Association of oral microbiota with lung cancer risk in a low-income population in the Southeastern USA

Oral microbiome plays an important role in oral health and systemic diseases, including cancer. We aimed to prospectively investigate the association of oral microbiome with lung cancer risk. We analyzed 156 incident lung cancer cases (73 European Americans and 83 African Americans) and 156 individually matched controls nested within the Southern Community Cohort Study. Oral microbiota were assessed using 16S rRNA gene sequencing in pre-diagnostic mouth rinse samples. Paired t test and the permutational multivariate analysis of variance test were used to evaluate lung cancer risk association with alpha diversity or beta diversity, respectively. Conditional logistic regression models were used to evaluate the association of individual bacterial abundance or prevalence with lung cancer risk. No significant differences were observed for alpha or beta diversity between lung cancer cases and controls. Abundance of families Lachnospiraceae_[XIV], Peptostreptococcaceae_[XI], and Erysipelotrichaceae and species Parvimonas micra was associated with decreased lung cancer risk, with odds ratios (ORs) and 95% confidence intervals (CIs) of 0.76 (0.59–0.98), 0.80 (0.66–0.97), 0.81 (0.67–0.99), and 0.83 (0.71–0.98), respectively (all p < 0.05). Prevalence of five pre-defined oral pathogens were not significantly associated with overall lung cancer risk. Prevalence of genus Bacteroidetes_[G-5] and species Alloprevotella sp._oral_taxon_912, Capnocytophaga sputigena, Lactococcus lactis, Peptoniphilaceae_[G-1] sp._oral_taxon_113, Leptotrichia sp._oral_taxon_225, and Fretibacterium fastidiosum was associated with decreased lung cancer risk, with ORs and 95% CIs of 0.55 (0.30–1.00), 0.36 (0.17–0.73), 0.53 (0.31–0.92), 0.43 (0.21–0.88), 0.43 (0.19–0.94), 0.57 (0.34–0.99), and 0.54 (0.31–0.94), respectively (all p < 0.05). Species L. sp._oral_taxon_225 was significantly associated with decreased lung cancer risk in African Americans (OR [95% CIs] 0.28 [0.12–0.66]; p = 0.00012). Results from this study suggest that oral microbiota may play a role in the development of lung cancer.