Oral Health and Cognitive Function in Older Adults: A Systematic Review

Background: It has often been argued that there is a relationship between oral health and cognitive decline in late adulthood, but a recent systematic review concluded that it was unclear "how or whether" any relationship exists. However, most of the studies that contributed to this review operationalised cognitive function using a brief cognitive screen and/or dementia status. Objective: An updated systematic review was conducted that focused on how oral health relates to specific cognitive abilities in older adults (specifically, the neurocognitive domains specified in the DSM-5: learning and memory, perceptual motor function, language, executive function, complex attention, and social cognition). Methods: A systematic review was undertaken and completed in August 2018. From a total of 1,304 potentially relevant articles, 23 were identified that assessed oral health and at least one of the specific cognitive domains in an older adult cohort. Results: The most consistent relationships were identified with learning and memory, complex attention, and executive function. For each of these cognitive domains, most studies identified significant unadjusted associations with oral health; where adjustments for covariates were made, at least one of the associations with oral health remained significant in half or more of the studies. Results were less clear for the domains of language and perceptual motor function. No study assessed the relationship between social cognition and oral health. Conclusions: This systematic review provides evidence of an association between learning and memory, complex attention, and executive function with oral health in old age. Gaining a detailed picture of how specific types of cognitive decline relate to oral health has potential implications for earlier identification of older adults who experience oral health problems, and may also inform the development of more effective interventions focused on enhancing oral health outcomes in this group.