Oral microbiome in older adults with mild cognitive impairment

ABSTRACT

The association between the oral microbiome and mild cognitive impairment (MCI) remains unclear. This study aimed to investigate such an association among Chinese older adults. Participants without dementia were recruited from the community. A battery of neuropsychological tests was administered to evaluate the cognitive function. The diagnosis of MCI was based on Peterson’s criteria. The non-stimulated saliva was collected to extract sequences of the oral microbiome. Forty-seven MCI and 47 cognitively normal participants were included. There was significant difference in alpha diversity and insignificant difference in beta diversity between the two groups of participants. Compared with the cognitively normal group, Gemella haemolysans and Streptococcus gordonii were two significantly decreased species while Veillonella unclassified_Veillonella and Fusobacterium sp._HMT_203 were two significantly increased species in the MCI group. The richness of Gemella haemolysans presented the best discriminate value for MCI with the AUC (Area Under Curve) of 0.707, a cut-off value of 0.008 for relative abundance, the sensitivity of 63.8% and specificity of 70.2%. The dysbiosis of oral microbiome and relative abundance of Gemella haemolysans was significantly associated with MCI. Further studies were needed to develop new treatment strategies targeting the oral microbiome for cognitive impairment.

KEYWORDS:

• Oral microbiome
• mild cognitive impairment
• older adults
• 16S rDNA
• bioinformatic analysis

Acknowledgments

The authors thank Zhaolan Ding, Yan Zhang, Fang Pei, Lirong Yu, Yan Zhou, Zheng Gu, Xiuqin Wu, Jianping Sun, Fengyun Jiang, Weiqing Xue, Zhuqing Xue, and Bingwen Bian for their efforts in study coordination and cognition assessment.

Disclosure statement

No potential conflict of interest was reported by the authors.

Ethics approval and consent to participate

The Medical Ethics Committee of Huashan Hospital, Fudan University approved this study in Shanghai, China. We collected written informed consent from all the participants/their legal guardians.

Availability of data and material

The authors can share their relevant raw data supporting their findings. If any scientist wishes to use them for non-commercial purposes, without breaching participant confidentiality, he or she can contact the authors directly, and they will share their raw data freely with him or her.

Author’s contributions

This work was conceptualized by YZ, XX, and DD and all approved the protocol. Data collection was done by DD, HZ, XZ, YJ, QZ, WW, ZX, XL, and DD. Statistical analysis was undertaken by FW and JL. DD, FW, and DD prepared the manuscript. YZ, XX, and DD are the guarantors of this paper. All authors have read and approved the manuscript, and ensure that this is the case. DD should be contacted for the data.

Additional information

Funding

Shanghai Municipal Science and Technology Major Project [2018SHZDZX01] and ZJ LAB, Key Project of the Ministry of Science and Technology, China [2021YFE0111800] supported data and sample collection. Shanghai Municipal Science and Technology Commission [19JC1413002,17411950704] supported the 16S rDNA Sequencing. The Shanghai Stomatological Hospital School-level Key Department and Innovative Team Project [SSDC-2019-ZDXK01,SSDC-2020-CXTD-A03], Clinical Research Program from Shanghai Health Commission [2020YJZX0117,20194Y0142], Biomedical Engineering Project of Fudan University[yg2021-010], National Natural Science Foundation of China[82071200] and Clinical Research Plan of Shanghai Hospital Development Center [SHDC2020CR4007] supported the sample collection, analysis, interpretation of data and manuscript writing. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.