LAUSR

We read with great interest the study by Coker et al 1 that provided supportive evidence for the role of oral microbiota in gastric cancer. A few studies also highlighted the possible link with oesophageal cancer.2–4 However, there is a lack of robust epidemiologic data on whether periodontal disease and tooth loss, indicators of oral microbial dysbiosis, are associated with these two cancers. Here, we prospectively examined the association of history of periodontal disease and tooth loss with the risk of oesophageal and gastric adenocarcinoma in 98 459 women from the Nurses’ Health Study (1992–2014) and 49 685 men from the Health Professionals Follow-up Study (1988–2016). Dental measures, demographics, lifestyle, and diet were assessed using validated follow-up questionnaires. Self-reported cancer diagnosis was confirmed by review of medical records. We used Cox proportional hazards models to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). We also examined the independent association of history of periodontal disease and tooth loss in a joint analysis. Over 22–28 years of follow-up, we documented 199 cases of oesophageal adenocarcinoma and 238 cases of gastric adenocarcinoma. History of periodontal disease was associated with a 43% and 52% increased risk of oesophageal adenocarcinoma (multivariable-adjusted HR (aHR) 1.43, 95% CI 1.05 to 1.96) and gastric adenocarcinoma (aHR 1.52, 95% CI 1.13 to 2.04) (table …