RESUMO
OBJECTIVE: The associations between viruses and the cancer have been conducted in several studies while there has been no systematic review and meta-analysis about the association between viral infections and thyroid cancer (TC). Therefore, we investigated the association between viral infection and TC risk. METHODS: Systematic search was done from 1994 to 2019 in Web of sciences (ISI), PubMed, and Scopus databases. Pooled logarithm of odds ratio (OR) and their corresponding 95 % confidence interval (CI) and pooled prevalence of viral infections were calculated to find the association between the viral infections and TC risk and overall prevalence of the viral infections in TC. RESULTS: Twenty-three of 852 original articles were selected and included in the study. According to the results of the random effect meta-analysis, the pooled prevalence of viral infections in the TC patients was 37 % (95 % C. I = 22 %-55 %). In addition, there was a significant association between viral infections (log (OR) = 1.51, 95 % credible interval = 0.68-2.39) and TC risk. The highest associations were observed between TC risk and Simian Vacuolating Virus 40 (SV40) and B19 infections, respectively. The lowest non-significant association was found between TC risk and Poliovirus type 1 infection. The significantly heterogeneity was observed between included studies (Q test: p-value<0.001; I2 = 73.82 %; τ2 = 1.08, 95 % Cr. I = 0.47-1.94). CONCLUSIONS: Results clearly demonstrated the potential pathogenetic association between viral infections and increased risk of TC.