Effect of Vitamin D replacement on indexes of insulin resistance in overweight elderly individuals: A randomized controlled trial

Ghada El Hajj Fuleihan, Rafic Baddoura, Robert H. Habib, Georges Halaby, Asma Arabi, Maya Rahme, Ravinder J. Singh, Moustapha Kassem, Ziyad Mahfoud, Maha Hoteit, Rose T. Daher, Mohamed Faisal Kassir

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23 Scopus citations

Abstract

It is unclear whether and at what dose vitamin D supplementation affects insulin resistance (IR). Objective: We sought to investigate whether vitamin D at doses higher than currently recommended decreases indexes of IR in an ambulatory population of overweight elderly subjects. Design: This double-blind, randomized, controlled multicenter trial enrolled 257 elderly overweight individuals aged ≥ 65 y with baseline 25-hydroxyvitamin D [25(OH)D] concentrations between 10 and 30 ng/mL. All subjects received 1000 mg calcium citrate/d, with vitamin D administered weekly at an equivalent dose of 600 or 3750 IU/d. The homeostasis model assessment (HOMA) of IR index at 1 y was the primary outcome.We also assessed the McAuley index. Results: In total, 222 subjects (55% women) with a mean ± SD age and body mass index (BMI; in kg/m2) of 71 ± 4 y and 30 ± 4, respectively, completed the study. Subjects' baseline characteristics, including IR indexes, were similar across groups: 69% had prediabetes, 54% had hypertension (47% were taking antihypertensive medications), and 60% had hyperlipidemia, nearly half of whom were receiving lipidlowering drugs. At 1 y, mean ± SD serum 25(OH)D increased from 20 ± 7 to 26 ± 7 ng/mL in the low-dose arm (P <0.0001) and from 21 ± 8 to 36 ± 10 ng/mL in the high-dose arm (P > 0.001). Median HOMA-IR indexes did not change compared with baseline concentrations and were similar in the high-[2.2 (IQR: 1.5, 2.9)] and low-dose [2.3 (IQR: 1.6, 3.3] treatment groups. Adjusted analyses showed that HOMA-IR was predicted by the baseline HOMA index and BMI but not by vitamin D dose, baseline serum 25(OH)D, or change in 25(OH)D. Conclusion: Vitamin D3 at 3750 IU/d did not improve HOMA-IR compared with the Institute of Medicine Recommended Dietary Allowance of 600 IU/d in elderly overweight individuals.

Original languageEnglish (US)
Pages (from-to)315-323
Number of pages9
JournalAmerican Journal of Clinical Nutrition
Volume104
Issue number2
DOIs
StatePublished - Aug 1 2016

Keywords

  • HOMA
  • High-dose Vitamin D
  • IOM RDA
  • Insulin resistance
  • Prediabetes

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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    Fuleihan, G. E. H., Baddoura, R., Habib, R. H., Halaby, G., Arabi, A., Rahme, M., Singh, R. J., Kassem, M., Mahfoud, Z., Hoteit, M., Daher, R. T., & Kassir, M. F. (2016). Effect of Vitamin D replacement on indexes of insulin resistance in overweight elderly individuals: A randomized controlled trial. American Journal of Clinical Nutrition, 104(2), 315-323. https://doi.org/10.3945/ajcn.116.132589