Tooth Loss and Head and Neck Cancer: A Meta-Analysis of Observational Studies

BACKGROUND [corrected] Epidemiological studies have shown that tooth loss is associated with risk of head and neck cancer (HNC); however, the results were inconsistent. Therefore, we conducted a meta-analysis to ascertain the relationship between tooth loss and HNC. METHODS We searched for relevant observational studies that tested the association between tooth loss and risk of HNC from PubMed and were conducted up to January 30, 2013. Data from the eligible studies were independently extracted by two authors. The meta-analysis was performed using the Comprehensive Meta-Analysis 2.2 software. Sensitivity and subgroup analyses were conducted to evaluate the influence of various inclusions. Publication bias was also detected. RESULTS Ten articles involving one cohort and ten case-control studies were yielded. Based on random-effects meta-analysis, an association between tooth loss and HNC risk was identified [increased risk of 29% for 1 to 6 teeth loss (OR = 1.29, 95% CI = 0.52-3.20, p = 0.59), 58% for 6 to 15 teeth loss (OR = 1.58, 95% CI = 1.08-2.32, p = 0.02), 63% for 11+ teeth loss (OR = 1.63, 95% CI = 1.23-2.14, p<0.001), 72% for 15+ teeth loss (OR = 1.72, 95% CI = 1.26-2.36, p<0.001), and 89% for 20+ teeth loss (OR = 1.89, 95% CI = 1.27-2.80, p<0.001)]. The sensitivity analysis shows that the result was robust, and publication bias was not detected. CONCLUSIONS Based on the current evidence, tooth loss is probably a significant and dependent risk factor of HNC, which may have a dose-response effect. People who lost six or more teeth should pay attention to symptoms of HNC, and losing 11 teeth or 15 teeth may be the threshold.