Having both diabetes and tooth loss contributes to worse cognitive function and faster cognitive decline in older adults, according to a new study.
A growing body of research has revealed a similar connection between poor oral health—particularly gum disease and tooth loss—and cognitive impairment and dementia.
Like diabetes, inflammation plays a key role in gum disease, and these inflammatory processes may contribute to cognitive decline. In addition, painful gums and missing teeth can make it difficult to chew, leading to changes in diet that can result in nutritional deficiency.
“Poor oral health, diabetes, and cognitive decline are all connected, and we’re beginning to understand how they may influence and exacerbate one another,” Wu says.
While both diabetes and missing teeth are risk factors for dementia, little research has focused on the effects of having both conditions in the course of cognitive decline. To address this gap, Wu and her colleagues turned to the University of Michigan’s Health and Retirement Study, analyzing 12 years of data (2006–2018) from the longitudinal study to observe cognitive changes over time.
The researchers included 9,948 older adults grouped by age (65 to 74, 75 to 84, and 85 and older) in their analysis. The Health and Retirement Study included measures of memory and cognitive function, assessed every two years, along with questions about tooth loss, diabetes, and other health and demographic factors. In this analysis, the researchers were particularly interested in older adults who had lost all of their teeth.
The relationship among diabetes, tooth loss, and cognitive decline was inconclusive for adults 85 and older, which may be explained by this group having overall greater cognitive impairment, potentially being healthier (as unhealthy individuals may be less likely to survive into their late 80s), or perhaps having more experience managing their diabetes.
For older adults with both poor oral health and diabetes, the researchers stress the importance of regular dental visits, adherence to diabetes treatment and self-care to control blood sugar levels, and cognitive screenings in primary care settings.
Additional co-authors are East Carolina University, Duke University, and NYU.
The National Institutes of Health supported the work.