Oral Health and Risk of Liver Cancer: Evidence from Pooled and Meta-Analyses

Abstract Background: Poor oral health, including periodontal disease and tooth loss, is linked to systemic inflammation and oral microbial dysbiosis, which may promote liver carcinogenesis through the oral–gut–liver axis. However, epidemiologic evidence on oral health and liver cancer risk remains inconsistent. We examined these associations in three prospective US cohorts and conducted a systematic review and meta-analysis of prospective studies. Methods: We pooled data from the Health Professionals Follow-Up Study, Nurses’ Health Study, and Women’s Health Initiative (230,915 participants, 198 liver cancer cases). Oral health, including periodontal disease and tooth loss, was self-reported. Multivariable-adjusted Cox models estimated hazard ratios (HR) and 95% confidence intervals (CI). A systematic review through September 2025 identified four additional prospective studies, which were combined with pooled results in meta-analyses. Results: In the pooled analyses, periodontal disease (HR = 0.99; 95% CI, 0.67–1.47) and complete tooth loss (HR = 1.29; 95% CI, 0.71–2.35) were not associated with liver cancer risk. In the meta-analysis, dominated by one large study, periodontal disease was associated with an increased liver cancer risk (HR = 1.08; 95% CI, 1.03–1.13; n = 4 studies; I2 = 0%). In a linear dose–response meta-analysis, complete tooth loss was associated with an increased risk (HR = 1.32; 95% CI, 1.06–1.66; n = 6; I2 = 0%). Conclusions: The findings of the current investigation suggest that although an association between oral health and liver cancer is possible, the results remain inconclusive. Impact: These findings underscore the need for more studies using harmonized oral health assessments integrating clinical, microbial, and behavioral data to better capture the oral health burden.