Table 2.
Study findings for Alzheimer’s disease/cognitive impairment associated with periodontitis
|
Reference |
Study type(s) |
Outcome |
Strength of evidence |
|
Dioguardi et al. 202031 |
SR: 15 studies (6 animal, 1 post-mortem, 4 observational, 1 clinical, 1 case–control, 2 database) |
Investigated whether inflammation from periodontal microbes played a role in the onset & progression of AD Evidence exists for an association but mostly from animal studies rather than human trials Mixed results from observational studies and negative result from clinical trial |
Weak (primarily from animal studies) |
|
Leira et al. 201732 |
SR & MA: 5 studies (2 cross-sectional, 2 case–control, 1 cohort) |
Significant association between periodontal disease and AD (OR 1.69; 95% CI, 1.21–2.35); higher for those with more severe disease. Individuals with AD are less capable of performing oral hygiene (confounding factor if not controlled for in study) |
Strong (for those with AD having periodontal disease but weak for the reverse) |
|
Foley et al. 201733 |
SR & MA: 28 studies but only 1 controlled for oral hygiene |
Negative influence of dementia on oral health status in persons with dementia (argued for causality, i.e., dementia causes periodontal disease) |
Weak (only 1 study explored ability of those with AD to perform oral hygiene) |
|
Gusman et al. 201835 |
SR & MA: 14 studies (varying types) |
Assessed severity of periodontal disease in those with dementia No association found between dementia/AD and severity of periodontal disease |
No evidence |
|
Nadim et al. 202036 |
SR & MA: 5 cohort and 7 case–control studies |
11 studies reported a positive association between periodontal disease and dementia risk RR of dementia related to periodontal disease was only 1.38 (95% CI, 1.01–1.90) |
Weak (borderline meaningful) |
|
Alvarenga et al. 202137 |
SR: 12 studies (8 case–control, 3 cross-sectional, 1 cohort) |
Associations found but results were mixed with other neurodegenerative diseases |
Weak |
|
Hu et al. 202138 |
SR & MA: 5 studies for AD; 5 studies for MCI Combination of cross-sectional, case–control, and 2 cohort |
Results for AD risk compared with non-periodontitis patients was OR 1.78 (95% CI, 1.15–2.76) while risk for MCI was OR 1.60 (95% CI, 1.24–2.06) |
Weak |