Researchers studied 58 people with cystic fibrosis who received ultra-high doses of vitamin D (called ‘stoss dosing’) to boost their vitamin D levels. This approach worked well even for patients who often forgot to take their daily vitamin D pills. After receiving the high dose, vitamin D levels in the blood increased from an average of 20.1 to 27.9 ng/mL. Most importantly, 80% of patients who admitted they often skipped their regular vitamins still reached healthy vitamin D levels after the treatment. This suggests that occasional high-dose vitamin D could be a helpful backup plan for people with cystic fibrosis who struggle with daily supplements.

The Quick Take

  • What they studied: Whether giving very large doses of vitamin D all at once could help people with cystic fibrosis who struggle to take daily vitamin pills
  • Who participated: 58 children and adults with cystic fibrosis who were treated at University of Iowa hospitals between 2017 and 2021
  • Key finding: Vitamin D blood levels increased by about 40% on average, and 80% of patients who often skipped daily vitamins still reached healthy levels
  • What it means for you: If you have cystic fibrosis and struggle with daily vitamins, ask your doctor about high-dose vitamin D treatments as a backup option

The Research Details

This was a retrospective study, meaning researchers looked back at medical records of patients who had already received the high-dose vitamin D treatment. They tracked vitamin D blood levels before and after treatment to see how well it worked. The researchers focused on patients who received their first high-dose treatment between 2017 and 2021 at two cystic fibrosis centers in Iowa. They measured vitamin D levels in the blood using a test called serum 25(OH)D, which shows how much vitamin D is stored in your body. The high doses were given according to a specific medical protocol already in use at these centers.

This approach helps us understand how well high-dose vitamin D works in real-world medical practice, not just in controlled research settings. Since the researchers looked at patients who were already receiving this treatment as part of their regular care, the results may better reflect what happens when doctors actually use this approach with their patients.

The study included a reasonable number of patients from two different medical centers, which strengthens the findings. However, since researchers looked backward at medical records rather than following patients forward in time, they couldn’t control all the factors that might affect results. The follow-up blood tests were done an average of 116 days after treatment, giving enough time to see the effects.

What the Results Show

The main finding was that high-dose vitamin D treatment significantly improved vitamin D levels in people with cystic fibrosis. Before treatment, the average vitamin D level was 20.1 ng/mL, which is considered insufficient. After the high-dose treatment, levels rose to an average of 27.9 ng/mL, representing about a 40% increase. This improvement was measured about four months after receiving the treatment, showing the effects lasted for a reasonable period. The treatment appeared to work regardless of whether patients were good at taking their daily vitamin supplements or not.

The most encouraging secondary finding was how well the treatment worked for patients who admitted they often forgot or skipped their daily vitamin D pills. Among the 20 patients who reported poor adherence to their regular vitamin regimen, 16 (80%) achieved vitamin D levels of at least 30 ng/mL after the high-dose treatment. This suggests that stoss dosing could serve as an effective safety net for patients who struggle with daily medication routines.

This study adds to existing knowledge about vitamin D supplementation in cystic fibrosis by specifically examining how high-dose treatments work in patients with variable adherence to daily supplements. Previous research has established that people with cystic fibrosis commonly have vitamin D deficiency, but this study provides practical evidence that intermittent high-dose treatments can be effective even when daily supplements aren’t taken consistently.

Since this was a retrospective study, researchers couldn’t control all factors that might have influenced the results. The study didn’t compare high-dose treatment directly to other approaches, so we can’t say it’s better than alternatives. The follow-up period varied among patients, and the study didn’t track long-term effects beyond a few months. Additionally, adherence to daily vitamins was self-reported, which may not always be accurate.

The Bottom Line

If you have cystic fibrosis and struggle to take daily vitamin D supplements consistently, discuss high-dose vitamin D treatments with your healthcare team. This approach appears to be effective at raising vitamin D levels even when daily supplements are missed frequently. However, this should be done under medical supervision as part of a comprehensive cystic fibrosis care plan.

This research is most relevant for people with cystic fibrosis who have difficulty maintaining consistent daily vitamin D supplementation. Healthcare providers treating cystic fibrosis patients may also find this useful for developing treatment strategies. People without cystic fibrosis should not assume these findings apply to them.

Based on this study, improvements in vitamin D levels can be seen within about four months of receiving high-dose treatment. However, the timing of follow-up blood tests varied, so some patients may see changes sooner or later.

Want to Apply This Research?

Use the Gram app to:

  • Track your daily vitamin D supplement intake and note any missed doses, along with periodic vitamin D blood test results from your doctor
  • Set up medication reminders for daily vitamin D supplements, but don’t panic if you miss doses - discuss backup high-dose options with your healthcare provider
  • Monitor adherence to daily supplements over monthly periods and schedule regular vitamin D blood tests as recommended by your cystic fibrosis care team

This information is for educational purposes only and should not replace professional medical advice. People with cystic fibrosis should work closely with their healthcare team to develop appropriate vitamin D supplementation strategies. High-dose vitamin D treatments should only be administered under medical supervision.