Research and Development News

Atrial Fibrillation Linked to Increased Risk of Dementia

By: David Elliot | Thursday 22 April 2010 04:04 PDT

A recent medical study determined that there is a connection between chronic heart disease, such as atrial fibrillation, and an increased risk of acquiring dementia, such as Alzheimer's, in later years. The long-term presence of an abnormal heart rhythm, the defining characteristic of atrial fibrillation, also correlated with dementia patients at higher risk of death.

Heart Disease as Causative Factor
Researchers postulated that dementia, of which Alzheimer's is the most common form, could be caused directly by early vascular disease. Patients with an abnormal heart rhythm condition have proven to be more likely to experience heart failure, which in turn may negatively affect cerebral functions.

It has also been established that a series of minor strokes, associated with the presence of atrial fibrillation, causes early cognitive declines in which the brain loses its capacity to function at previous levels.

Age and Dementia
Age remains the strongest dementia risk factor, shown in a community-based study which demonstrated the increased incidence with time:

• Ages 65 to 69 years - 0.6 percent
• Ages 70 to 74 years - 1.0 percent
• Ages 75 to 79 years - 2.0 percent
• Ages 80 to 84 years - 3.3 percent
• Ages 85 years and older - 8.4 percent
  

According to the researchers, the risk of acquiring atrial fibrillation also increased in concert with age. This observation led to speculation that both dementia and an abnormal heart rhythm may both have their roots in the early presence of vascular disease.

Study Methodology
Researchers gleaned the information for the study from a large health care database of 37,026 patients who had an average of five years of follow-up in the Intermountain Healthcare system, located in Utah. Persons with pre-existing dementia or atrial fibrillation conditions were excluded.

Of the patients studied, 27 percent developed atrial fibrillation and 4.1 percent acquired dementia within the five-year period. Noted limitations included the individualized treatment of patients, which may have had a direct effect on morbidity and mortality rates, among other factors.

Researchers concluded that atrial fibrillation was independently associated with all forms of dementia, and also with those at higher risk of death. The study thus emphasized the importance of detecting and treating vascular diseases at younger ages, as a control mechanism to prevent the development of conditions like Alzheimer's in later years.