The pathway from cognitive impairment to caries in older adults: A conceptual model

Caries significantly increases in people with cognitive impairment (PWCI). However, the interrelationships among cognitive impairment, dentally related function (DRF), oral hygiene, and caries remain unclear, increasing difficulties to care appropriately for PWCI. In this study, the researchers tested a conceptual model in which impaired DRF acts as a mediator between cognitive impairment and poor oral hygiene, which then leads to caries.

The researchers recruited 68 older adult dentate participants with normal to severely impaired cognition from 3 assisted-living communities in North Carolina. Within 1 week of a calibrated oral examination performed by a geriatric dentist, a trained examiner blinded to the oral examination results conducted cognitive and functional assessments. The researchers conducted statistical analyses to examine the mediating effect of DRF on the relationship between cognitive impairment and oral hygiene or caries.

Cognitive impairment (β = 0.05; standard error [SE], 0.02; P = .017) and DRF (β = -0.07; SE, 0.02; P = .005) were significantly associated with oral hygiene. However, the association between cognitive impairment and oral hygiene was greatly reduced and became nonsignificant after controlling for DRF (β = 0.01; SE, 0.03; P = .430), suggesting that the effect of cognitive impairment on oral hygiene was mediated by DRF. DRF accounted for 80% of the total effect of cognitive impairment on oral hygiene. The ratio of the indirect effect to the total effect was .8. Associations between either cognitive impairment or DRF and caries were not significant, but oral hygiene was significantly associated with caries (β = 0.87; SE, 0.28; P < .001).

DRF mediated the association between cognitive impairment and oral hygiene. It accounted for 80% of the total impact of cognitive impairment on oral hygiene, which was associated with increased caries in PWCI.

As a result of cognitive impairment, impaired DRF plays a critical role in the pathway from cognitive impairment to oral health decline. Therefore, DRF assessment should be a standard component of geriatric dental assessment. A functionally-tailored oral hygiene intervention is essential to improve oral health for persons with cognitive impairment.