Kinetics and concentrations of circulating 25-hydroxyvitamin D using different vitamin D repletion regimens.

All three vitamin D dosing regimens produced statistically significant increases in 25(OH)D levels from baseline to 4 weeks and again from 4 to 8 weeks, after which levels plateaued.

• Levels plateaued 'at the mid-40s ng/mL' following the initial rise through week 8
• The mean baseline 25(OH)D level across all 60 participants was 19.4 ng/mL
• Study population had average age 44.8 years and was 80% female
• All three arms showed statistically significant increases at both the baseline-to-week-4 and week-4-to-week-8 intervals

Group A (7000 IU daily) had a slightly but significantly higher mean 25(OH)D level than Group B (50,000 IU weekly) at baseline and at week 36.

• Baseline levels: Group A 21.0 ng/mL vs. Group B 16.9 ng/mL (p = 0.03)
• Week 36 levels: Group A 47.7 ng/mL vs. Group B 40.2 ng/mL (p = 0.007)
• No significant differences between any groups were observed at any other time points
• These differences occurred despite different dosing frequencies and amounts

All three vitamin D repletion regimens achieved vitamin D sufficiency within 12 weeks.

• Regimen A: 7000 IU daily for 12 weeks followed by 3500 IU daily for 24 weeks
• Regimen B: 50,000 IU weekly for 12 weeks followed by 25,000 IU weekly for 24 weeks
• Regimen C: 100,000 IU every other week for 12 weeks followed by 50,000 IU every other week for 24 weeks
• After 36 weeks, all subjects received the same cumulative amount of vitamin D
• Vitamin D was administered via oral drops

The study population consisted of 60 community-dwelling adults in Yerevan, Armenia, who were deficient in vitamin D at baseline.

• Mean baseline 25(OH)D level was 19.4 ng/mL, indicating deficiency
• Average age was 44.8 years; 80% were female
• Participants were randomized to one of three treatment arms (n=60 total)
• 25(OH)D levels were measured at baseline and at weeks 4, 8, 12, 24, and 36
• The study was conducted in Armenia, where vitamin D repletion guidelines had not previously been tested

Vitamin D replacement regimens in Armenia had not previously been tested, motivating this investigation of three administration strategies.

• Vitamin D deficiency is described as 'common throughout the world'
• Guidelines for vitamin D replacement exist but had not been tested in Armenia specifically
• The study aimed to investigate low dose-high frequency, medium dose-medium frequency, and high dose-low frequency regimens
• The study was conducted in community-dwelling adults in Yerevan, Armenia