Efficacy of various prescribed vitamin D supplementation regimens on 25-hydroxyvitamin D serum levels in long-term care

Ronna N. Robbins, Monica Serra, Nalini Ranjit, Deanna M. Hoelscher, Sara J. Sweitzer, Margaret E. Briley

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Objective: The aims of this study were to examine the efficacy among various vitamin D supplementation regimens on serum 25(OH)D concentrations and determine the minimal dose rate required to achieve sufficient serum concentrations (≥75 nmol/L) among older adults in long-term care (LTC). Design: A one-year medical history was abstracted from medical records, and a one-time blood draw to measure serum 25(OH)D concentrations was obtained. Individuals were stratified into vitamin D supplemented and non-supplemented groups. The supplemented group was further categorized into four treatment forms: single ingredient vitamin D2or3, multivitamin, calcium with vitamin D, or combination of the three, and by daily prescribed doses: 0-399, 400-799, 800-1999, 2000-3999, and >4000 IU/day. Setting: Five LTC communities in Austin, Texas. Participants: 173 older (≥65 years) adults. Results: Of the participants, 62% received a vitamin D supplement and 55% had insufficient (≤75 nmol/L) 25(OH)D serum concentrations. Individuals receiving single ingredient vitamin D2or3 supplementation received the highest daily vitamin D mean dose (2900 IU/d), while combination of forms was the most frequent treatment (44%) with the highest mean serum concentration (108 nmol/L). All supplementation doses were successful at reaching sufficient serum concentrations, except those <800 IU/d. Using a prediction model, it was observed that one IU/d of vitamin D supplementation resulted in a 0.008 nmol/L increase in serum 25(OH)D concentrations. Conclusion: Based on the predictive equation, results suggest that supplementation of 1500 IU/d of vitamin D2or3 or combination of vitamin D is most likely to achieve sufficient serum 25(OH)D concentrations in older adults in LTC.

Original languageEnglish (US)
JournalPublic Health Nutrition
StateAccepted/In press - 2021


  • 25-hydroxyvitamin D
  • Long-term care
  • Older adults
  • Skilled-nursing
  • Supplementation
  • Vitamin D

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health


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