By Chris Cunningham

NEW YORK, Sep 08 (Reuters Health) - Drugs that reduce the risk of arterial diseases, such as those that lower blood pressure, reduce blood cholesterol levels, prevent dangerous blood clots, and treat diabetes, may also help to reduce the risk of dementia in older adults, according to a study in the September issue of the Journal of American Geriatrics Society.

By reducing the risk of arterial disease, these medications help to maintain blood flow to the brain. This appears to cut the risk of intellectual impairment in the elderly, including the risk of Alzheimer's disease, according to the report.

"There is growing evidence that cerebrovascular disease may contribute to the development, progression and presentation of Alzheimer's disease," Dr. Hugh C. Hendrie, of the Indiana University School of Medicine, told Reuters Health.

In a random sample of 2,212 African-Americans aged 65 and older, Hendrie and his colleagues found that a wide range of drugs for lowering blood pressure and cholesterol; managing diabetes; and thinning blood reduced the risk of mental impairment by more than 25%.

"The vascular risk factor-mediating medications, when examined together (antihypertensives, antidiabetics, antihyperlipidemics and antithrombotics), were associated with a significantly reduced risk of cognitive impairment after controlling for age, education and stroke," Hendrie and his team write.

But when they looked at each of these drugs separately, Hendries explained, the study authors found that antihypertensives or blood pressure medications showed the greatest ability to protect mental capabilities such as memory, reasoning and judgment.

The interviewers asked participants questions to determine if dementia was present, asking for example, if they knew the date and where they were. They also asked family members about the participants' ability to function, and later performed extensive clinical assessments in the participants' homes.

Although there is much evidence supporting the need for aggressive treatment of hypertension among the middle aged, Hendrie pointed out that treating the elderly has been more controversial because their blood pressure tends to be particularly volatile. Lowering blood pressure too much also can be dangerous, he said, creating a condition known as hypotension, which causes symptoms such as dizziness and fainting.

The exceptions to their findings were certain blood pressure drugs that are "centrally acting" or those that act on the central nervous system, which the authors found more than doubled the risk of intellectual impairment, and possibly even increased mental deterioration.

In cerebrovascular disease, one of the primary causes for impairment in mental processes in older adults, arterial disease interferes with the blood supply to the brain. High blood pressure, diabetes and high cholesterol are all risk factors for cerebrovascular disease. Older African-Americans are at very high risk for cerebrovascular disease, Hendrie said, which also puts them at high risk for dementia.

"If the brain has vascular disease as well as Alzheimer's disease, the cognitive function will be much worse," Hendrie pointed out. "What we are looking for are preventable risk factors."

The authors admitted that the study does not show whether the effects on mental functioning were the direct result of effects from the medications or the result of other factors that can contribute to how well a person functions.

"For example, older people who visit doctors and take medications may also adhere to a healthier diet," they point out. "It is possible that cognitively impaired or demented individuals underutilize medical services."

The research team plans to conduct more studies to examine the long-term effects of these drugs.

(From Reuters Health)