Does Vitamin D Supplementation Improve Glycemic Control in Type 2 Diabetics?

Acceptable Recruitment Methods Acceptable Method of Selection of Controls Minimization of Bias Were the Confounders Accounted for in the Study Design Are the Results Believable Are They Applicable to Other Populations (Generalizable) Do the Results Fit with Available Evidence Jorde & Figenschau, 2009 Yes, as reflected from the title: Supplementation with cholecalciferol does not improve glycaemic control in diabetic subjects with normal serum 25- hydroxyvitamin D levels Yes, because patients with poor glycemic control were randomly assigned to control and case group. Also appropriate dosages of Vit.

D was used Place of recruitment was not specified. Patients were randomly assigned to both groups. Variables were clearly defined. Yes, the control group was randomly selected from the actual population No blinding method used. Compliance was assessed by asking patients to return unused capsules. Yes, they were: BMI, smoking status, waist to hip ratio, blood pressure, serum calcium, creatinine, lipid profile and 24 hr. urinary calcium. Yes, because the method used was appropriate and acceptable No, because of short sample size and short duration of study.

No, other studies show that Vitamin D improves glycemic control, whereas this study concluded the opposite. Nikooyeh et al., 2011 Yes, as concluded by the title and end conclusion. No because a suboptimal dose of Vitamin D was used. Yes, all participants had impaired fasting glucose levels and were not already taking calcium or Vitamin D supplements. Yes, the control group was randomly chosen. Follow-up bias was minimized by twice a week follow ups. Yes, for example, BMI and anthrometric measures.

Correlations between variables was analyzed using Pearsons No, because vitamin D dosage was suboptimal No, because of short sample size and short duration of study. Yes, available evidence also confirm an improvement of glycemic control with Vitamin D supplementation. Patel et al., 2010 The focus of this article was slightly broader due to the comparison groups between patients receiving subtherapeutic Vitamin D dosing (400 IU daily) and those receiving 1200 IU daily. No, because the mean fasting glucose level of patients was already normal.

Yes, patients had an abnormal HbA1c and low Vitamin D levels. Subjects for the control group were randomly selected from the total population. Compliance was assessed at monthly intervals. Analysis of variance was used to assess other parameters such as, age, gender, ethnicity, duration of diabetes, serum calcium, and BMI Yes, because the method of the study was appropriate and results matched other larger studies. No, because of a short sample size and a short duration of study.

Vitamin D levels of both groups, in this study, increased significantly but did not improve the glycemic control of patients, and therefore the results do not match larger trials. Sabherwal et al., 2010 The topic of the study is clearly focused. However, the conclusion also reflected upon the role of vitamin D in lowering of BMI Data was collected retrtospecitively from clinics.

Subjects had diabetes for longer than 3 years and an abnormal HbA1c Both the control and case group received Vitamin D the groups differed based on deficiency or insufficiency of VitaminD. Not specified Weight was the only confounder measured. Yes, because of.