Atrial fibrillation, a common type of erratic heartbeat, can significantly increase a senior's risk for dementia, according to a new study published in the Journal of the American Geriatric Society.

More than 3,000 elderly people participated in the study, reported. Group Health Research Institute scientists looked at seniors who did not have already have dementia or a previous stroke.

The researchers wanted to determine whether atrial fibrillation alone increased a person's risk for dementia and found that the risk rose by as much as 40% to 50% over an average of seven years. According to, a previous British study linked atrial fibrillation to an increased risk for dementia among people who had experienced at least one stroke.

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The researchers suggested that atrial fibrillation could contribute to dementia risk by impeding the delivery of oxygenated blood to the brain, weakening the heart's pumping action and contributing to the formation of blood-clots, among other possibilities.