Association between Benign Paroxysmal Positional Vertigo and Thyroid Diseases: Systematic Review and Meta-Analysis.

Benign paroxysmal positional vertigo (BPPV) is the peripheral vestibular dysfunction that most affects people worldwide, but its etiopathogenesis is still not fully understood. Considering the etiological diversity, some studies highlight the association between BPPV and thyroid diseases.  To investigate the association between thyroid diseases and BPPV.  Systematic review and meta-analysis of epidemiological studies searched in the PubMed, Web of Science, Embase, Cochrane Library, and Scopus databases. Studies that were fully available and investigated the association between BPPV and thyroid diseases were selected. The articles that composed the meta-analysis were analyzed using the dichotomous model, the Mantel-Haenszel statistical test, odds ratio (OR), and a 95% confidence interval (CI). Of the 67 articles retrieved from the databases, 7 met the eligibility criteria of the systematic review, and 4 had data necessary to perform the meta-analysis. Qualitative analysis revealed that the studies were conducted in the European and Asian continents. The predominant methodological design was the case-control type, and thyroid dysfunctions, hypothyroidism, and Hashimoto thyroiditis occurred more frequently. The meta-analysis showed no association between hypothyroidism and BPPV; however, there was a statistically significant relationship between Hashimoto thyroiditis and BPPV.  The meta-analysis results suggest a possible association between BPPV and Hashimoto thyroiditis. Nevertheless, we emphasize the need for further studies to elucidate the evidence obtained.