Subgingival microbiome at different levels of cognition

Nele Fogelholm; Jaakko Leskelä; Muhammed Manzoor; Jacob Holmer; Susanna Paju; Kaija Hiltunen; Hanna-Maria Roitto; Riitta Kt Saarela; Kaisu Pitkälä; Maria Eriksdotter; Kåre Buhlin; Pirkko J Pussinen; Päivi Mäntylä

doi:10.1080/20002297.2023.2178765

Subgingival microbiome at different levels of cognition

J Oral Microbiol. 2023 Feb 19;15(1):2178765. doi: 10.1080/20002297.2023.2178765. eCollection 2023.

Authors

Nele Fogelholm¹, Jaakko Leskelä¹, Muhammed Manzoor¹, Jacob Holmer², Susanna Paju¹, Kaija Hiltunen¹, Hanna-Maria Roitto^{3

4

5}, Riitta Kt Saarela⁶, Kaisu Pitkälä^{7

8}, Maria Eriksdotter^{9

10}, Kåre Buhlin^{1

2}, Pirkko J Pussinen^{1

11}, Päivi Mäntylä^{11

12}

Affiliations

¹ Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland.
² Division of Periodontology, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.
³ Department of Neurosciences, University of Helsinki, Helsinki, Finland.
⁴ Internal medicine and rehabilitation, Division of Geriatrics, Helsinki University Hospital Helsinki, Finland.
⁵ Population health unit, Finnish Institute for Health and Welfare, Helsinki, Finland.
⁶ Department of Social Services and Health Care, Oral Health Care, Helsinki, Finland.
⁷ Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland.
⁸ Unit of Primary Health Care, Helsinki University Hospital, Helsinki, Finland.
⁹ Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden.
¹⁰ Theme Inflammation and Aging, Karolinska University Hospital, Huddinge, Sweden.
¹¹ School of Medicine, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland.
¹² Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland.

Abstract

Oral health and declining cognition may have a bi-directional association. We characterized the subgingival microbiota composition of subjects from normal cognition to severe cognitive decline in two cohorts. Memory and Periodontitis (MINOPAR) include 202 home-living participants (50-80 years) in Sweden. Finnish Oral Health Studies in Older Adults (FINORAL) include 174 participants (≥65 years) living in long-term care in Finland. We performed oral examination and assessed the cognitive level with Mini Mental State Examination (MMSE). We sequenced the 16S-rRNA gene (V3-V4 regions) to analyse the subgingival bacterial compositions. The microbial diversities only tended to differ between the MMSE categories, and the strongest determinants were increased probing pocket depth (PPD) and presence of caries. However, abundances of 101 taxa were associated with the MMSE score. After adjusting for age, sex, medications, PPD, and caries, only eight taxa retained the significance in the meta-analyses of the two cohorts. Especially Lachnospiraceae [XIV] at the family, genus, and species level increased with decreasing MMSE. Cognitive decline is associated with obvious changes in the composition of the oral microbiota. Impaired cognition is accompanied with poor oral health status and the appearance of major taxa of the gut microbiota in the oral cavity. Good oral health-care practices require special deliberations among older adults.

Keywords: Oral health; cognition; cognitive decline; mini mental state examination (MMSE); older adults; subgingival microbiome.

Grants and funding

This work was supported by grants of from the Finnish Dental Society Apollonia and the Päivikki and Sakari Sohlberg Foundation (for PM); from Karolinska Institutet (Clinical Scientist Training Programme and Funds), the Patent Revenue Fund for Research in Preventive Odontology, Stockholm County Council (Steering committee KI/SLL for odontological research), the Swedish Dental Society, CIMED (Center for Innovative Medicine) and the Finnish Dental Society Apollonia (for PJP); the Academy of Finland grants (316777 for SP and 1340750 for PJP); the Sigrid Juselius foundation (for PJP).