Last year, more than two dozen researchers from around the world highlighted high cholesterol and vision loss as new risk factors for dementia, publishing their findings in The Lancet in August to emphasize their conclusions.
The report made international headlines, but Bei Wu, the Dean’s Professor in Global Health and Vice Dean for Research at New York University’s Rory Meyers College of Nursing, who has led NIH-funded research since the early 2000s linking cognitive decline, including dementia, to oral health, is calling for the inclusion of oral health as a risk factor.
“Although the [2024] report offers valuable insights, we believe it overlooks the substantial role of oral health in dementia risk,” Wu wrote in a letter published in The Lancet on February 20, urging for its inclusion amid growing evidence, including her team’s recent research, establishing the link.
Wu added that the report’s narrow focus on dental disease as a potential risk factor fails to capture the complexity of oral health issues. “Despite claiming to use recent literature to summarize the best evidence, the authors cited only two studies when discussing oral health,” she wrote.
We found that poor oral health almost triples the risk of dementia compared with diabetes or hypertension
Xiang Qi, PhD, RN, an assistant professor at NYU Rory Meyers College of Nursing
14 risk factors behind dementia
The 2024 report identified hearing loss, high blood pressure, obesity, excessive alcohol consumption, smoking, depression, physical inactivity, diabetes, social isolation, air pollution, traumatic brain injury, high cholesterol, and vision loss as dementia risk factors. However, some risk factors are more severe than others.
“We found that poor oral health almost triples the risk of dementia compared with diabetes or hypertension,” said Xiang Qi, PhD, RN, an assistant professor at NYU Rory Meyers College of Nursing. Qi, whose research intersects gerontology, social epidemiology, psychiatry, and geriatric oral health, noted that oral health is “overlooked.”
“A tremendous amount of study, like ours, has shown that oral health is a significant risk factor for dementia,” Qi added.
Some of the previous studies
Wu, co-director of the NYU Aging Incubator, was lead author of a 2021 study published in JAMDA: The Journal of Post-Acute and Long-Term Care Medicine, which found that tooth loss is a risk factor for cognitive impairment and dementia—and that the risk of cognitive decline increases with each tooth lost.
In 2023, a study published by NYU showed that the combination of diabetes and tooth loss worsens cognitive function and accelerates cognitive decline in older adults. The finding was published in a special issue of the Journal of Dental Research.
In July, Wu and her team published a study examining the link between gum treatment and cognitive decline or dementia risk in older adults with gum problems. They found that those who received gum treatment had a slower decline in cognitive function and a 38% lower risk of developing dementia compared to those who did not.
In December, NYU researchers published a study in Aging Medicine suggesting that wearing dentures may help protect against cognitive decline in older adults.
“We believe that oral health is a significant risk factor for cognitive decline and the onset of dementia,” Wu said.
Many oral health conditions and diseases are preventable with better oral hygiene and regular dental visits, which have been supported by numerous researchers, including our own
Bei Wu, the Dean’s Professor in Global Health and Vice Dean for Research at New York University’s Rory Meyers College of Nursing
Dementia on the rise
The World Health Organization (WHO) estimates the number of people living with dementia will triple by 2050, from 50 million to 152 million due to the aging global population. In Canada, dementia cases are projected to increase from 597,000 in 2020 to over 1.7 million by 2050, according to the Alzheimer Society of Canada. In the U.S., dementia cases are expected to double by 2060, reaching 1 million new cases per year, according to a study by NYU Langone Health.
“Many oral health conditions and diseases are preventable with better oral hygiene and regular dental visits, which have been supported by numerous researchers, including our own,” Wu said. “In this context, poor oral health could potentially be a modifiable risk factor,” she explained, adding that this could help shape policies improving dental care access.
‘New topic’ in 2007
Wu’s and her team’s research follows years of breakthroughs. As far back as 2002, Wu’s work linked cognitive decline to oral health, though it was too early to fully connect it to dementia. However, she published “Cognitive Function and Dental Care Utilization Among Community-Dwelling Older Adults” in the December 2007 issue of the American Journal of Public Health. “The topic was so new at the time,” she recalled.
“Researchers shouldn’t work in silos. We need to think about health outcomes and integrate them into a systematic approach to improving health and well-being,” she added. Wu believes it’s time to include oral health in the discussion, noting that doing so will not only empower dentists to educate the public but also contribute to policies that could help reduce cognitive decline.
