Tooth Loss in Individuals with Dementia: A Swedish Register-Based Cohort Study

Risk factors for dementia include cardiovascular disease, smoking, and diabetes, which also are linked to compromised oral health and periodontal disease. Tooth loss, the hallmark of compromised oral health, is of interest for its systemic effects, including potential impacts on cognitive function. To evaluate tooth loss as a prognostic indicator in dementia, we conducted a register-based cohort study to assess associations of compromised oral health, defined by tooth loss, with mortality risk and progression of cognitive decline. The study population, obtained from linked Swedish nationwide health and quality assurance registries, comprised 3,361 individuals diagnosed with dementia from 2010 to 2013, with follow-up until 2018. Participants were categorized by tooth count: severe tooth loss (<10 remaining teeth), moderate tooth loss (10 to 19 remaining teeth), and a reference group with ≥20 remaining teeth. Mortality rate was analysed by Cox and Poisson regression models, and cognitive decline was assessed by longitudinal analyses of Mini Mental State Examination scores. Analyses were adjusted for demographic and health variables. Tooth loss at the time of dementia diagnosis was not independently associated with increased mortality after covariate adjustment (hazard ratio, 1.12 [95% CI, 0.97 to 1.28] for severe tooth loss vs reference). Annual Mini Mental State Examination scores declined across all groups, with no statistically significant differences among groups. After robust covariate control, no association was observed between tooth loss and increased mortality or cognitive decline in individuals newly diagnosed with dementia. Further studies are needed to determine whether tooth loss is an independent risk factor or a contributing marker in dementia prognosis.