New research hints at a connection between poor oral health and dementia

It is obvious that poor oral health brings along many diseases. The latest study, on the other hand, suggests that it has revealed another problem that may never come to mind.

The new study carried out by the University of Eastern Finland found that poor oral health is linked to an increased risk of cognitive decline and dementia.

This increased risk was especially apparent for those missing some or all of their teeth.

The results were published in the Journal of the American Geriatrics Society on September 8.

The University of Eastern Finland team set out to update a previous meta-analysis of the available data in order to try to account for these knowledge gaps.

They gathered and examined data from 47 long-term studies that followed participants' dental and cognitive health throughout time, paying particular attention to those who were free of dementia at the beginning of the study.

In the end, scientists discovered that those with poor dental health were 23% more likely to experience cognitive decline in the future and 21% more likely to experience dementia.

Additionally, they discovered that tooth loss, in particular, was an independent risk factor for dementia and cognitive impairment among the numerous oral health indicators examined.

“Poor periodontal health and tooth loss appear to increase the risk of both cognitive decline and dementia,” the authors wrote in their paper.

It is just a beginning

Sam Asher, the study's lead author and a public health researcher at the University of Eastern Finland, wrote to Inverse that further research is needed to fully understand how mouth health and brain health are related.

“This may lower dementia risk to some extent, although at the moment, we cannot say for sure how much," he said.

He also said that periodontal health is a "modifiable risk factor," meaning we have some control over it.

It is never too late

Oral health deteriorates as we age. We may even neglect our oral health from time to time.

“Maintaining oral health is perhaps even more important for people who already have some degree of cognitive decline or dementia," said Asher.

“Overall, practicing adequate oral hygiene measures is paramount for maintaining good oral health, which may positively influence health and wellbeing in general."

Study abstract:

Emerging evidence indicates that poor periodontal health adversely impacts cognition. This review examined the available longitudinal evidence concerning the effect of poor periodontal health on cognitive decline and dementia. Comprehensive literature search was conducted on five electronic databases for relevant studies published until April 2022. Longitudinal studies having periodontal health as exposure and cognitive decline and/or dementia as outcomes were considered. Random effects pooled estimates and 95% confidence intervals were generated (pooled odds ratio for cognitive decline and hazards ratio for dementia) to assess whether poor periodontal health increases the risk of cognitive decline and dementia. Heterogeneity between studies was estimated by I2 and the quality of available evidence was assessed through quality assessment criteria. Adopted search strategy produced 2132 studies for cognitive decline and 2023 for dementia, from which 47 studies (24 for cognitive decline and 23 for dementia) were included in this review. Poor periodontal health (reflected by having periodontitis, tooth loss, deep periodontal pockets, or alveolar bone loss) was associated with both cognitive decline (OR = 1.23; 1.05–1.44) and dementia (HR = 1.21; 1.07–1.38). Further analysis, based on measures of periodontal assessment, found tooth loss to independently increase the risk of both cognitive decline (OR = 1.23; 1.09–1.39) and dementia (HR = 1.13; 1.04–1.23). Stratified analysis based on the extent of tooth loss indicated partial tooth loss to be important for cognitive decline (OR = 1.50; 1.02–2.23) and complete tooth loss for dementia (HR = 1.23; 1.05–1.45). However, the overall quality of evidence was low, and associations were at least partly due to reverse causality.