A recent prospective cohort study published JAMA Network OpenResearchers examine whether a diagnosis of atrial fibrillation (AF) is associated with a higher risk of developing dementia at a younger age.
Study: Age at diagnosis of atrial fibrillation and incident dementia. Image credit: pikselstock/Shutterstock.com
As the world population continues to age, the incidence of all forms of dementia is increasing.
It is the world’s newest health challenge, with its high mortality and lack of effective pharmacological interventions that can prevent or reverse the pathological damage and neuronal degeneration that occurs in dementia.
AF, a type of cardiac arrhythmia, is quite common worldwide and has several similarities with dementia. For example, AF causes stroke, which is a proven risk factor for dementia.
Advanced age and metabolic conditions, such as diabetes and obesity, are other shared risk factors for AF and dementia.
Although epidemiological evidence suggests that people with AF have a higher risk of cognitive deficits and dementia, there is convincing evidence that diagnosis of AF in early life (before age 65) increases the likelihood of developing dementia later.
About the study
In this study, researchers followed evidence of a plausible association between new-onset AF and incident dementia using data from the United Kingdom Biobank (UKB).
In total, 502,411 people aged 40–69 years across England, Wales and Scotland registered with the National Health Service (NHS), UK and living within 25 miles of at least one UKB assessment center agreed to take part. study.
They confirmed AF and age at AF diagnosis and all cases of all-cause dementia, vascular dementia (VD), and Alzheimer’s disease (AD). Study covariates were age, gender, ethnicity, educational level, current drinking and physical activity levels, and depressed mood.
At their baseline visit between 2006 and 2010, they provided their biological samples and physical measurements. In addition, they participated in a touchscreen questionnaire and an oral interview.
Of the 502,411 participants recruited at baseline, the researchers included 433,746 participants in the analysis to determine whether AF was associated with increased risk of developing dementia.
First, they compared their baseline characteristics (AF vs non-AF group) using a t-test (continuous variables) or chi-square test (categorical variables).
Further, they used data from 30,601 participants with AF at baseline or who developed AF during the follow-up period and used Cox proportional hazards models to investigate the relationship between incident dementia, with time lag between baseline and incident dementia. , death or follow-up are represented as time scales.
Specifically, this analysis covered three age groups: <65 years, 65–74 years and ≥75 years, and its results were presented as hazard ratios (HRs) with 95% confidence intervals (CIs), which indicate a relative risk. . Events (dementia or death) occurring in AF versus non-AF groups.
Further, researchers used probability score matching data to investigate the relationship between AF and incident all-cause dementia, VD, and AD.
One participant in each of the three age groups was matched with two participants without AF (1:2 ratio), resulting in 30,600 and 61,200 participants in the AF and AF-free groups.
These analyzes adjusted for several variables such as age, gender, ethnicity, education, and body mass index (BMI).
All statistical analyzes had thresholds of statistical significance p<0.05.
The final analytic sample consisted of 433,746 participants, of whom 54.5% were female and 94.5% white.
The mean age of all participants was 56.9 years. Relative to AF-free participants, those with AF were older (mean age 62.3 years), more male (63.4%), white (97%), and with lower educational status (58.5%).
Dementia occurred in 1.36% of the study population (5,898 participants) at a mean follow-up of 12.6 years.
Dementia rates were higher among participants with AF; Accordingly, there were 1,031 dementia cases with 320 VD and 350 AD among 30,601 AF patients.
Thus, while AF participants were at higher risk of developing generalized dementia and VD than those without AF [adjusted HRs (aHRs), 1.42 and 2.06; 95% CI]The risk of developing AD was not as high (aHR, 1.08; 95% CI).
Furthermore, participants who were younger at AF diagnosis had a higher risk of developing all-cause dementia, AD, as well as VD (aHRs per 10-year reduction, 1.23, 1.27, 1.35; 95% CI).
In a probability score matching analysis, compared with individuals without AF, those with AF diagnosed younger than 65 years had the highest risk of developing all-cause dementia (aHR, 1.82; 95% CI).
The risk of AF diagnosis increased between 65 and 74 years and ≥75 years of age (aHRs, 1.47 and 1.11; 95% CI).
The researchers performed several sensitivity analyses; However, they observed that only ethnicity and apolipoprotein E4 (APOE4) carrier status could modify the association between new-onset AF age and dementia incidence.
Overall, the study results show a quantitative manifestation of the association between AF onset age and incident dementia, highlighting the need to prioritize cognitive function monitoring in AF patients, especially at diagnosis in those younger than 65 years.