title: A parallel group double-blind RCT of vitamin D3 assessing physical function: is the biochemical response to treatment affected by overweight and obesity?
abstract: Vitamin D may affect skeletal muscle function. In a double-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.
  
  
  BACKGROUND
  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/m(2)) 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/m(2)) 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).
  
  
  CONCLUSIONS
  We found no evidence of an improvement in physical function following vitamin D3 supplementation for 1 year.
authors: School of Medicine and Dentistry, University of Aberdeen, Foresterhill, Aberdeen, AB252ZD, UK.
authors: A D
authors: AD
authors: Wood
authors: K R
authors: KR
authors: Secombes
authors: F
authors: F
authors: Thies
authors: L S
authors: LS
authors: Aucott
authors: A J
authors: AJ
authors: Black
authors: D M
authors: DM
authors: Reid
authors: A
authors: A
authors: Mavroeidi
authors: W G
authors: WG
authors: Simpson
authors: W D
authors: WD
authors: Fraser
authors: H M
authors: HM
authors: Macdonald
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000368:Aged; D000886:Anthropometry / Q000379:methods; D001823:Body Composition; D015992:Body Mass Index; D002118:Calcium / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage / Q000627:therapeutic use*; D004032:Diet; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects*; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D050177:Overweight / Q000097:blood* / Q000503:physiopathology; D010710:Phosphates / Q000097:blood; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D010710:Phosphates; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D; D002118:Calcium
references: Obesity (Silver Spring). 2012 Jul;20(7):1444-8
references: 22262154
references: J Clin Endocrinol Metab. 2003 Jan;88(1):157-61
references: 12519845
references: Methods. 2002 Sep;28(1):14-9
references: 12231183
references: J Am Geriatr Soc. 2011 Oct;59(10):1793-801
references: 22091492
references: Am J Med. 2009 Nov;122(11):1056-60
references: 19854337
references: Am J Clin Nutr. 2000 Sep;72(3):690-3
references: 10966885
references: Osteoporos Int. 2011 Sep;22(9):2461-72
references: 21085934
references: J Clin Endocrinol Metab. 2009 Sep;94(9):3306-13
references: 19549738
references: Eur J Nutr. 2010 Oct;49(7):401-7
references: 20204652
references: Endocr Rev. 2013 Feb;34(1):33-83
references: 23169676
references: J Clin Endocrinol Metab. 2011 Jan;96(1):53-8
references: 21118827
references: Anticancer Res. 2009 Sep;29(9):3713-20
references: 19667169
references: J Clin Endocrinol Metab. 2010 Mar;95(3):1076-83
references: 20061416
references: J Am Coll Nutr. 2008 Apr;27(2):274-9
references: 18689559
references: Public Health Nutr. 2003 May;6(3):313-21
references: 12740081
references: Diabetes. 2010 Jan;59(1):242-8
references: 19833894
references: J Nutr. 2009 Mar;139(3):540-6
references: 19158226
references: Ann Clin Biochem. 1997 Nov;34 ( Pt 6):632-7
references: 9367000
references: Calcif Tissue Int. 2013 Feb;92(2):151-62
references: 22968766
references: Diabetes Care. 2006 Oct;29(10):2244-6
references: 17003300
references: Med Hypotheses. 2003 Nov-Dec;61(5-6):535-42
references: 14592784
references: J Am Geriatr Soc. 2011 Dec;59(12):2291-300
references: 22188076
references: Age Ageing. 2006 Sep;35 Suppl 2:ii37-ii41
references: 16926202
references: Br J Nutr. 2012 Jan;107(1):126-34
references: 21733320
references: Braz J Med Biol Res. 2006 Jan;39(1):91-8
references: 16400469
references: J Clin Endocrinol Metab. 2012 Oct;97(10):3557-68
references: 22865902
references: Cochrane Database Syst Rev. 2009 Apr 15;(2):CD007146
references: 19370674
references: JAMA. 2010 May 12;303(18):1861-2
references: 20460627
references: Osteoporos Int. 1998;8(3):222-30
references: 9797906
references: Am J Clin Nutr. 2004 Sep;80(3):752-8
references: 15321818
references: Ann Intern Med. 2010 Dec 21;153(12):815-25
references: 21173416
references: Bone. 2008 May;42(5):996-1003
references: 18329355
references: Am J Clin Nutr. 2007 Oct;86(4):959-64
references: 17921371
references: J Am Coll Nutr. 2002 Apr;21(2):146S-151S
references: 11999543
references: Rheumatology (Oxford). 2007 Dec;46(12):1852-7
references: 17998225
references: J Clin Endocrinol Metab. 2010 Aug;95(8):3814-27
references: 20463091
references: BMJ. 2009 Oct 01;339:b3692
references: 19797342
references: Ann Intern Med. 2012 Mar 20;156(6):425-37
references: 22431675
references: J Clin Endocrinol Metab. 2009 Apr;94(4):1244-50
references: 19158198
references: J Clin Endocrinol Metab. 2003 Dec;88(12):5766-72
references: 14671166
references: Am J Clin Nutr. 1997 Oct;66(4):929-36
references: 9322570
references: J Clin Endocrinol Metab. 2011 Oct;96(10):2997-3006
references: 21795448
references: J Clin Endocrinol Metab. 2009 Jan;94(1):67-73
references: 18984659
references: Osteoporos Int. 2011 Mar;22(3):859-71
references: 20924748
references: J Biol Chem. 1985 Jul 25;260(15):8882-91
references: 2991224
references: Int J Obes (Lond). 2012 Mar;36(3):387-96
references: 21694701
references: JAMA. 2010 May 12;303(18):1815-22
references: 20460620