Alcohol Consumption and the Diversity of the Oral Microbiome in Postmenopausal Women

Background: Alcohol reduces neutrophil function and decreases salivary flow, which could affect the composition of the oral microbiome. Objective: We hypothesized that the alpha- and I3 -diversity of the oral microbiome and the relative abundance of bacterial taxa would differ by frequency and type of alcohol consumption. Methods: We used a food frequency questionnaire to assess the frequency of consumption of beer, wine, and liquor (drinks/week) in a sample of 1179 postmenopausal women in the Osteoporosis and Periodontal Disease Study. Women were categorized as nondrinkers, drinking <1 drink/wk, >= 1 to <7 drinks/wk, or >= 7 drinks/wk for total alcohol consumption and for beer, wine, and liquor consumption. The composition and diversity of the oral microbiome was assessed from subgingival plaque samples using 16S ribosomal RNA amplicon sequencing. Permutational multivariate analysis of variance (PERMANOVA) was used to examine I3 -diversity (between -sample diversity) in the microbiome between alcohol consumption categories. Analysis of covariance was used to examine the mean alpha-diversity (within -sample diversity), assessed by the Shannon index (species evenness), Chao1 index (species richness), and observed operational taxonomic unit (OTU) count and the mean relative abundance of 245 bacterial taxa across alcohol consumption categories. Results: Over half of the participants (67%) consumed alcohol, with 14% reporting >= 1 drink/d. The I3 -diversity across categories of total alcohol consumption, but not categories of alcohol type, was statistically significantly different (P for PERMANOVA = 0.016). Mean alpha-diversity measures were statistically significantly higher (P < 0.05) in the highest category of total alcohol and wine consumption compared to nondrinkers; no significant associations were found for beer or liquor consumption. The relative abundance of 1 OTU, Selenomonas sp._oral_taxon_133, was significantly lower in the highest level of total alcohol consumption compared to nondrinkers after adjustment for multiple comparisons. Conclusions: Alcohol consumption was associated with the diversity and composition of the subgingival microbiome.