A study has come out recently; a study that I am sure you are familiar with (received plenty of media attention) and a study type that is considered the gold standard in medicine (randomized controlled trial).
Lehouck A et al. High Doses of Vitamin D to Reduce Exacerbations in Chronic Obstructive Pulmonary Disease (COPD): A Randomized Trial, Annals of Internal Medicine, 2012 Jan 17; 156(2): 105-14.
Let’s review this study by the core areas: who (population), how (intervention), and what (conclusions/findings):
- Who: Lehouck et al looked at patients (182) with moderate to very severe COPD with a history of recent exacerbations (flare-ups) who were undergoing treatment at one hospital in Belgium (14% on steroid pills, 82% on inhalation drug therapy, and 22% on 800 IU D). 17.6% were current smokers. Mean 25(OH)D levels were 20 ng/mL. Basically, this was a very sick group getting lots of medical care and who were D deficient on average. Fifteen patients (8%) died during the year-long treatment.
- How: This was a double-blind, randomized, and placebo-controlled study. Patients were randomly divided into two groups: placebo and D (100,000 IU/ month (equivalent to 3,200 IU/day)
- What: The abstract concluded: “High-dose vitamin D supplementation in a sample of patients with COPD did not reduce the incidence of exacerbations (JL note: a flare-up). In participants with severe vitamin D deficiency at baseline, supplementation may reduce exacerbations.”
The devil is always in the details; let’s dig into those findings.
First: seriously sick elderly folks undergoing medical treatment overall didn’t get better by any measurement. I’m not surprised. These are folks with damaged lungs at the end of their lives, getting lots of drugs, and were recruited when they were having problems. Some even continued to smoke.
Second: Seriously D deficient folks (<10 ng/mL), however, reduced their rate of flare-ups/year by 43% with D. So, D does have an effect, but it is basically a step function (more deficient get better than less deficient).
Third: The 3,200 IU/day D dose was effective at raising mean 25(OH)D levels to a stable 50-52 ng/ml. Note that it took 4 months to do so (remember D substrate starvation, basically a backlog of unmet D needs).
In my opinion, the severe D deficient group is too small to generalize conclusively.
Many worry about D toxicity. The 100,000 IU D dose resulted in no observed symptomatic calcium-related toxicity. There were 4 cases of small, temporary asymptomatic hypercalcemia peaks at 4 months that resolved quickly. There were zero cases at 8 and 12 months. I see this as the body adapting to new D levels, which increases calcium uptake, but the body always seeks to re-balance itself.
So what can we conclude?
- D dosing is safe at 100,000 IU per month and effective in raising blood levels.
- D may help severely D deficient patients(<10 ng/mL) with COPD.
- Most COPD patients are deficient in D (mean 25(OH)D = 20 ng/mL).
- D probably does not fix already seriously damaged patients. D’s effects may be masked by smoking and strong drugs as well as subgroup effects
In my opinion, it is still an open question if D might help prevent COPD before the damage is done (although I suggest people be careful in assuming D will protect them from smoking’s effects. I see this a lot: “Woohoo. I had heart surgery so I can keep on drinking, smoking, and eating Twinkies!”). Be careful reading headlines, press releases, and abstracts. The devil is always in the details.