Individual participant data (IPD)-level meta-analysis of randomised controlled trials with vitamin D-fortified foods to estimate Dietary Reference Values for vitamin D

Research output: Contribution to journalArticle


Context and purpose: Individual participant data-level meta-regression (IPD) analysis is superior to meta-regression based on aggregate data in determining Dietary Reference Values (DRV) for vitamin D. Using data from randomized controlled trials (RCTs) with vitamin D3-fortified foods, we undertook an IPD analysis of the response of winter serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among children and adults and derived DRV for vitamin D. Methods: IPD analysis using data from 1429 participants (ages 2–89 years) in 11 RCTs with vitamin D-fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D DRV estimates across a range of serum 25(OH)D thresholds using unadjusted and adjusted models. Results: Our IPD-derived estimates of vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25 and ≥ 30 nmol/L are 6 and 12 µg/day, respectively (unadjusted model). The intake estimates to maintain 90%, 95% and 97.5% of concentrations ≥ 50 nmol/L are 33.4, 57.5 and 92.3 µg/day, respectively (unadjusted) and 17.0, 28.1 and 43.6 µg/day, respectively (adjusted for mean values for baseline serum 25(OH)D, age and BMI). Conclusions: IPD-derived vitamin D intakes required to maintain 90%, 95% and 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L are much higher than those derived from standard meta-regression based on aggregate data, due to the inability of the latter to capture between person-variability. Our IPD provides further evidence that using food-based approaches to achieve an intake of 12 µg/day could prevent vitamin D deficiency (i.e., serum 25(OH)D < 30 nmol/L) in the general population.


  • Kevin D. Cashman
  • Mairead E. Kiely
  • Rikke Andersen
  • Ida M. Grønborg
  • Katja H. Madsen
  • Janna Nissen
  • Inge Tetens
  • Laura Tripkovic
  • Susan A. Lanham-New
  • Laura Toxqui
  • M. Pilar Vaquero
  • Ulrike Trautvetter
  • Gerhard Jahreis
  • Vikram V. Mistry
  • Bonny L. Specker
  • Jürgen Hower
  • Anette Knoll
  • Dennis Wagner
  • Reinhold Vieth
  • Inger Öhlund
  • And 4 others
  • Pia Karlsland Åkeson
  • Neil R. Brett
  • Hope A. Weiler
  • Christian Ritz
External organisations
  • University College Cork
  • Technical University of Denmark
  • University of Copenhagen
  • University of Surrey
  • CSIC Institute of Food Science, Technology and Nutrition (ICTAN)
  • Friedrich Schiller University Jena
  • South Dakota State University
  • University of Toronto
  • Mount Sinai Hospital of University of Toronto
  • Umeå University
  • McGill University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Nutrition and Dietetics


  • Dietary reference values, Individual participant data-level meta-regression analyses, Recommended dietary allowance, Vitamin D recommendations, Vitamin D-fortified foods
Original languageEnglish
JournalEuropean Journal of Nutrition
Publication statusE-pub ahead of print - 2020
Publication categoryResearch