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Research has revealed a number of factors that may be able to prevent or delay the onset of dementia in some people. Regular exercise, such as brisk walking, is one of the most important factors for preventing dementia in people who are currently normal, or for slowing the decline in people who are already impaired. The exact amount or type of exercise is not clearly defined, and patients with heart disease, joint problems, or other conditions should obtain a doctor’s advice on an exercise regimen that is safe for them.
Other lifestyle factors may also prevent dementia. For example, studies have shown that people who maintain tight control over their glucose levels tend to score better on tests of cognitive function than those with poorly controlled diabetes.
Several studies also have suggested that people who engage in intellectually stimulating activities, such as social interactions, chess, crossword puzzles, and playing a musical instrument, significantly lower their risk of developing Alzheimer's disease and other forms of dementia. Scientists believe mental activities may stimulate the brain in a way that increases the person's "cognitive reserve"—the ability to cope with or compensate for the pathologic changes associated with dementia.
Researchers are studying other steps people can take that may help prevent Alzheimer's disease in some cases. So far, none of these factors has been definitively proven to make a difference in the risk of developing the disease. Moreover, most of the studies addressed only Alzheimer's disease, and the results may or may not apply to other forms of dementia.
Nevertheless, scientists are encouraged by the results of these early studies and many believe it will eventually become possible to prevent some forms of dementia. Possible preventive actions include:
Exercise. Regular exercise stimulates production of chemicals called growth factors that help neurons survive and adapt to new situations. These gains may help to delay the onset of dementia symptoms. Exercise also may reduce the risk of brain damage from atherosclerosis. A study has shown that exercise helps increase the size of the hippocampus, the part of the brain that helps us form memories.
Sleep. Greater than six hours of sleep can decrease the amount of amyloid burden in the brain, which is present in Alzheimer's disease. Sleep helps consolidate memories.
Social interaction and intellectual stimulation. Increasing social interaction and intellectual stimulation can stimulate the mind and slow cognitive decline.
Education. Researchers have found evidence that formal education may help protect people against the effects of Alzheimer's disease. In one study, researchers found that people with more years of formal education had relatively less mental decline than people with less schooling, regardless of the number of amyloid plaques and neurofibrillary tangles each person had in his or her brain. The researchers think education may cause the brain to develop robust nerve cell networks that can help compensate for the cell damage caused by Alzheimer's disease.
Lowering homocysteine. In one study, elevated blood levels of the amino acid homocysteine were associated with a 2.9 times greater risk of Alzheimer's disease and a 4.9 times greater risk of vascular dementia.
A preliminary study has shown that high doses of three B vitamins that help lower homocysteine levels - folic acid, B12, and B6 - appear to slow the progression of Alzheimer's disease. Researchers are conducting a multi-center clinical trial to test this effect in a larger group of patients.
Lowering cholesterol levels. Research has suggested that people with high cholesterol levels have an increased risk of developing Alzheimer's disease. Cholesterol is involved in formationof amyloid plaques in the brain.
Mutations in a gene called CYP46 and the ApoE E4 gene variant, both of which have been linked to an increased risk of Alzheimer's disease, are also involved in cholesterol metabolism. Several studies have also found that the use of drugs called statins, which lower cholesterol levels, is associated with a lower likelihood of cognitive impairment.
Lowering blood pressure. Several studies have shown that antihypertensive medicine reduces the odds of cognitive impairment in elderly people with high blood pressure. One large European study found a 55 percent lower risk of dementia in people over 60 who received drug treatment for hypertension. These people had a reduced risk of both Alzheimer's disease and vascular dementia.
Controlling inflammation. Many studies have suggested that inflammation may contribute to Alzheimer's disease. Moreover, autopsies of people who died with Alzheimer's disease have shown widespread inflammation in the brain that appeared to be caused by the accumulation of beta amyloid.
Another study found that men with high levels of C-reactive protein, a general marker of inflammation, had a significantly increased risk of Alzheimer's disease and other kinds of dementia.
Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. As a Stanford Health Care patient, you may have access to the latest, advanced clinical trials.
Open trials refer to studies currently accepting participants. Closed trials are not currently enrolling, but may open in the future.