Co-occurring Diabetes and Tooth Loss Linked to Worse, Faster Cognitive Decline

Adults aged 65 to 74 years with co-occurring diabetes and toothlessness are more likely to experience worse and faster cognitive decline, according to research published in Journal of Dental Research.

Diabetes is already a recognized risk factor for dementia, and tooth loss, or edentulism, has been linked to cognitive impairment and dementia. However, research on the effects of co-occurring diabetes and edentulism on cognitive decline is limited.

This study included a nationally representative cohort of 9948 older adults who were part of the Health and Retirement Study (HRS) between 2006 and 2018. Of this sample, 5440 were aged 65 to 74 years, 3300 were aged 75 to 84 years, and 1208 were 85 years or older.

During their enrollment in the HRS, 93.8% of adults in the youngest age category had time-repeated cognitive measures, and 41.2% of them completed the assessment in all 3 waves of the study. These percentages decreased as age increased. Among adults in the middle age category, these percentages were 87.6% and 20.4%, respectively. Among adults aged 85 and older, these percentages were 72.0% and 2.8%, respectively.

The researchers compared participants’ baseline characteristics by age cohort and used linear mixed-effect models for each age cohort to model participants’ cognitive trajectories between 2006 and 2018. The HRS Telephone Interview for Cognitive Status score ranged from 0 to 35, with a higher score indicating better cognition.

Regardless of diabetes or edentulism status, adults aged 65 to 74 years had the highest cognitive score by age cohort, with a mean (SD) score of 23.07 (0.07). Meanwhile, adults aged 85 and older had the lowest mean score of 18.53 (0.17).

The percentages of older adults with both diabetes and edentulism were 6.0%, 6.7%, and 5.0% in the younger, middle, and oldest age groups, respectively. Respective percentages of older adults with neither condition were 63.5%, 60.4%, and 58.3%. Some adults also had only one condition or the other.

Older adults with co-occurring diabetes and edentulism aged 65 to 74 years (β, −1.12; 95% CI, −1.56 to −0.65; P < .001) and aged 75 to 84 years (β, −1.35; 95% CI, −2.09 to −0.61; P < .001) had worse cognitive function compared with their counterparts with neither condition.

When looking at the rate of cognitive decline relative to adults with neither condition from the same age cohort, adults aged 65 to 74 with both conditions showed cognitive decline at a higher rate (β, −0.15; 95% CI, −0.20 to −0.10; P < .001). In this same age group, diabetes alone (β, −0.09; 95% CI, −0.13 to −0.05; P < .001) and edentulism alone (β, −0.13; 95% CI, −0.17 to −0.08; P < .001) were each linked to accelerated cognitive decline. Among adults aged 75 to 84 years, edentulism alone was also associated with accelerated cognitive decline (β, −0.10; 95% CI, −0.17 to −0.03; P < .01).

The researchers found no significant difference in cognitive decline rates based on diabetes and edentulism status among those 85 years and older. They concluded that co-occurrence of diabetes and edentulism led to worse cognitive function and faster cognitive decline in older adults aged 65 to 74 years compared with adults in other age groups and with different condition statuses.

“The findings have important policy and clinical implications for preventing cognitive decline among older adults, especially those with diabetes and poor oral health,” the authors said.

According to them, this includes the following:

• Encouragement of those with diabetes and poor oral health to visit their dentist regularly and adhere to the diabetes self-care protocol
• Regular cognitive screening in the primary care setting for older adults with diabetes and poor oral health and diabetes
• Emphasis of the link between oral health and cognition during routine dental cleanings

Reference

Wu B, Luo H, Tan C, et al. Diabetes, edentulism, and cognitive decline: a 12-year prospective analysis. J Dent Res. Published online March 12, 2023. doi:10.1177/00220345231155825