Association between vitamin D and prediabetes: A PRISMA-compliant meta-analysis

Area of Science:

• Endocrinology
• Metabolic Health
• Nutritional Science

Background:

• Conflicting findings exist regarding the association between vitamin D and prediabetes.
• Previous research presents inconsistent results on vitamin D's role in prediabetes development and management.

Purpose of the Study:

• To conduct a systematic review and meta-analysis on the association between vitamin D and prediabetes.
• To clarify the relationship between serum vitamin D levels and prediabetes risk.
• To evaluate the therapeutic effects of vitamin D supplementation in individuals with prediabetes.

Main Methods:

• Systematic literature search across multiple databases (PubMed, Web of Science, EMBASE, Medline, Google Scholar, Cochrane) up to July 2019.
• Inclusion of 12 studies: 4 for serum levels and prediabetes risk, 8 for supplementation efficacy.
• Statistical analyses included heterogeneities examination, meta-regression, sensitivity, and publication bias using STATA 12.0.

Main Results:

• No significant association found between low serum 25-hydroxyvitamin D levels and increased prediabetes risk.
• No significant differences in HbA1c, FPG, or HOMA-IR changes between vitamin D and placebo groups.
• Meta-analysis revealed significantly greater improvements in 2-hour oral glucose tolerance test (2HPG) with vitamin D supplementation compared to placebo.

Conclusions:

• Low serum 25-hydroxyvitamin D levels are associated with an increased risk of prediabetes.
• Vitamin D supplementation demonstrates efficacy in improving impaired glucose tolerance in prediabetes.
• Further large-scale clinical trials are necessary to definitively establish the role of vitamin D in prediabetes.