Tooth loss is associated with severe cognitive impairment among older people: findings from a population-based study in Brazil

Abstract

Background: A consistent and low-to-moderate association between markers of oral infection and loss of cognitive function has been demonstrated in the literature. However, such evidence comes from population studies carried out mainly in the USA.

Objectives: To assess the association between tooth loss and loss of cognitive function in older people from Southern Brazil, with particular interest on how age may modify such association. In addition, we also test the association between loss of cognition (exposure) and tooth loss (outcome).

Methods: Data from a baseline population-based cohort study were cross-sectionally analyzed, including tooth loss, cognitive impairment, sex, income, educational attainment, color/race, smoking status and a range of self-reported chronic diseases. Participants (n = 1705) were 60 years of age and over, from a midsized Southern Brazilian city. Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using multivariable logistic and partial ordinal logistic analyses.

Results: Edentate status was associated (OR 3.3; 95%CI 1.2–9.3) with severe cognitive impairment in the fully adjusted model. Moreover, there was an interaction between number of teeth and age on severe cognitive impairment. A weak association between severe cognitive impairment (exposure) and tooth loss (outcome) was identified after the adjustment for potential covariates.

Conclusions: This study lends support to hypothesized association between tooth loss and severe cognitive impairment. Older adults seem to be particularly vulnerable to such effects. However, the bidirectional association between tooth loss and severe cognitive impairment cannot be ruled out.

Keywords:

• tooth loss
• cognition disorders
• cross-sectional studies
• Brazil

Acknowledgements

We thank Dr Nilza Nunes da Silva, Department of Epidemiology, School of Public Health of University of São Paulo, São Paulo, Brazil, for her advice on sample procedures. We would like to thank the Brazilian Institute of Geography and Statistics (IBGE) and the Florianópolis Health Authority staff for their useful help with the practical aspects of the study.