The Association Between Vitamin D Deficiency and Recurrent Tonsillitis: A Systematic Review and Meta-analysis

Objectives The role of vitamin D deficiency has been linked with recurrent upper respiratory tract infections, but its impact on the frequency of tonsillitis is not yet fully understood. The objective of this study is to determine the association between vitamin D deficiency and recurrent tonsillitis based on current literature. Data Source A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Data were collected from online medical databases (PubMed, MEDLINE, EMBASE, and Cochrane Collaboration Registry of Controlled Trials). Review Methods All studies addressing the association of vitamin D deficiency and recurrent tonsillitis prior to March 2019. The data were collected in different phases: screening review using search words and controlled vocabularies followed by detailed review of screened articles based on inclusion and exclusion criteria, then a full review that included screening the references of selected articles. Results Fifty-three studies were potentially eligible; of these, 4 publications met the inclusion criteria and were included in the quantitative synthesis. There was a statistically significant reduction of vitamin D levels in patients with recurrent tonsillitis as compared to healthy controls (mean difference, -10.71; 95% CI, -19.12 to -2.31;P= .01). The odds of vitamin D insufficiency were significantly higher in patients with recurrent tonsillitis as compared to the control group (odds ratio, 4.37; 95% CI, 2.78-6.88;P< .001). Conclusion Vitamin D deficiency was present in patients with recurrent tonsillitis and might be associated with an increase in the risk of recurrent tonsillitis. There is a need to explore these findings via clinical trials based on large populations.