Periodontal and Other Oral Bacteria and Risk of Lung Cancer in the Atherosclerosis Risk in Communities (ARIC) Study

Background: Evidence suggests that periodontal disease is asso-ciated with increased lung cancer risk, but whether periodontal pathogens are explanatory is unknown. We prospectively studied associations of prediagnostic circulating antibodies with oral bac-teria and of periodontal bacteria in subgingival plaque with lung cancer. Methods: We included 4,263 cancer-free participants in the Atherosclerosis Risk in Communities study with previously mea-sured serum IgG antibodies to 18 oral bacteria. In 1,287 participants for whom subgingival plaque was collected, counts for 8 periodontal bacteria were previously measured. Incident lung cancers (N = 118) were ascertained through 2015 (median follow-up = 17.5 years). We used Cox regression to estimate multivariable-adjusted associa-tions, including for sums of antibodies to orange (C. rectus, F. nucleatum, P. intermedia, P. micra, and P. nigrescens) and red (P. gingivalis, T. forsythensis, and T. denticola) complex bacteria. Results: Orange complex bacteria antibodies were positively associated with lung cancer [per IQR hazard ratios (HR) = 1.15; 95% confidence intervals (CI), 1.02-1.29], which was stronger in men (HR = 1.27, 95% CI 1.08-1.49), and explained by P. intermedia and P. nigrescens (HR = 1.15; 95% CI, 1.04-1.26). Suggestive positive associations with lung cancer (N = 40) were observed for nucleatum, A. actinomycetemcomitans, and P. gingivalis counts. Significant positive associations were found for the count to anti-body ratio for P. intermedia and P. gingivalis. Conclusions: We identified positive associations with lung cancer for oral bacteria, especially orange complex that are moderately pathogenic for periodontal disease. Impact: This prospective study supports the need for more research on periodontal bacteria in lung cancer etiology. If associations are supported, this may inform novel lung cancer prevention strategies.