Endocrine Abstracts

Introduction: Oral supplements are important to prevent and treat vitamin D deficiency. Membrane transporters could be involved in its absorption. As vitamin D is structurally similar to cholesterol, it is possible that they share absorption mechanisms. Ezetimibe decreases cholesterol absorption, through inhibition of NPC1L1 transporter. It has been shown in vitro and in rodents that ezetimibe decreases vitamin D absorption, so the aim of this study was to evaluate the effect of ezetimibe on 25-hydroxyvitamin D [25(OH)D] levels in response to a single oral dose of vitamin D, in young persons.

Methods: This randomised, double-blind, placebo-controlled trial (ClinicalTrials.gov NCT02234544) was developed in a South Brazilian University Hospital. Fifty-one medical students were randomised to ezetimibe 10 mg/day or placebo for 5 days. On the 5th and 19th days, blood samples for 25(OH)D, PTH, calcium, and albumin were collected after overnight fast. On the 5th day, all participants received a single oral 50 000 IU cholecalciferol dose during a 15 g fat meal. 25(OH)D was measured by the immunoassay Diasorin Liaison. Measurements were compared in a general linear model adjusted for multiple comparisons by the Bonferroni test.

Results: At baseline, 25(OH)D was <30 and <20 ng/ml, respectively, in all and 82.3% of the participants. Fourteen days after a single 50 000 IU oral dose of cholecalciferol, the mean (S.D.) change in 25(OH)D was of 8.75 (3.74) ng/ml in the ezetimibe group, vs 10.02 (3.84) ng/ml in the placebo group, after adjustment to baseline 25(OH)D levels and BMI (P=0.26). Mean 25(OH)D, PTH, calcium and albumin remained similar in both groups.

Conclusions: Ezetimibe had no effect on the mean change in serum 25(OH)D after a single oral dose of cholecalciferol.

Disclosure: University hospital research incentive fund (FIPE/HCPA project 14-0378).