Meta-analysis of Vitamin D Deficiency and Risk of Atrial Fibrillation.

BACKGROUND: There are accumulating studies investigating the association between vitamin D status and the risk of atrial fibrillation (AF). However, the results in these studies were inconsistent in regard to the role of vitamin D deficiency in predicting the development of AF. HYPOTHESIS: Vitamin D deficiency is associated increased risk of AF. METHODS: Using PubMed and Embase databases, we searched for records published before March 2016. Additionally, a manual search was conducted using all review articles on this topic. Of the 587 initially identified records, 8 studies with a total of 27 307 patients were finally analyzed. RESULTS: In the categorical variable analysis, vitamin D deficiency was associated with the occurrence of AF (odds ratio: 1.31, 95% confidence interval: 1.06-1.62, P = 0.01). In the continuous variable analysis, higher vitamin D levels appear to protect against the development of AF (odds ratio: 0.92, 95% confidence interval: 0.87-0.97, P = 0.002). However, the association is weak on the pooled analysis of prospective cohort studies focused on new-onset AF (P = 0.07 and 0.04), whereas the pooled analysis of case-control studies mainly assessing for chronic AF strongly support such an association (both P < 0.0001). CONCLUSIONS: Vitamin D deficiency modestly increases the risk of AF. Further studies are needed to determine the if there is a direct causal relationship between vitamin D levels and AF and whether vitamin D supplements will prevent new-onset AF.