Diabetes and Vitamin D Studies Evaluation Table

Clearly Focused Issue

Appropriate Method to Answer the Research Question

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

Witham et al., 2010

This is a follow-up study. The issue is whether patients with a vitamin D level of higher than 250 HD will gain a benefit from vitamin D supplementation.

A positive result is defined by reaching a level of 75 nmol or above. This is considered the level for optimum health.

Patients for the study were selected from general practice and diabetes specialty offices based on a positive type 2 diabetes mellitus diagnosis in accordance with the requirement set forth by the World Health Organization.

The group was divided into three sub-groups. The control had a placebo. The other two groups were given 100,000 IU and 200,000 IU of vitamin...

The actual grouping was unknown to the researchers until after the study was complete and the data entered.
The primary confounder accounted for in this study was whether vitamin D always gives a positive reaction. This was accounted for by using two differing doses. If the research theory is correct, then the larger dose will provide an improved outcome.

The results were that neither dosage significantly improved the patient's diabetes symptoms.

These findings are applicable to all populations of those with type 2 diabetes.

This result does fit within the available evidence, as all studies have found some, but no substantial improvement.

George et al., 2012

This is a literature study that reviews all the most recent study findings over the past five years and forms a conclusion on these studies.

The study reviews all studies on the subject published in the past 5 years using searches in accordance with the Cochrane Collaboration.

The following groups of studies were reviewed: vit D. Vs. placebo, vit D. And…