Vitamin D Supplement OK in Hyperparathyroidism Patients

Vitamin D treatment can safely be used in patients with primary hyperparathyroidism who also have a vitamin D deficiency, according to a new study presented recently at The Endocrine Society's 94th Annual Meeting in Houston.¹

Concerns about raising calcium levels in patients with primary hyperparathyroidism have given physicians pause when they consider recommending vitamin D supplementation. Study authors suggest that the benefits of vitamin D, which helps the body absorb calcium and is vital for bone health, may merit the use of a supplement, if patients are carefully monitored.

"These patients need close monitoring every three to four months during vitamin D replacement therapy," said Dima Abdelmannan, MD, an assistant professor at Case Western Reserve University in Cleveland and an endocrinologist at the Cleveland VAMC.

Abdelmannan, who presented the research findings, said doctors should measure blood levels of calcium and parathyroid hormone along with vitamin D levels throughout treatment.

"Measuring vitamin D levels alone may not be helpful in the management of vitamin D deficiency in patients with primary hyperparathyroidism," she said. "The commercially available blood test for vitamin D level — the 25-hydroxyvitamin D — has limitations."

For the study, researchers reviewed the medical records of 32 patients at the VAMC who had both primary hyperparathyroidism and vitamin D deficiency. All 10 women and 22 men had hypercalcemia, or high calcium in the blood, defined as a level greater than 10.1 milligrams per deciliter (mg/dL), and had vitamin D levels below the cutoff for normal of 30 nanograms per deciliter (ng/dL) on the 25-hydroxyvitamin D test for vitamin D.

Vitamin D2 (ergocalciferol) or vitamin D3 (cholecalciferol) was administered at an average daily dose of 3,630 IU. Most patients had their parathyroid hormone, calcium and vitamin D levels checked every three months for a year after commencing treatment.

Vitamin D levels returned to normal with treatment and remained normal at all intervals, Abdelmannan said, yet the average calcium blood level "remained virtually unchanged" from the pretreatment level of 10.7 mg/dL. The calcium level was 10.8 mg/dL at three months after treatment, 10.6 at six months and 10.7 at 12 months, the authors reported.

Despite the lack of increase in calcium levels, parathyroid hormone levels decreased from an average of 124 picograms per deciliter (pg/dL) before treatment to103 pg/dL one year after treatment. High calcium levels in hyperparathyroidism can cause bone aches, fatigue and kidney stones.

In its 2011 guideline on treating vitamin D deficiency, The Endocrine Society recommends that patients with primary hyperparathyroidism and vitamin D deficiency receive vitamin D treatment as needed and that serum (blood) calcium levels should be monitored.

1. Abdelmannan, D; Leciejewski, K, Ajlouni, H, et al. “Vitamin D Supplementation in Vitamin D Deficient Patients with Primary Hyperparathyroidism: Impact on Calcium and Parathyroid Hormone Levels.” The Endocrine Society, Houston June 23-26

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