Differences in the subgingival microbial composition associated with alcohol intake: A systematic review

OBJECTIVES: This study aimed to conduct a systematic evaluation of the literature on whether individuals exposed to alcohol intake present differences in the subgingival microbial composition compared to those unexposed. METHODS: Five databases (MEDLINE, EMBASE, LILACS, SCOPUS and Web of Science) and one source of grey literature (Google Scholar) were searched by two independent reviewers up to December 2022 according to pre-specified eligibility criteria. No restrictions were imposed regarding the date and language of publication and the periodontal status of the participants. The Newcastle-Ottawa Scale was used for methodological quality appraisal and a narrative synthesis was performed. RESULTS: Eight cross-sectional studies and one cross-sectional analysis nested in a cohort were considered for qualitative analysis, including data of 4636 individuals. Overall, the studies exhibited considerable heterogeneity in terms of characteristics of the participants and microbiological methods. Four studies have high methodological quality. Exposed individuals have higher overall quantity of periodontal pathogens in shallow and moderate to deep pockets. Findings on richness, relative abundance, alpha- and beta-diversity were limited and inconclusive. CONCLUSION: The subgingival microbiota of individuals exposed to alcohol intake has higher overall quantity of red (i.e., P. gingivalis) and orange-complex (i.e., F. nucleatum) bacteria when compared to those unexposed.