Atrial Fibrillation and Dementia: Results from the Sao Paulo Ageing & Health Study

Background: Atrial fibrillation (AF) is a controversial risk factor for dementia. Objective: The objective of this study was to assess the association between AF and dementia in the Sao Paulo Ageing & Health (SPAH) study participants. Methods: SPAH is a cross-sectional, population-based study of elderly people living in a deprived neighborhood in Sao Paulo, Brazil. Dementia diagnosis was performed according to the 10/66 study group protocol based on Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria. Diagnosis of AF was made using a 12-lead electrocardiogram (ECG) recording, which was assessed by two cardiologists. Data on demographics and cardiovascular risk factors were also obtained. Results: Dementia was diagnosed in 66 (4.3%) and AF in 36 (2.4%) of 1,524 participants with a valid ECG. The crude odds ratio (OR) for dementia in participants with AF was 2.8 (95% confidence interval [CI]: 1.0-8.1; p=0.06) compared with individuals without AF. When analyzing data according to sex, a positive relationship was found in women (OR 4.2; 95% CI: 1.24-15.1; p=0.03). After age-adjustment, however, this association was no longer significant (OR 2.2; 95% CI: 0.6-8.9; p=0.26). Conclusion: There was no independent association between AF and dementia in this sample. The prevalence of AF may be low in this population owing to premature cardiovascular death. (Arq Bras Cardiol 2012;99(6):1108-1114)