Treatment with One‐alpha‐hydroxycholecalciferol in Middle‐aged Men with Impaired Glucose Tolerance—A Prospective Randomized Double‐blind Study

Abstract

Experimental evidence suggests a specific role for the active metabolite of vitamin D (1,25(OH)2D3) in insulin secretion. In order to evaluate the possible clinical significance, 65 middle‐aged men with impaired glucose tolerance, and normal serum levels of vitamin D metabolites, were enrolled in a three‐month study where they were given either 0.75 μg alpha‐calcidol (1α(OH)D3) daily or placebo. Indices of glucose and lipid metabolism were evaluated before and after treatment. There were no significant changes during the trial neither for fasting blood glucose, hemoglobin A1C or for the intravenous glucose tolerance between the treatment and the placebo groups, nor were there any consistent changes in insulin values during the glucose tolerance test. Subjects treated with alpha‐calcidol displayed a significant reduction in body weight with an average of 1.1. kg, while those receiving placebo lost no weight. Treatment did not affect the serum lipoprotein values. Thus, a modest dose of active vitamin D, which did not cause elevation of serum calcium, did not provide general improvement of glucose tolerance or of insulin secretion when given to patients with impaired glucose tolerance, but without vitamin D deficiency, over a three‐month period.

Effect of vitamin D supplementation on glycaemic control and insulin resistance: a systematic review and meta‐analysis

“…3). Vitamin D supplementation did not reduce HbA 1c compared with placebo in these studies (between-group difference 0.3 mmol ⁄ mol, 95% CI )2.0 to 2.5 (0.03%, 95% CI )0.18 to 0.23%); I 2 = 0%, 95% CI 0-0%); omission of one study using 1-alpha hydroxylated vitamin D derivatives [23] showed a similar effect [between-group difference 0.3 mmol ⁄ -mol, 95% CI )2.2 to 2.7 (0.03%, 95% CI )0.20 to 0.25%)].…”

“…In those with abnormal glucose tolerance, there was a small but significant reduction in fasting glucose in the vitamin D group compared with placebo ()0.32 mmol ⁄ l, 95% CI )0.57 to )0.07, P = 0.01), with no significant heterogeneity (I 2 = 0%, 95% CI 0-67%). Omitting studies using 1-alpha hydroxylated vitamin D compounds [23,24] did not change these results (between-group difference 0.01 mmol ⁄ l, 95% CI )0.07 to 0.09 for the group with normal fasting glucose; )0.35 mmol ⁄ l, 95% CI )0.61 to )0.08 for the group with abnormal glucose tolerance); similarly, omitting the largest study [23] did not change the point estimate in the group with abnormal glucose tolerance ()0.30 mmol ⁄ l, 95% CI )0.90 to 0.30). Omitting studies where calcium was administered [25][26][27] similarly did not change the outcome in either the group with normal fasting glucose (difference = 0.01 mmol ⁄ l, 95% CI )0.21 to 0.23) or in the group with abnormal glucose tolerance ()0.30 mmol ⁄ l, 95% CI )0.90 to 0.30).…”

The link between obesity and low circulating 25-hydroxyvitamin D concentrations: considerations and implications

“…Specifically, there have been a small number of human clinical studies in which an association between baseline vitamin D status and subsequent weight loss success was identified. For example, Ljunghall et al 89 reported, as a secondary finding in a study designed to investigate the effect of vitamin D supplementation on insulin secretion, that subjects who received low-dose vitamin D (cholecalciferol) supplementation showed a small but significant loss of body weight as compared with subjects receiving placebo. Ortega et al 90 observed in a hypo-caloric weight loss intervention study that baseline serum 25-hydroxyvitamin D was a strong predictor of weight loss.…”

No Effect of High-Dose Vitamin D Treatment on β-Cell Function, Insulin Sensitivity, or Glucose Homeostasis in Subjects With Abnormal Glucose Tolerance: A Randomized Clinical Trial

“…Only two studies used a more sophisticated method for assessment (intravenous glucose tolerance test) (8,10). Regarding insulin sensitivity, a few studies have reported an improvement in insulin sensitivity (13,14), but several did not (8,12,(15)(16)(17)(18)(19).…”