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Clinical Question
In patients with "pre-diabetes," does vitamin D supplementation prevent progression to type 2 diabetes mellitus?
Bottom line
There is no evidence that vitamin D supplementation prevents type 2 diabetes mellitus (T2DM) in patients with normal or mildly low vitamin D levels. Even if one optimistically interprets the data and thinks perhaps the study was underpowered, the number needed to treat would be 42 patients taking huge doses of vitamin D to delay the onset of T2DM in a single person. 1b
Reference
Study design: Randomized controlled trial (double-blinded)
Funding: Government
Setting: Outpatient (any)
Synopsis
Although it is biologically plausible that vitamin D supplementation could delay the onset of diabetes ("It should work…") and there is some data from observational studies supporting this hypothesis, there is no evidence from prospective randomized trials that is actually works. The authors of this study identified adults 30 years and older with a body mass index between 24 and 42 kg/m^2 who met at least 2 of the following criteria: (1) fasting glucose level 100 to 125 mg/dL (5.6 - 6.9 mmol/L), (2) glucose level of 140 to 199 mg/dL (7.8 - 11.0 mmol/L) 2 hours after a 75-g glucose load, and (3) glycated hemoglobin of 5.7% to 6.4% (39 - 47 mmol/L). American Indians, Alaska Natives, Native Hawaiians, and Pacific Islanders were included if they were at least 25 years old. The mean age of participants was 60 years, 45% were female, the mean glycated hemoglobin was 5.9%, and the mean vitamin D level was 28 ng/mL. Approximately 260 in each group had a vitamin D level of 19 ng/mL or lower (the usual definition of normal vitamin D is greater than 20 ng/mL), approximately 440 in each group had a vitamin D level of 20 to 29 ng/mL, and the remainder had a value of 30 ng/mL or higher. Groups were balanced at the start of the study, analysis was by intention to treat, but allocation concealment was not described. All patients were advised to avoid vitamins, medications for diabetes or weight loss, and supplemental calcium. Of 7133 patients screened for the study, 2423 were randomized to receive either vitamin D 4000 IU daily or placebo. After a median follow-up of 2.5 years, 99% of participants were still accounted for (5 deaths in each group and 62 total withdrawals). At the end of the trial, there was no significant difference in the likelihood of developing T2DM between the vitamin D group and the placebo group (hazard ratio 0.88, 95% CI 0.75 - 1.04). The absolute cumulative risks of T2DM were 24.2% in the vitamin D group and 26.6% in the placebo group. The authors did a large number of prespecified subgroup analyses, with most of the hazard ratios for the association between vitamin D and T2DM less than 1.0, but none of the associations were statistically significant. There was no difference in the hazard ratios for patients with baseline vitamin D less than 20 ng/mL compared with those who had higher vitamin D levels. In a post hoc analysis, the likelihood of developing T2DM was lower in those with a very low baseline vitamin D level (< 12 ng/mL), so that group may be worth further study.
Reviewer
Mark H. Ebell, MD, MS
Professor
University of Georgia
Athens, GA
Comments
Subject: Importance of Vitamin -D and about Diabetic protection
Dear Respected Team-CMA-Canada,
Thank you my dear respected SIR/MAM for your kind cooperation towards giving me opportunities to take part in JOULE-CMA-CANADA discussion/comments field as Global Family Doctor at SIG Based in Manikganj-Bangladesh.
Here,I would like to add my comments that -Vitiamin-D is very important for human health ,for children/autistic children /old persons /adults -
Vitiamin-D plays a vital role towards health growth. For human eyes/brain /,body it is very important, for children growth it is very necessary, in the morning we can get SUN LIGHTS which is VITAMIN-D and very necessary for all , even in the winter season of Bangladesh/India /UK/USA/Canada/Australia/Arab countries/African countries /European countries /Norway /Sweden/Finland etcm respected countries VITAMIN-D is very important. But , for Diabetic protection it is not helpful as , it can not work as protection element/medicine towards Diabetic Type -2 . Due to Diabetics all patients /clients should take daily wakings /exercise/yoga /meditation /recreational roles /social works /avoiding fat foods /avoiding much SUGAR /should take night bread instead of night rice . As, bread is good for Diabetic patients.
We wish also the best good health of Diabetic patients/clients to reach good life as per the prescribed medicine and counseling by doctors/heath care practitioners /nurse doctors etc.
Respectfully.
Dr. Muhammad Arif Rana
Global Family Doctor (LDM -224)-WONCA at SIG Based in Manikganj-Bangladesh.
Heath Professional Member-52698-MDS-USA.
International Resident Member ID-44770918 ( Resident No.424504)-SRPC-Canada.
International Resident Member (IMG)-CMAID-680777-CMA-Canada.
Email:muhammadarifrana3@gmail.com
Manikganj-Bangladesh.
Date : October 18-2019-Friday-06:45 PM.
(With heartiest wishes and Respectfully)