Effect of Vitamin D supplementation on inflammation: Protocol for a systematic review.

Introduction: The extraskeletal role of Vitamin D is being increasingly recognised. This has important clinical implications, as Vitamin D deficiency has reached epidemic proportions worldwide. Vitamin D has proposed anti-inflammatory properties, yet the role of Vitamin D supplementation in reducing inflammation remains largely unknown. The purpose of this review is to investigate the impact of Vitamin D supplementation on inflammation, and to identify relevant knowledge gaps in the field. Methods and analysis: Medline, CINAHL, EMBASE and All EBM will be systematically searched for randomised controlled trials (RCTs) and systematic reviews of RCTs, comparing Vitamin D supplementation with placebo, usual care or other pharmacological or non-pharmacological interventions. One reviewer will assess articles for eligibility according to prespecified selection criteria, after which 2 independent reviewers will perform data extraction and quality appraisal. Meta-analyses will be conducted where appropriate. Ethics and dissemination: Formal ethical approval is not required as no primary data is collected. This systematic review will identify potential clinical implications of Vitamin D deficiency and supplementation, and will be disseminated through a peer-reviewed publication and at conference meetings, to inform future research on the efficacy of Vitamin D supplementation for inflammation and inflammatory diseases.