Abstract
BACKGROUND: Lower frequency of tooth brushing was thought to be associated with esophageal carcinoma (EC). However, some researchers suggested that this association did not exist or had not yet reached statistical significance. The purpose of this study was to calculate a more precise estimation of the relationship between the frequency of tooth brushing and the risk of EC by combining the results between different studies using the meta-analysis. METHODS: We searched the PubMed, Embase, Web of Science, and Scopus electronic databases up to July 2021. According to PECO approach (Population, Exposure, Comparator and Outcomes), we assessed the association between tooth brushing frequency and EC risk which reported the adjusted risk ratios (adjRR), hazard ratios (adjHR), or odds ratios (adjOR) with 95% confidence interval (CI). The random effects model was used to quantitatively evaluate the combined results. Two researchers independently evaluated the risk bias of the included studies using the Newcastle-Ottawa Scale (NOS). The robustness of results was evaluated by subgroup analysis, sensitivity analysis, and publication bias. RESULTS: In total, we identified 13 articles with 14 case-control studies which included 16,773 participants and 5,673 patients. Pooled results showed the lowest frequency of brushing was significantly associated with an increased risk of EC in comparison to the highest (adjOR: 2.00, 95% CI: 1.61-2.48). There was moderate heterogeneity among included studies (P=0.001, I(2)=61.4%). The original studies included in this meta-analysis were all case-control studies. Study quality was all moderate or above based on NOS score ranges of 6 stars or more. CONCLUSIONS: Available evidence suggests a low frequency of tooth brushing may be an important risk factor for EC. However, higher quality studies should continue to be conducted to investigate the optimal threshold of brushing frequency for the prevention of EC.