D2d
Trial question
What is the role of vitamin D supplementation in adults at high risk for T2DM not selected for vitamin D insufficiency?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
45.0% female
55.0% male
N = 2423
2423 patients (1086 female, 1337 male).
Inclusion criteria: adults at high risk for T2DM not selected for vitamin D insufficiency.
Key exclusion criteria: any glycemic criterion in the diabetes range affecting the glycated hemoglobin level; use of diabetes or weight-loss medications; use of supplements containing vitamin D at a dose > 1,000 IU/day or calcium at a dose > 600 mg/day.
Interventions
N=1211 vitamin D supplementation (at a dose of 4,000 IU/day of vitamin D3 supplementation).
N=1212 placebo (matching placebo).
Primary outcome
Incidence of new-onset diabetes
9.39
10.66
10.7/100 py
8.0/100 py
5.3/100 py
2.7/100 py
0.0/100 py
Vitamin D
supplementation
Placebo
No significant
difference ↔
No significant difference in the incidence of new-onset diabetes (9.39 events /100 py vs. 10.66 events /100 py; HR 0.88, 95% CI 0.75 to 1.04).
Safety outcomes
No significant differences in hypercalcemia, fasting urine calcium/creatinine ratio > 0.375, low eGFR, nephrolithiasis.
Conclusion
In adults at high risk for T2DM not selected for vitamin D insufficiency, vitamin D supplementation was not superior to placebo with respect to the incidence of new-onset diabetes.
Reference
Anastassios G Pittas, Bess Dawson-Hughes, Patricia Sheehan et al. Vitamin D Supplementation and Prevention of Type 2 Diabetes. N Engl J Med. 2019 Aug 8;381(6):520-530.
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