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Effects of vitamin D 2 or D 3 supplementation on glycaemic control and cardiometabolic risk among people at risk of type 2 diabetes: results of a randomized double‐blind placebo‐controlled trial
Author(s) -
Forouhi N. G.,
Me R. K.,
Sharp S. J.,
Mannan N.,
Timms P. M.,
Martineau A. R.,
Rickard A. P.,
Boucher B. J.,
Chowdhury T. A.,
Griffiths C. J.,
Greenwald S. E.,
Griffin S. J.,
Hitman G. A.
Publication year - 2016
Publication title -
diabetes, obesity and metabolism
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.445
H-Index - 128
eISSN - 1463-1326
pISSN - 1462-8902
DOI - 10.1111/dom.12625
Subject(s) - vitamin d and neurology , medicine , type 2 diabetes , placebo , ergocalciferol , cholecalciferol , endocrinology , confidence interval , diabetes mellitus , gastroenterology , randomized controlled trial , alternative medicine , pathology
Aims To investigate the effect of short‐term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes. Methods In a double‐blind placebo‐controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non‐diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100 000 IU vitamin D 2 (ergocalciferol) or 100 000 IU vitamin D 3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin ( HbA1c ) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C‐reactive protein levels; pulse wave velocity ( PWV ); anthropometric measures; and safety of the supplementation. Results The mean [standard deviation (s.d.)] 25‐hydroxyvitamin D [25( OH )D] 2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D 2 group, and the mean (s.d.) 25( OH ) D 3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D 3 group. There was no effect of vitamin D supplementation on HbA1c : D 2 versus placebo: −0.05% [95% confidence interval ( CI ) −0.11, 0.02] or −0.51 mmol/mol (95% CI −1.16, 0.14; p = 0.13); D 3 versus placebo: 0.02% (95% CI −0.04, 0.08) or 0.19 mmol/mol (95% CI −0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [ D 2 versus placebo: −0.68 m/s (95% CI −1.31, −0.05); D 3 versus placebo −0.73 m/s (95% CI −1.42, −0.03)]. No important safety issues were identified. Conclusions Short‐term supplementation with vitamin D 2 or D 3 had no effect on HbA1c . The modest reduction in PWV with both D 2 and D 3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.