Paper
Safety of High-Dose Vitamin D Supplementation: Secondary Analysis of a Randomized Controlled Trial.
Published Nov 20, 2019 · E. Billington, L. Burt, M. Rose
The Journal of clinical endocrinology and metabolism
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Abstract
CONTEXT Over 3% of adults report vitamin D intakes ≥4000 IU/day, but the safety of this practice is unknown. OBJECTIVE To establish whether vitamin D doses up to 10000 IU/day are safe and well-tolerated. DESIGN The Calgary Vitamin D Study was a three-year double-blind RCT. SETTING Single-centre study at the University of Calgary, Canada. PARTICIPANTS Healthy adults (n=373) aged 55-70 with serum 25-hydroxyvitamin D 30-125 nmol/L. INTERVENTIONS Participants were randomized 1:1:1 to vitamin D3 400, 40000 or 10000 IU/day. Calcium supplementation was initiated if dietary calcium intake was <1200mg/day. MAIN OUTCOME MEASURES In these pre-specified secondary analyses, changes in serum 25-hydroxyvitamin D, calcium, creatinine, 24-hour urine calcium excretion, and incidence of adverse events were assessed. Between-group differences in adverse events were examined using incident rate differences and logistic regression. RESULTS Of 373 participants (400:124, 4000:125, 10000:124), 49% were male, mean (SD) age was 64 (4) years, and 25-hydroxyvitamin D 78.0 (19.5) nmol/L. Serum calcium, creatinine, and 24-hour urine calcium excretion did not differ between treatments. Mild hypercalcemia (2.56-2.64 mmol/L) occurred in 15 (4%) participants (400:0%, 4000:3%, 10000:9%, p=0.002); all cases resolved on repeat testing. Hypercalciuria occurred in 87 (23%) participants (400:17%, 4000:22%, 10000:31%, p=0.011). Clinical adverse events were experienced by 365 (97.9%) participants and were balanced across treatment arms. CONCLUSIONS The safety profile of vitamin D supplementation is similar for doses of 400, 4000 and 10000 IU/day. Hypercalciuria was common and occurred more frequently with higher doses. Hypercalcemia occurred more frequently with higher doses but was rare, mild, and transient.
RCT
Large Human Trial
Rigorous JournalHigh-dose vitamin D supplementation (up to 10,000 IU/day) is generally safe, with mild and transient hypercalcemia occurring more frequently at higher doses.
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