Global Cognitive Performance at 4-year Follow-up in Individuals With Atrial Fibrillation

Findings From the Irish Longitudinal Study on Ageing

Triona McNicholas; Katy Tobin; Susan O'Callaghan; Rose Anne Kenny

Disclosures

Age Ageing. 2021;50(6):2192-2198. 

In This Article

Abstract and Introduction

Abstract

Introduction: Atrial fibrillation (AF) has been proposed as a risk factor for cognitive impairment, even in the absence of a history of stroke. This study investigates whether AF is associated with increased risk of cognitive decline in a community-dwelling population of adults over the age of 50.

Methods: Data from the 1st and 3rd waves of The Irish Longitudinal Study on Ageing (TILDA) were used (4-year follow-up period). TILDA is a large prospective cohort study of community-dwelling adults over the age of 50 in Ireland. AF was assessed via electrocardiogram. Global cognitive function was assessed at baseline and follow-up using Montreal Cognitive Assessment (MOCA). Analysis of global cognition was repeated stratifying by age. Mixed-effects Poisson regression was used to assess for change in rate of errors on MOCA and MOCA subdomains.

Results: A total of 3,417 participants were included in the study. Results found that participants with AF had a greater increase in rate of errors on MOCA over 4-year follow-up (incident rate ratio (IRR) 1.18; 95% confidence interval (CI) 1.02, 1.37; P-value 0.023). However, this was no longer significant on controlling for age, sex and level of education (IRR 1.08; 95% CI 0.93, 1.25; P-value 0.332). There was no difference when stratifying by age group, or when separating MOCA into subdomains.

Conclusion: Individuals with AF were more likely to show an increase in rate of errors between waves 1 and 3 (4-year follow-up period) in the TILDA population; however, results were not significant when controlling for age, sex and level of education.

Introduction

Atrial fibrillation (AF) is the most common sustained arrhythmia and has been associated with significant mortality, functional decline and reduced quality of life.[1] AF is associated with increased morbidity and mortality, including a 5-fold increased risk of stroke.[2,3] The prevalence of AF increases with age, and AF has been detected in ~3–4% of healthy volunteers over the age of 60 years,[4] rising to 16% in those aged 85–89 years.[5] Ageing is also associated with a decline in cognitive abilities.[6] It is well established that AF is associated with an increased risk of dementia and cognitive impairment in individuals with a history of previous stroke,[7,8] with emerging evidence suggesting that AF may also be a risk factor for cognitive decline and dementia in the general population, independent of a history of prior stroke.[9,10]

Multiple risk factors for dementia have been identified, including cardiovascular risk factors such as hypertension, diabetes, smoking and stroke.[11] Vascular risk factors have been shown to play a role in not only vascular subtypes of dementia, but also in Alzheimer's disease.[12] AF shares many risk factors with cognitive impairment and dementia. Ott et al.[13] first reported a significant cross-sectional association between AF and dementia in a population-based study, independent of any prior history of stroke. Since this time, multiple studies examining this subject have been completed. Most cross-sectional studies show an association between AF and cognitive impairment,[13–18] but results of longitudinal studies vary.[19–27] Multiple potential mechanisms are proposed for such an association, including cerebral hypoperfusion, vascular inflammation, cerebral small vessel disease, cerebral atrophy and shared risk factors.

The aim of this study was to assess whether community-dwelling individuals, aged ≥50, with AF at baseline were more likely to show a decline in global cognitive function at 4-year follow-up than those without AF.

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