Atrial Fibrillation Not a Risk Factor for Dementia in Very Elderly
Atrial Fibrillation Not a Risk Factor for Dementia in Very ElderlyNEW YORK (Reuters Health) May 10 - While atrial fibrillation is a significant risk factor for stroke in the very old, it does not predict dementia, according to findings published in the May issue of Stroke.
"Atrial fibrillation (AF) is a well-known risk factor for stroke in the elderly," Dr. Tuula Pirttila, of Kuopio University Hospital, Finland, and colleagues write. "Several studies have shown that AF predicts the development of poststroke dementia, whereas others have found no such association."
In a prospective 9-year population-based study in Vantaa, a town in Southern Finland, the researchers examined the association between AF, stroke, dementia, and their correlation with brain pathology in subjects 85 years of age or older.
A total of 553 subjects were examined by a neurologist. The diagnosis of AF was made by ECG or medical record review. During a mean follow-up of 3.5 years, 479 subjects died, and postmortem neuropathological examinations were performed in 306.
Overall, 122 subjects (22.1%) were diagnosed with AF. A significant association was observed between AF and stroke at baseline. Stroke was present in 39 (32%) of 122 subjects with AF and in 72 (16.7%) of 431 subjects without AF (p < 0.001).
"Dementia at baseline was much more common in subjects who had clinical stroke than among others (71.2% versus 30.5%)," the investigators report, but dementia prevalence did not differ between those with or without AF.
During follow-up, 100 new dementia cases occurred. Again, the incidence of dementia was statistically the same in those with and without AF, at 16.4% and 18.6%, respectively.
"Clinically diagnosed dementia (at baseline or during the follow-up) was significantly associated with education (OR, 0.89; p = 0.019), beta-amyloid load in the brain (OR, 1.26; p < 0.001), and with vascular pathology (OR, 2.03; p = 0.016), but not with sex, age at death, or APOE e4 allele," Dr. Pirttila's team reports.
They conclude that AF can be considered a contributor to dementia in the very old, through its relation to stroke, but "it is not an independent predictor of dementia."
Stroke 2007;38:1454-1460.
[url]http://www.medscape.com/viewarticle/556327[/url]
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