Diagnosed Dental Diseases, Tooth Loss and the Risk of Primary Liver Cancer in a Nationwide Swedish Cohort

Background and Aim Poor dental health has been shown to increase the risk of several types of cancer, but its association with primary liver cancer (PLC) remains unclear. We aimed to evaluate the association between dental diseases, tooth loss and the risk of PLC. Patients and Methods We conducted a large population‐based retrospective cohort study including 5,893,325 adults registered in the Swedish Dental Health Register between 2009 and 2016. Participants were linked to multiple Swedish national registers to ascertain incident PLC cases. Cox regression analyses were performed to evaluate the association between dental diseases, tooth loss and the risk of PLC, using attained age as the timescale and adjusting for potential confounders. Additionally, in a sibling comparison analysis we controlled for shared genetic and early‐life environmental factors. Results During a mean follow‐up of 6.36 years, 2374 PLC cases were identified through linkage with the Cancer Register: 1856 hepatocellular carcinoma (HCC) and 518 non‐HCC PLC cases. Both caries (hazard ratio [HR] = 1.15, 95% CI: 1.02–1.30) and periodontitis (HR = 1.25, 95% CI: 1.12–1.39) were associated with an increased risk of PLC. Further, a clear dose–response relationship was observed between fewer remaining teeth and PLC risk, with HRs ranging from 1.15 to 1.84 ( p < 0.001) for individuals with fewer teeth compared with those with > 27 remaining teeth. Subtype‐specific analyses showed that caries was associated with non‐HCC PLC, whereas periodontitis was associated with HCC. Tooth loss was more strongly associated with HCC than with non‐HCC PLC. The overall findings were generally consistent across sibling‐controlled, subgroup, and sensitivity analyses. Conclusions Our large population‐based cohort study suggests that caries, periodontitis and tooth loss are associated with an elevated risk of PLC, with distinct patterns of association observed for HCC and non‐HCC PLC.