Oral microbiome diversity and diet quality in relation to mortality

Abstract Aim To examine the independent and joint associations of oral microbiome diversity and diet quality with risks of all‐cause and cause‐specific mortality. Materials and Methods We included 7,055 eligible adults from the U.S. National Health and Nutrition Examination Survey (NHANES). Oral microbiome diversity was measured with α‐diversity, including the Simpson Index, observed amplicon sequence variants (ASVs), Faith's phylogenetic diversity, and Shannon–Weiner index. Dietary quality was assessed using the Healthy Eating Index‐2015 (HEI‐2015). Cox proportional hazard models were used to assess the corresponding associations. Results During a mean follow‐up of 9.0 years, we documented 382 all‐cause deaths. We observed independent associations of oral microbiome diversity indices and dietary quality with all‐cause mortality (hazard ratio [HR] = 0.63; 95% confidence interval [CI]: 0.49–0.82 for observed ASVs; HR = 0.68, 95% CI: 0.52–0.89 for HEI‐2015). Jointly, participants with the highest tertiles of both oral microbiome diversity (in Simpson index) and HEI‐2015 had the lowest hazard of mortality (HR = 0.37, 95% CI: 0.23–0.60). In addition, higher oral microbiome diversity was associated with lower risks of deaths from cardiometabolic disease and cancer. Conclusions Higher oral microbiome α‐diversity and diet quality were independently associated with lower risk of mortality.