and just over half of participants were women. At baseline (prior to receiving supplements/placebo), patients in the placebo group had significantly higher vitamin D levels.
To assess bone health, the researchers looked at levels of two markers of bone resorption, CTX-1 and P1NP. These markers “are surrogates for changes in bone biology that ultimately lead to increased risk for fracture [broken bones],” the researchers said.
The markers were assessed during the APE and then again after the exacerbation had resolved.
High-dose vitamin D mitigates bone loss after APE
Results showed that, in patients given placebo, average levels of both bone resorption markers increased following the APE: by 0.025 nanograms (ng)/mL for CTX-1, and by 5.5 ng/mL for P1NP. By contrast, average levels of both markers decreased for patients given vitamin D, by 0.034 ng/mL for CTX-1 and 10.4 ng/mL for P1NP.
Median levels of both bone resorption markers decreased significantly for patients given vitamin D, whereas median levels did not change significantly after the APE in the placebo group.
“In this study, participants with CF had significant reductions in markers of bone resorption and formation after recovering from admission for APE when treated with high-dose vitamin D during the admission. In contrast, participants with CF had non-significant increases in markers of bone resorption and formation after recovering from admission for APE when treated with standard of care for APE,” the scientists concluded.
“These findings suggest that use of high-dose vitamin D supplementation during an APE may mitigate the bone loss suffered by people with CF with each APE,” they added.
The team noted that, while this study suggests vitamin D may help preserve bone health during CF exacerbations, further work is needed to clarify the exact biological mechanisms underlying this phenomenon. They also highlighted a need for further research into the optimal dosing of vitamin D for this purpose, as well as additional studies into how vitamin D may be used in combination with other CF treatments, particularly CFTR modulators.
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