Vitamin D supplementation and type 2 diabetes: a substudy of a randomised placebo-controlled trial in older people (RECORD trial, ISRCTN 51647438)

摘要

SIR—Studies in animals show that vitamin D deficiency isnassociated with impaired insulin sensitivity, and that insulinn606nResearch lettersnTable 1. Baseline characteristics of participantsnWith vitamin D3 Without vitamin D3n(n = 2649) (n = 2643)n. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .nAge, mean [SD] 77 [6] 77 [6]nSex, no. (%) female 2240 (84·6) 2241 (84·8)nWhite, no. (%) 2629 (99) 2623 (99)nType of enrolling fracture, no. (%)nProximal femur 459 (17.3) 445 (16.8)nDistal forearm 924 (34.9) 922 (34.9)nOther fractures 1266 (47.8) 1276 (48.3)nWeight, mean [SD] (kg) 65 [13] 65 [12]nCurrent smoker, no. (%) 298 (11.3) 320 (12.1)nDietary calcium intake <400 mg/day, no. (%) 277 (10.5) 256 (9.7)nDietary calcium intake 400–699 mg/day, no. (%) 785 (29.6) 742 (28.1)nCould walk out of doors unaccompanied – no. (%) 2492 (94.4) 2487 (94.3)nDiabetic no. (%) 222 (8.4) 202 (7.6)nSteroids ≥7.5 mg prednisolone/d no. (%) 49 (1.9) 44 (1.7)nsecretion can be increased by vitaminDsupplementation [1].nEpidemiological studies in man show associations betweennlow vitamin levels and glucose intolerance [2].nPittas et al. systematically reviewed the intervention trialnevidence for the role of vitamin D and/or calcium in thenprevention of metabolic syndrome and type 2 diabetes mellitusn[2]. On the basis of evidence from small interventionntrials or post hoc analyses of trials, they concluded that it wasndifficult to be definite whether or not vitamin D and/or calciumnwere important in the prevention of type 2 diabetes,nand that effects might only be manifest in people who werenparticularly at risk of type 2 diabetes.