Assessing the variation within the oral microbiome of healthy adults

Abstract

Over 1000 different species of microbes have been found to live within the human oral cavity where they play important roles in maintaining both oral and systemic health. Several studies have identified the core members of this microbial community, however, the factors that determine oral microbiome composition are not well understood. In this study we exam the salivary oral microbiome of 1049 Atlantic Canadians using 16S rRNA gene sequencing in order to determine which dietary, lifestyle, and anthropometric features play a role in shaping microbial community composition. Features that were identified as being significantly associated with overall composition were then additionally examined for genera and amplicon sequence variants that were associated with these features. Several associations were replicated in an additional secondary validation dataset. Overall, we found that several anthropometric measurements including waist hip ratio, height, and fat free mass, as well as age and sex, were associated with oral microbiome composition in both our exploratory and validation cohorts. We were unable to validate dietary impacts on the oral microbiome but did find evidence to suggest potential contributions from factors such as the number of vegetable and refined grain servings an individual consumes. Interestingly, each one of these factors on their own were associated with only minor shifts in the oral microbiome suggesting that future biomarker identification for several diseases associated with the oral microbiome may be undertaken without the worry of confounding factors obscuring biological signal. ImportanceThe human oral cavity is inhabited by a diverse community of microbes known as the human oral microbiome. These microbes play a role in maintaining both oral and systemic health and as such have been proposed to be useful biomarkers of disease. However, to identify these biomarkers, we first need to determine the composition and variation of the healthy oral microbiome. Within this report we investigate the oral microbiome of 1049 healthy individuals to determine which genera and amplicon sequence variants are commonly found between individual oral microbiomes. We then further investigate how lifestyle, anthropometric, and dietary choices impact overall microbiome composition. Interestingly, the results from this investigation showed that while many features were significantly associated with oral microbiome composition no single biological factor explained a variation larger than 2%. These results indicate that future work on biomarker detection may be encourage by the lack of strong confounding factors.