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Oral Microbiome and Its Emerging Role in Alzheimer\'s Disease: A Comprehensive Review
Alka Singh, A. K. Mittal, Narsingh Verma. Journal of Acute Care Trauma and Emergency Medicine, 2026-06-29
Topic: Amyloid, tau and blood-test diagnosis
Alzheimer's disease (AD) affects ~55 million people globally and is projected to rise steeply with population ageing.While genetic risk and amyloid biology remain central to AD research, the limited clinical success of anti-amyloid strategies has encouraged exploration of additional contributors, including chronic peripheral infections.The oral microbiome comprises >700 species organized in biofilms, and periodontal disease-highly prevalent in adults-can drive sustained systemic inflammation.Increasing evidence has linked periodontitis and tooth loss with faster cognitive decline and higher dementia risk, raising the possibility of an oral-brain connection.This narrative review summarized literature (PubMed, Scopus, Google Scholar; January 2000-December 2024) on oral dysbiosis and AD, prioritizing systematic reviews and human studies while using animal and laboratory data to explain mechanisms.Proposed pathways include cytokine-mediated neuroinflammation, blood-brain barrier dysfunction, and the presence of microbial components in neural tissue.In particular, Porphyromonas gingivalis and its gingipains have been reported in AD brain samples and experimental models, with downstream effects on amyloid-β dynamics, tau processing, and microglial activation.Other organisms, including Treponema species, Fusobacterium nucleatum, Actinomyces naeslundii, Candida albicans, and herpesviruses (e.g., HSV-1), have been discussed as potential contributors through inflammatory and oxidative stress pathways.However, much mechanistic support is derived from animal or in-vitro studies, which cannot be equated with human causation.Reverse causality and confounding by frailty, nutrition, and socioeconomic factors remain important concerns, and interventional human trial evidence demonstrating neurological benefit from modifying oral health is still limited.Overall, oral health represents a plausible, potentially modifiable factor relevant to AD risk biology, warranting cautious interpretation and further longitudinal and interventional clinical research.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Singh, A., Mittal, A. K., & Verma, N. (2026). Oral Microbiome and Its Emerging Role in Alzheimer\'s Disease: A Comprehensive Review. Journal of Acute Care Trauma and Emergency Medicine. https://doi.org/10.5005/jactem-11048-0030
Vancouver
Singh A, Mittal AK, Verma N. Oral Microbiome and Its Emerging Role in Alzheimer\'s Disease: A Comprehensive Review. Journal of Acute Care Trauma and Emergency Medicine. 2026. doi:10.5005/jactem-11048-0030.
BibTeX
@article{singh2026-ae0cd918,
author = {Singh, Alka and Mittal, A. K. and Verma, Narsingh},
title = {{Oral Microbiome and Its Emerging Role in Alzheimer's Disease: A Comprehensive Review}},
journal = {Journal of Acute Care Trauma and Emergency Medicine},
year = {2026},
doi = {10.5005/jactem-11048-0030},
url = {https://doi.org/10.5005/jactem-11048-0030}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
Key findings
- Alzheimer's disease (AD) affects ~55 million people globally and is projected to rise steeply with population ageing.While genetic risk and amyloid biology remain central to AD research, the limited clinical success of anti-amyloid strategies has encouraged exploration of additional contributors, in
Why it matters
This review summarizes evidence linking oral bacteria and periodontal disease to faster cognitive decline and higher dementia risk, with proposed pathways including neuroinflammation, blood-brain barrier dysfunction, and microbial components in neural tissue. It is a narrative review of possible contributors to Alzheimer's disease, not a trial showing that treating oral infection prevents or cures it.
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Study details
- Study designlongitudinal study
- Evidence strengthModerate
How this study scored 36/100
Published in a peer-reviewed journal, and it is a longitudinal study following the same people over time. Scored zero for sample size, effect reported, studied in people and randomized / blinded because the record does not state it. We have no data on senior author's track record, so that was left out: it earned 35 of the 96 points we could judge it on, which is 36 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Journal of Acute Care Trauma and Emergency Medicine) |
| Journal's citation record | 0 / 4 | Journal of Acute Care Trauma and Emergency Medicine: journal h-index 1 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 5 / 5 | 2026 — within 1 year(s) of the newest study here |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomized / blinded | 0 / 2 | No randomization or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 0 / 7 | Cited 0 times (OpenAlex, 2026-10-10) |
| Citations per year | 0 / 5 | 0.0 citations a year over 2 year(s) since 2026 |
| Impact for its field and year | 0 / 6 | Cited 0.0× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 0 / 4 | Cited 0 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | — / 4 | OpenAlex's profile for last-listed author Narsingh Verma holds only 6 work(s), too few to judge a track record — left out of this score |
| Institution's track record | 0 / 3 | Government of Uttar Pradesh: institution h-index 65 (OpenAlex) |
| Multicenter collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 1 / 2 | Not in PubMed, but has a DOI |
| Free to read | 2 / 2 | Free to read |
| Points | 35 / 96 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 35 of the 96 points we could judge it on is 36 out of 100. |
| Total | 36 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.5005/jactem-11048-0030
- Original source →
- Free full text: Journal of Acute Care Trauma and Emergency Medicine →
Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).
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