We’ve heard a lot about vitamin D’s role in primary hyperparathyroidism lately.
Primary hyperparathyroidism (PHPT) is a disorder affecting the parathyroid glands caused by a benign tumor. It can cause some health issues including decreased vitamin D status, dangerously high calcium levels, and bone disorders.
Since PHPT can cause high calcium levels, doctors are often hesitant to prescribe vitamin D because they’re worried it might tip the calcium balance even higher.
So, researchers have long been interested if vitamin D is safe to take in PHPT. Just last month, a meta-analysis examining vitamin D supplementation, calcium levels and PTH was published, to see how safe vitamin D is in PHPT. Brant Cebulla discussed the paper at length. The researchers’ main findings were that vitamin D is safe in mild PHPT.
However, the meta-analysis only examined observational studies, and to date, observational studies were all we had.
Now, scientists in Denmark conducted the first double blind, randomized placebo controlled study examining the safety and efficacy of vitamin D supplementation for calcium regulation and bone metabolism in PHPT patients, thus shoring up this gap in research.
The researchers recruited 40 PHPT patients ages 29 to 77 for the study. All participants were eligible for surgery to remove the affected parathyroid gland, called a parathyroidectomy, which is often the only treatment for PHPT.
Twenty patients took 2,800 IU daily, while the control group took an identical placebo. All participants had a parathyroidectomy 6 months into the study and were examined 6 times before the surgery and 3 times post-surgery.
Was vitamin D safe? Did it help in calcium regulation? Here is what they found:
- During the first 6 months, the treatment group’s vitamin D status increased from 20 ng/ml to 38 ng/ml. The placebo group’s average levels decreased from 23 ng/ml to 20.8 ng/ml. There was no difference in serum calcium between the two groups. In all patients, calcium levels dropped significantly following surgery.
- In the vitamin D group, PTH levels decreased by 17% in comparison to the placebo group during the first half of the study. Furthermore, after surgery, PTH levels were significantly lower than the levels of participants taking a placebo (P=.039).
- Compared to the placebo group, the vitamin D group had a 22% decrease in CTx preoperatively. CTx is a marker used to assess bone turnover. This means that vitamin D supplementation was helpful in bone health, in essence. Additionally, the treatment group had an average increase in spine bone mineral density of 2.5% (P=.01) compared to the placebo group.
The researchers concluded,
“The study supports a more widely use of vitamin D supplementation in PHPT patients.”
This randomized controlled trial demonstrates that:
- Vitamin D is proven to be fairly safe in PHPT. There were no cases of severe hypercalcemia in the vitamin D group.
- Not only is vitamin D safe, but it lowers PTH and improves bone health markers and density.
Doctors treating patients with PHPT should move forward with a bit of caution, but also be reassured that for now, vitamin D appears safe in PHPT, and even helpful pre- and post-surgery.