Takeaway
- Over a median of 3.3 years, monthly supplementation with 100,000 IU vitamin D3 did not increase the incidence of kidney stones or hypercalcaemia compared with placebo in adults aged 50-84 years.
Why this matters
- Findings confirm the safety of 100,000 IU monthly vitamin D supplementation, equivalent to 3300 IU/day, and within the 4000 IU/day dose recommended as the tolerable upper limit.
Study design
- Study used data from the ViDA (Vitamin D Assessment) trial to investigate whether 100,000 IU vitamin D3/monthly taken for ≥3 years increases the risk for kidney stones and hypercalcaemia (n=5056; aged 50-84 years).
- Funding: New Zealand Health Research Council and the Accident Compensation Corporation.
Key results
- During a median follow-up of 3.3 years, kidney stone event was recorded in 158 participants (vitamin D group, 76; placebo group, 82).
- The adjusted HR of time to first kidney stone event for vitamin D compared with placebo was 0.90 (95% CI, 0.66-1.23; P=.51).
- Urolithiasis was recorded in 18 participants (vitamin D group, 7; placebo group, 11).
- The HR to the first hospitalisation urolithiasis event was not increased in the vitamin group compared with placebo group (HR, 0.62; 95% CI, 0.24-1.26; P=.30).
- No participant in the vitamin D group of the randomly selected subgroup developed hypercalcaemia.
Limitations
- Study used questionnaire to collect self-reported kidney stone events which is not as accurate as ultrasound.
References
References
