Heart Failure Linked to Dementia Risk
NEW YORK (Reuters Health) – The results of a new study suggest that there is an association between heart failure and an increased risk of dementia or Alzheimer’s disease in the elderly.
Several previous studies have linked heart failure with mental impairment, "but to our knowledge, no investigations have explored the relationship between heart failure and the risk of dementia," Dr. Chengxuan Qiu, of the Karolinska Institute, Stockholm, and colleagues write in the Archives of Internal Medicine.
The researchers therefore examined a community-dwelling group of 1,301 individuals without dementia who were 75 years of age or older. They were evaluated three times over 9 years to identify cases of dementia or Alzheimer’s disease. At the beginning of the study, 205 participants (15.8 percent) had heart failure.
Over the course of the study 440 individuals were diagnosed with dementia, including 333 patients with Alzheimer’s disease. Further analysis of the data revealed an association between heart failure and an 84 percent increased risk of dementia and an 80 percent increased risk of Alzheimer’s disease.
The risk of dementia due to heart failure was lower in patients who were on drugs to reduce high blood pressure, decreasing the risk to 38 percent. Conversely, the risk of dementia in heart failure patients increased as diastolic blood pressure (the bottom number in the blood pressure measurement) dropped below 70 mm Hg, raising the risk by more than three-fold.
The authors suggest that it may be worth looking at possible biological pathways linking heart failure to dementia, specifically to Alzheimer’s disease. The markedly impaired cerebral circulation that results from chronic heart failure, for example, may play a role in the neurodegenerative process, especially in the elderly population. Poor blood circulation in the brain could further promote neurodegeneration by depriving the brain of oxygen, Dr. Qiu’s group notes.
The authors note that blood pressure-lowering drugs may partially counteract the negative effects of heart failure in the brain by improving blood flow and by preventing the formation of obstructions.
SOURCE: Archives of Internal Medicine, May 8, 2006.