Mouthwash and oral cancer risk quantitative meta-analysis of epidemiologic studies

Background: Use of mouthwash and an increased risk of oral cancer has been a source of controversy for decades. A meta-analysis of epidemiological studies of mouthwash and oral cancer and, specifically, mouthwash containing >25% alcohol, was undertaken. Methods: Summary estimates were obtained with maximum likelihood estimates from random effects models. Sensitivity analyses were conducted to evaluate the influence of various inclusion. Results: Eighteen studies were included in the meta-analysis. There was no statistically significant associations found between regular use of mouthwash and risk of oral cancer (RR=1.13; 95% Cl (0.95-1.35)). There was no significant trend in risk of oral cancer associated with increased daily usage of mouthwash (p=0.11). There was no association between reported use of mouthwash specifically containing alcohol and risk of oral cancer (RR=1.16; 95% Cl (0.44, 3.08)). Conclusions: This quantitative analysis of mouthwash use and oral malignancy revealed no statistically significant associations between mouthwash use and risk of oral cancer, nor any significant trend in risk with increasing daily use; and no association between use of mouthwash containing alcohol and oral cancer risk.