Dose-Response Meta-Analysis on Tooth Loss With the Risk of Cognitive Impairment and Dementia.
Xiang Qi, Zheng Zhu, Brenda L Plassman and 1 others
PMID 34579934WHAT IT FOUND
More tooth loss was associated with higher risk of cognitive impairment (1.48 times) and dementia (1.28 times).
Risk rose with number of missing teeth; the association was strongest without dentures.
Key findings
01Participants with more teeth lost had 1.48 times higher risk of cognitive impairment and 1.28 times higher risk of dementia than those with fewer teeth lost.
02Each additional missing tooth was associated with a 1.01 times higher relative risk of cognitive impairment and a 1.01 higher dementia relative risk.
03The association with cognitive decline was seen only among people without dentures (RR 1.55), not among denture users (RR 1.00).
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
The studies were observational, so the findings show association but do not prove that tooth loss causes cognitive impairment or dementia. Reverse causality cannot be excluded because cognitive decline may lead to poorer oral hygiene and tooth loss. Attrition was not reported in three cohort studies, so loss to follow-up may have affected the results. Tooth loss was self-reported in five studies, and four studies did not control age or gender. The quality appraisal tool may have underestimated risk of bias for cognitive outcomes.
Declared interests
No authors reported a conflict of interest.
The easy way to misread this
Do not conclude that tooth loss causes dementia or that dentures prevent it. The studies were observational, mechanisms are unproven, and reverse causality cannot be excluded.