The Role of Periodontitis and Periodontal Bacteria in Development of Dementia

Purpose and aims

The study is designed to inquire whether the presence of periodontitis and different periodontopathogenic bacterial strains are associated with dementia diagnosis and with the degree of cognitive impairment in patients evaluated at a Memory clinic (Minnesmottagning). Specifically, by analyzing cerebrospinal fluid (CSF) samples, the investigators intend to clarify whether the alleged mechanisms for Porphyromonas gingivalis (P. gingivalis) in the aetiology of AD are supported in a Swedish population and whether they are specific for P. gingivalis (as compared to other periodontopathogenic bacteria) and Alzheimer type dementia (as compared to other etiological dementia types), respectively.

Research questions

In what proportion of Swedish dementia cases is bacterial DNA from periodontal pathogens, antibodies against periodontal pathogens, gingipain protein from P. gingivalis and gingipain enzyme activity found in CSF? Are these bacteriological findings in the CSF more common or more elevated in individuals that received a diagnosis of dementia, as compared to individuals with a lower level of cognitive dysfunction (e.g. mild cognitive impairment, subjective cognitive impairment, or no diagnosis)? Are measurements of cognitive function, e.g. mini-mental state examination (MMSE) scores, correlated with bacteriological findings in the CSF, including gingipain activity? Is the prevalence of periodontitis higher in participants that received a diagnosis of dementia, as compared to participants with a lower level of cognitive dysfunction? Was the prevalence of periodontitis, 5 - 15 years prior to the diagnostic evaluation, higher in participants that received a diagnosis of dementia, as compared to participants with a lower level of cognitive dysfunction? Are measurements of cognitive function, e.g. mini-mental state examination (MMSE) scores, correlated with periodontitis-related findings? In that case, does the correlation depend on the time interval between the periodontal and the cognitive assessments? Are the above bacteriological findings in the CSF more common or more elevated in participants with severe periodontitis, as compared to participants with mild or no periodontitis? Are periodontitis-related findings correlated with bacteriological findings in the CSF, including gingipain activity? In that case, does the correlation depend on the time interval between the periodontal assessments and the CSF sample? Are P. gingivalis-related findings more common or more pronounced than findings related to other periodontal pathogens in any of these potential relationships? Are P. gingivalis-related findings and other bacteriological findings in the CSF more common or more elevated in participants with AD, as compared to participants with non-Alzheimer dementias? Are P. gingivalis-related findings and other bacteriological findings in the CSF correlated with AD-markers in the CSF, such as β-amyloid, tau and phospho-tau?

Participants