Tooth loss and liver cancer incidence in a Finnish cohort

Periodontal disease, a major cause of tooth loss in adults, may have systemic effects and has been associated with higher risk of several cancer types. However, the associations of periodontal disease or tooth loss with liver cancer have only been examined prospectively in two studies, neither of which had sufficient statistical power. In addition, no studies assessed the potential confounding by viral hepatitis or Helicobacter pylori infection status. In this study, we examined the association between tooth loss and primary liver cancer incidence in a prospective cohort of Finnish male smokers (n = 29,096). We used Cox proportional hazards models to calculate multivariable-adjusted hazard ratios (HRs) and 95% CIs. As a sensitivity analysis, we conducted a nested case-control study within the original cohort to assess confounding by hepatitis B or C virus infection and seropositivity of H. pylori. A total of 213 incident primary liver cancers occurred during a mean follow-up of 17 years. Among these cases, having 11-31 permanent teeth lost (HR 1.42, 95% CI 1.01-1.98) or all 32 teeth lost (HR 1.45, 95% CI 1.00-2.10) was each associated with higher risk of liver cancer, compared to those having 0-10 teeth lost. Adjusting for H. pylori seropositivity yielded a small attenuation of the effect estimate. Greater number of teeth lost was associated with higher risk of primary liver cancer in our study. The role of periodontal infection in the development of liver cancer warrants further investigation.