A healthy mouth can also help keep the brain healthy, according to new research published this week. The study, a broad review of existing evidence, found that poor dental health was linked to a higher later risk of cognitive decline and dementia. This increased risk was particularly evident for those who had lost some or all of their teeth.
Numerous studies have indicated that the health of our teeth and gums can influence the body elsewhere, including the brain. But other studies have been less conclusive, and there remains much uncertainty about the strength and direction of this relationship. It’s possible, for example, that the link could be explained by people developing poor dental health as a result of their early dementia, rather than the other way around – an example of what scientists call reverse causation.
In new research by a team from the University of Eastern Finland, they set out to conduct an updated meta-analysis of the evidence so far that would attempt to address these knowledge gaps. They collected and analyzed 47 longitudinal studies that tracked people’s oral and brain health over time, looking specifically at those who had not been diagnosed with dementia at the start of the study.
Ultimately, they found that people with poor oral health were 23% more likely to develop some cognitive decline and 21% more likely to develop dementia. And among the various measures of oral health studied, they also found that tooth loss in particular was independently associated with cognitive decline and dementia.
“Poor periodontal health and tooth loss appear to increase the risk of cognitive decline and dementia,” the authors write in their paper. published Thursday in the Journal of the American Geriatrics Society.
They caution that the evidence they have reviewed is still limited and comes with many caveats, so it is difficult to draw firm conclusions. Many studies have looked at different groups of people (some only included people over 65) or followed them for different time periods, while others may have encountered methodological problems in their design. But the authors say it is the largest review of its kind to date. They also tried to account for reverse causation in a separate analysis and found that this may explain some, but not all, of the link observed here.
In other words, while there may be a genuine causal link between poor oral health and dementia, further research is needed to better understand the specifics of this relationship, including the exact mechanisms. which underpin it. Some scientists theorize, for example, that the bacteria in people with gum disease can help trigger or accelerate the complex chain of events that leads to dementia. The team behind this paper also note that tooth loss could harm the aging brain by robbing people of familiar sensations. And there are probably other factors that can negatively affect the mouth and the brain at the same time, such as nutritional deficiencies.
Of course, keeping your mouth in good shape already has full of advantages, including for heart health. So while there’s still a lot to study here, that’s one more reason to brush your teeth every day and see a dentist regularly. The authors also point out that more needs to be done to ensure that people can have access to good dental care throughout their lives.
“Given the impact of cognitive deterioration on periodontal health, oral health professionals are well placed to monitor and intervene in early changes in periodontal health and oral care, but only if the dental care services are maintained over time and that adequate oral health support is provided in the home when a deterioration in personal care is identified,” they wrote.