AimTo examine association between subgingival microbial signatures and levels of cognitive impairment in older adults.Materials and MethodsWe analysed subgingival plaque samples and 16S ribosomal RNA sequences for microbiota among 165 participants (normal controls [NCs]: 40, subjective cognitive decline [SCD]: 40, mild cognitive impairment [MCI]: 49 and dementia: 36).ResultsThe bacterial richness was lower among individuals with worse cognitive function, and subgingival microbial communities differed significantly among the four groups. Declining cognitive function was associated with decreasing relative abundance of genera Capnocytophaga, Saccharibacteria_genera_incertae_sedis, Lautropia and Granulicatella, and increasing abundance of genus Porphyromonas. Moreover, there were differentially abundant genera among the groups. Random forest model based on subgingival microbiota could distinguish between cognitive impairment and NC (AUC = 0.933, 95% confidence interval 0.873–0.992). Significant correlations were observed between oral microbiota and sex, Montreal Cognitive Assessment (MoCA) score and Mini‐Mental State Examination score. Partial correlation analysis showed that Leptotrichia and Burkholderia were closely negatively associated with the MoCA score after adjusting for multiple covariates. Gene function was not significantly different between SCD and NC groups, whereas three homozygous genes were altered in MCI patients and two in dementia patients.ConclusionsThis is the first study to demonstrate an association between the composition, function and metabolic pathways of subgingival microbiota and different levels of cognitive function among older individuals. Future cohort studies should assess its diagnostic usefulness for cognitive impairment.

中文翻译：

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具有不同认知功能水平的老年人的独特龈下微生物特征


目的检查龈下微生物特征与老年人认知障碍水平之间的关联。材料和方法我们分析了 165 名参与者的龈下牙菌斑样本和 16S 核糖体 RNA 序列的微生物群 （正常对照 [NCs]：40，主观认知能力下降 [SCD]：40，轻度认知障碍 [MCI]：49 和痴呆：36）。结果认知功能较差个体细菌丰富度较低，龈下微生物群落在 4 组间差异显著。认知功能下降与噬细胞菌属、Saccharibacteria_genera_incertae_sedis属、Lautropia 属和 Granulicatella 属的相对丰度降低以及卟啉单胞菌属丰度的增加有关。此外，各组间属的丰富性存在差异。基于龈下微生物群的随机森林模型可以区分认知障碍和 NC （AUC = 0.933,95% 置信区间 0.873-0.992）。观察到口腔微生物群与性别、蒙特利尔认知评估 （MoCA） 评分和简易精神状态检查评分之间存在显著相关性。偏相关分析显示，在调整多个协变量后，Leptotrichia 和 Burkholderia 与 MoCA 评分呈密切相关。SCD 组和 NC 组之间的基因功能无显著差异，而 MCI 患者的 3 个纯合基因发生改变，痴呆患者有 2 个纯合基因发生改变。结论这是第一项证明龈下微生物群的组成、功能和代谢途径与老年人不同认知功能水平之间存在关联的研究。未来的队列研究应评估其对认知障碍的诊断有用性。