AF patients under 70 years of age face increased dementia risk

Atrial fibrillation (AF) carries a heightened risk of dementia, especially for those under 70 years of age, according to a European population-based study said to be the largest to date.

In univariate analyses of data from more than 2.5 million adults, AF emerged as a strong predictor of dementia (hazard ratio [HR], 3.39, 95 percent confidence interval, 3.32–3.46 p<0.001), reported one of the study authors Dr Julián Rodriguez García from the Bellvitge University Hospital in Barcelona, Spain. [García JR, et al, EHRA 2025]

Interestingly, age modified the association between AF and dementia risk, García added. Prespecified analyses stratified by age indicated that the strength of the association progressively weakened with increasing age: 45–50 years (HR, 3.29), 50–55 years (HR, 2.16), 55–60 years (HR, 1.73), 60–65 years (HR, 1.60), 65–70 years (HR, 1.30), 70–75 years (HR, 1.18), 75–90 years (HR, 1.11), >90 years (HR, 0.99).

“Dementia is often a multifactorial condition with mixed neuropathological findings rather than a single pathophysiological process. This may explain why AF has a greater impact in younger patients, where it could be one of the primary pathogenic factors,” García and colleagues said in a press statement.

“Conversely, in older individuals, additional contributors to cognitive decline—such as age-related neurodegeneration—may lessen the relative impact of AF,” they added.

Association persists after adjustments

On further analyses, with adjustments for multiple variables (eg, cardiovascular risk factors, cardiovascular disease, alcohol intake, smoking, and neurological diseases), AF remained a significant predictor of dementia, although with a modest impact overall (adjusted HR, 1.04; p<0.001). García noted that the association was most pronounced among participants under 70 years of age (adjusted HR, 1.21; p<0.001) and that AF had a stronger link to early-onset dementia (ie, diagnosis occurring before age 65; adjusted HR, 1.36; p<0.001).

Results of sensitivity analyses that excluded prevalent cases of stroke at baseline and incident stroke during follow-up yielded similar results, with AF showing the strongest association with early-onset dementia (adjusted HR, 1.52; p<0.001).

“AF is a risk factor for stroke, and stroke is a risk factor for dementia. However, the observation that the association between AF and dementia remains unchanged after excluding patients with prior stroke indicates that other mechanisms must be involved in the increased risk of dementia among AF patients,” García and colleagues explained.

“These mechanisms may include silent strokes—meaning those that showed no clinical symptoms and can only diagnosed with CT scan or MRI—and also microinfarcts, and microbleeds,” they added.   

García called for additional studies to evaluate the impact of early AF control on the risk of dementia in younger patients, for whom the consequences may be more severe. “We should now investigate whether early detection strategies and aggressive management of AF in younger patients can help reduce the risk of dementia and change the natural course of the disease.” 

The study involved 2,520,839 adults at least 45 years of age and who had no prior diagnosis of dementia. Of these, 79,820 (3.25 percent) had a recorded diagnosis of AF.

Over an average follow-up of 13 years, the crude incidence of dementia was higher among participants with AF than among those without AF (17.4 vs 5.5 cases per 1,000 person-years).