Tooth Loss May Rank Among the Biggest Dementia Risk Factors

How does tooth loss compare with established risk factors?

The most striking result emerged when the team compared oral health with the 14 modifiable risk factors identified by the influential Lancet Commission in its 2024 update, which helped inform new WHO dementia guidelines released this year. Oral health was absent from that list.

Using a statistical method called population attributable fractions (PAFs) — an estimate of how much a risk factor might contribute to disease across a population if it played a causal role — the researchers calculated that tooth loss could hypothetically account for 7.2 percent of dementia cases in the study. That was the third-largest PAF overall, behind only depressive symptoms (10.5 percent) and social isolation (9.4 percent).

The split by sex was even more remarkable. Among men, tooth loss carried the single largest PAF of every risk factor studied, at 12 percent. Among women, it ranked fourth, at 6.1 percent.

"To our knowledge, this is the first study to quantify and compare the PAFs of poor oral health and a large number of other risk factors for dementia within the same population framework," the team writes.

"In particular, in men, the PAF for tooth loss in our study was substantial and comparable to the top-ranked modifiable risk factors, such as depressive symptoms and social isolation, reported by the Lancet Commission, indicating its relatively large contribution to dementia onset."

Could tooth loss actually cause dementia?

The study does not prove that. The researchers acknowledge important limitations. The JAGES data relies on self-reported information from participants, which may be prone to bias or error. PAFs themselves are speculative: they estimate how risk factors might contribute to disease, but the study does not demonstrate that tooth loss causes dementia, or that preventing tooth loss would prevent cases. Two Lancet Commission factors — high LDL cholesterol and air pollution — could not be assessed with the JAGES data and were excluded.

Still, the authors point to plausible biological pathways. Having fewer teeth can impair chewing and eating, potentially leading to poor nutrition, which is linked to cognitive decline. Tooth loss is also associated with social isolation, itself a dementia risk factor. And tooth loss involves oral inflammation, which may drive systemic inflammation — a process that can contribute to cognitive decline.

The team argues the findings carry major public health implications and that oral health should be integrated into dementia prevention strategies.

"This study demonstrates that tooth loss makes a substantial contribution to dementia incidence, comparable to major established modifiable risk factors identified by the Lancet Commission," the researchers conclude. "Together with the growing body of evidence, these findings argue for re-evaluating oral health as a key dementia risk factor and for its inclusion in future updates of the Lancet Commission report."

Earlier research suggests almost half of dementia cases could be reduced, at least temporarily, through modifiable risk factors. Keeping your teeth may belong on that list.