Risk of dementia increases with mid-life AF diagnosis

Researchers report a significantly increased risk of dementia in patients diagnosed with atrial fibrillation (AF) in midlife, and a significantly increased risk of early-onset dementia (EOD) as well. Notably, they found that strength of the association weakens with age.

New research was presented March 31, 2025 at EHRA 2025, a scientific congress of the European Society of Cardiology.

“This is the largest European population-based study evaluating the association between AF and dementia,” say the authors that include Dr Julián Rodriguez García of the Electrophysiology and Arrhythmia department of the Bellvitge University Hospital, Barcelona, Spain. “The association between AF and dementia was stronger in patients under 70 and was maximal for early-onset dementia.”

As background, the authors noted that atrial fibrillation causes an irregular heartbeat and affects 2-3% of the general population. Prevalence rises with age.

In this new study, the researchers assessed the independent association between AF and incident dementia in 2,520,839 general population subjects in Catalonia, Spain.

The average follow-up was from baseline was13 years.

The study included subjects who, in 2007, were at least 45 years old and had no prior diagnosis of dementia.

Early-onset dementia (EOD) was defined as a diagnosis occurring before age 65.

The follow-up period extended over 15 years, from 2007 to 2021.

Of the 2,520,839 subjects enrolled at baseline, 79,820 (3.25%) had a recorded diagnosis of AF during follow up.

Among subjects aged 45-50, those with AF were 3.3 times more likely to develop dementia than those without AF. In patients aged over 70 years, no such association was found.

Notably, among subjects diagnosed with AF before the age of 70, AF independently increased the risk of dementia by 21%.

A stronger effect appeared for early-onset dementia, with AF increasing the risk by 36%.

Sub-analyses that removed cases of previous stroke during follow-up provided similar results. AF was associated with a modest increase (6%) in the risk of dementia in the overall population, a stronger association (23% increased risk) in those diagnosed with AF in midlife (<70 years old) and showed the greatest effect on early-onset dementia (52% increased risk).

This means that subjects with AF without a prior stroke are still at an elevated risk of dementia, with the greatest risk for early-onset dementia.

The investigators concluded, “The study demonstrates a significant and strong association in younger patients between two pathologies – atrial fibrillation and dementia – that are among the major health challenges of the 21st century. We should now investigate whether early detection strategies and aggressive management of atrial fibrillation in younger patients can help reducing the risk of dementia and changing the natural course of the disease.”