Abstract

Background: Primary hyperparathyroidism (PHPT) and vitamin D insufficiency are two very frequent conditions. In cases where the combination of both vitamin D insufficiency and PHPT is diagnosed, vitamin D repletion is an option. However, only limited evidence exists for this treatment. Objective: The aim of this review is to describe different aspects of concomitant vitamin D insufficiency and PHPT and in this setting to evaluate existing evidence on safety and possible outcome of vitamin D treatment. Methods: Background literature was found based on a search in pubmed.com and scirus.com. Results: Multiple association studies support the hypothesis that the clinical presentation of PHPT is more severe in patients with vitamin D insufficiency. Treatment with vitamin D in PHPT may decrease PTH levels and bone turnover and potentially increase bone mass in various compartments. However, some patients experience increasing plasma or urine levels of calcium, triggering either vitamin D withdrawal or surgery. Conclusion: Measurement of vitamin D in PHPT is important to fully assess the disorder. The causality of the frequent coexistence of vitamin D insufficiency and PHPT is not fully understood. Vitamin D treatment is recommended and may decrease PTH levels in PHPT. However, there is no randomized controlled trial to prove any beneficial effect. For safety reasons, it is recommended to monitor plasma and urinary calcium during treatment. Furthermore, the effect of vitamin D repletion on other outcomes like quality of life, muscle function and CNS symptoms should be assessed.

Keywords: Primary hyperparathyroidism, review, vitamin D insufficiency, vitamin D treatment, Klotho-FGFR1c, 1-alphahydroxylase (CYB 27B1)