A parallel group double-blind RCT of vitamin D3 assessing physical function: is the biochemical response to treatment affected by overweight and obesity?

A.D. Wood, K.R. Secombes, F. Thies, L.S. Aucott, A.J. Black, D.M. Reid, A. Mavroeidi, W.G. Simpson, W.D. Fraser, H.M. Macdonald

    Research output: Contribution to journalArticle

    Abstract

    Summary:Vitamin D may affect skeletal muscle function. In adouble-blind, randomised, placebo-controlled trial, we found that vitamin D3 supplementation (400 or 1,000 I.U. vs. placebo daily for 1 year with bimonthly study visits) does not improve grip strength or reduce falls.Introduction This study aimed to test the supplementation effects of vitamin D3 on physical function and examine associations between overweight/obesity and the biochemical response to treatment.

    Methods:In a parallel group double-blind RCT, healthy postmenopausal women from North East Scotland (latitude—57°N) aged 60–70 years (body mass index (BMI), 18–45 kg/m2)were assigned (computer randomisation) to daily vitamin D3(400 I.U. (n =102)/1,000 I.U. (n =101)) or matching placebo(n =102) (97, 96 and 100 participants analysed for outcomes,respectively) from identical coded containers for 1 year. Grip strength (primary outcome), falls, diet, physical activity and ultraviolet B radiation exposure were measured bimonthly,as were serum 25(OH)D, adjusted calcium (ACa) and phosphate. Fat/lean mass (dual energy X-ray absorptiometry),anthropometry, 1,25-dihydroxyvitamin D and parathyroid hormone were measured at baseline and 12 months.Participants and researchers were blinded throughout intervention and analysis.

    Results:Treatment had no effect on grip strength (mean change(SD)/year=-0.5 (2.5), -0.9 (2.7) and -0.4 (3.3)kg force for 400/1,000 I.U. vitamin D3 and placebo groups, respectively(P =.10, ANOVA)) or falls (P =.65, chi-squared test).Biochemical responses were similar across BMI categories(<25.25–29.99, =30 kg/m2) with the exception of a small change at 12-months in serum ACa in overweight compared to non-overweight participants (P=.01, ANOVA; 1,000 I.U.group). In the placebo group, 25(OH)D peak concentration change (winter to summer) was negatively associated with weight (r =-.268), BMI (r =-.198), total (r =-.278) and trunk fat mass (r =-.251), with total and trunk fat mass predictive of winter to summer 25(OH)D change (P=.01/.004 respectively,linear regression).

    Conclusion:We found no evidence of an improvement in physical function following vitamin D3 supplementation for 1 year.
    Original languageEnglish
    Pages (from-to)305-315
    Number of pages11
    JournalOsteoporosis International
    Volume25
    Issue number1
    DOIs
    Publication statusPublished - 28 Aug 2014

    Keywords

    • adiposity
    • body mass index
    • BMI
    • falls
    • grip strength
    • RCT
    • vitamin D

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    Wood, A. D., Secombes, K. R., Thies, F., Aucott, L. S., Black, A. J., Reid, D. M., Mavroeidi, A., Simpson, W. G., Fraser, W. D., & Macdonald, H. M. (2014). A parallel group double-blind RCT of vitamin D3 assessing physical function: is the biochemical response to treatment affected by overweight and obesity? Osteoporosis International, 25(1), 305-315. https://doi.org/10.1007/s00198-013-2473-8