Atrial Fibrillation and Risk of Dementia: A Prospective Cohort Study

<jats:p> <jats:bold>OBJECTIVES:</jats:bold> To determine whether atrial fibrillation (AF) is associated with risk of incident dementia or Alzheimer's disease (AD), beyond its effect on stroke. </jats:p> <jats:p> <jats:bold>DESIGN:</jats:bold> Prospective cohort study. </jats:p> <jats:p> <jats:bold>SETTING:</jats:bold> An integrated healthcare delivery system. </jats:p> <jats:p> <jats:bold>PARTICIPANTS:</jats:bold> A population‐based sample of 3,045 community‐dwelling adults aged 65 and older without dementia or clinical stroke followed from 1994 to 2008. </jats:p> <jats:p> <jats:bold>MEASUREMENTS:</jats:bold> AF was identified from health plan electronic data using <jats:italic>International Classification of Diseases, Ninth Revision</jats:italic> , codes from inpatient and outpatient encounters. Covariates came from self‐report, study measures, and health plan data. Participants were screened every 2 years using the Cognitive Abilities Screening Instrument (range 0–100), with detailed neuropsychological and clinical assessment of those scoring less than 86. A multidisciplinary consensus committee determined diagnoses of all‐cause dementia and possible or probable AD using standard research criteria. </jats:p> <jats:p> <jats:bold>RESULTS:</jats:bold> AF was present in 132 (4.3%) participants at baseline and was diagnosed in 370 (12.2%) more over a mean of 6.8 years of follow‐up; 572 participants (18.8%) developed dementia (449 with AD). The adjusted hazard ratio associated with AF was 1.38 (95% confidence interval (CI)=1.10–1.73) for all‐cause dementia and 1.50 (95% CI=1.16–1.94) for possible or probable AD. Results were similar for participants with and without clinically recognized stroke during follow‐up and in sensitivity analyses examining only probable AD. </jats:p> <jats:p> <jats:bold>CONCLUSION:</jats:bold> AF is associated with higher risk of developing AD and dementia. Future studies should examine whether specific treatments, including optimal anticoagulation, can decrease this risk. </jats:p>