Effects of vitamin D supplementation on metabolic syndrome parameters in patients with obesity or diabetes in Brazil, Europe, and the United States: A systematic review and meta-analysis.

Plasma 25-dihydroxyvitamin D levels appear reduced in patients with obesity or type 2 diabetes, as reported in several observational studies. However, the association between these reduced hormone levels and metabolic parameters is unclear. In any case, vitamin D supplementation in patients with Metabolic Syndrome is standard.