Study Finds Link Between Tooth Loss and Cognitive Impairment, Dementia

New data published in JAMDA: The Journal of Post-Acute and Long-Term Care Medicine suggests tooth loss increases risk of cognitive impairment, with each lost tooth compounding that risk. This risk was not seen in older adults with dentures, which could indicate that the cognitive decline associated with tooth loss could be mitigated through timely and effective treatment with dentures, according to the investigators.

The study consisted of a metanalysis of 14 longitudinal studies analyzing tooth loss and cognitive impairment. The aggregate of these studies contained a total of 34,074 participants, 4689 of which experienced diminished cognitive function. The investigators found that adults with more tooth loss had a risk of developing cognitive impairment 1.48 times higher than the average individual, and their risk of being diagnosed with dementia increased by 1.28 times.

“Given the staggering number of people diagnosed with [Alzheimer] disease and dementia each year, and the opportunity to improve oral health across the lifespan, it's important to gain a deeper understanding of the connection between poor oral health and cognitive decline,” said Bei Wu, PhD, Dean's Professor in Global Health at NYU Rory Meyers College of Nursing and co-director of the NYU Aging Incubator, in a press release.

The investigators further analyzed a subset of 8 studies in order to determine if a greater number of lost teeth resulted in a greater risk of cognitive impairment and dementia. According to the results of the study, each additional missing tooth increased the risk of cognitive impairment and dementia diagnosis by 1.4% and 1.1%, respectively.

“This 'dose-response' relationship between the number of missing teeth and risk of diminished cognitive function substantially strengthens the evidence linking tooth loss to cognitive impairment, and provides some evidence that tooth loss may predict cognitive decline,” said Xiang Qi, a doctoral candidate from NYU Meyers, in the release.

Prior studies have suggested a link between cognitive impairment and tooth loss, with researchers providing multiple potential explanations for this association. Missing teeth can result in difficulty chewing, which could contribute to changes in the brain and nutritional deficiencies. Further, research has suggested a connection between cognitive decline and gum disease, which is a leading cause for tooth loss. An alternative possibility is that tooth loss could reflect socioeconomic disadvantages, which are also risk factors for cognitive decline.

“Our findings underscore the importance of maintaining good oral health and its role in helping to preserve cognitive function,” Wu said in the release.


Tooth loss associated with increased cognitive impairment, dementia [news release]. EurekAlert; July 8, 2021. Accessed July 8, 2021.