Abstract Body (Do not enter title and authors here): Introduction
Evidence is limited to suggest possible associations between the age at first diagnosis of AF and cognitive decline. The two main goals of this study were: 1) to examine if a younger age at which AF onset occurs is linked to a higher rate of longitudinal cognitive decline; and 2) to ascertain whether AF duration may have a cumulative effect on cognitive decline over time.

Methods
We retrospectively analyzed the Atherosclerosis Risk in Communities Study (ARIC) data from 1990 to 2013. Three cognitive tests were utilized to evaluate cognitive function: the Delayed Word Recall Test (DWRT), the Digit Symbol Substitution Test (DSST), and the Word Fluency Test (WFT). We divided participants into AF onset age groups (≤55, 56-65, and >65 years old) and used follow-up data to investigate the impact of AF onset age on 14-year cognitive deterioration. We also used data from all previous visits to visit 4 to classify AF duration. The association was estimated using the Generalized Estimating Equations (GEE) model.

Results
Table 1 demonstrates the effect of varying the AF onset age and duration on the estimated cognitive change over 14 years of follow-up using our linear models. Participants who experienced their first episode of AF before age 65 showed a significantly higher loss in global cognitive Z score, the DWRT, but not in the DSST (after adjustments) or the WFT. Notably, participants with AF durations longer than 6 years exhibited a larger reduction in overall cognitive Z score, the DWRT, and the DSST. However, only AF durations over 9 years were significantly linked with the WFT. We also found no evidence that physical activities, smoking status, or alcohol consumption were additional risk factors for long-term cognitive impairment.

Conclusion
Our investigation of cognitive decline across 14 years in patients in the ARIC cohort found that earlier onset of AF was linked with faster longitudinal cognitive deterioration. Furthermore, a longer AF illness history was linked to a higher rate of cognitive decline. However, when examining various cognitive scores, the age of onset and disease duration had slightly varied effects.