Prevention

Statins. Statins are common drugs used to lower cholesterol levels. In past years, a number of studies reported a significantly lower risk for Alzheimer's disease in patients who took statins. However, newer studies have failed to prove that statins can help prevent Alzheimer's disease. In these recent studies, large numbers of elderly people had their dementia evaluated at baseline and then monitored over several years. The results indicated that statin use did not predict onset of AD.  In the meantime, the NIH is conducting a clinical trial to investigate whether simvastatin can slow the progression of AD.

Male and Female Hormone Replacement Therapies

Hormone Replacement Therapy. Hormone replacement therapy (HRT) has been studied for years for health effects after menopause, including its effect on mental decline. A number of studies, including a major 2003 analysis, have found no differences in mental performance and no protection from Alzheimer's disease in women taking HRT compared to non-users. The 2003 trial, called the Women's Health Initiative Memory Study (WHIMS), enrolled 4,500 women over 65 years of age. The WHIMS study showed that older postmenopausal women who took combination HRT (estrogen plus progestin) had twice the risk of developing dementia than similarly aged women who received placebo pills. In addition to increasing the risk for dementia, (including Alzheimer's disease), combination HRT failed to prevent the development of mild cognitive impairment. Based on these results, the researchers from the National Institute on Aging (NIA) recommended against prescribing combination hormone therapy to older women for maintaining or improving cognitive function. The NIA continued to research whether estrogen-only therapy could prevent or delay the onset of Alzheimer's disease. Results released in 2004 indicated that women ages 65 years and older who took estrogen-only HRT had a slightly increased risk of developing dementia.

Testosterone. Some testosterone converts to estrogen, which may be why older men appear to have a lower risk for Alzheimer's disease than older women. Animal studies have suggested that testosterone may help reduce levels of beta amyloid. There is also some evidence that low testosterone levels may be a particular risk factor in men with the APOE4 gene. Some experts believe that giving testosterone to elderly men and combinations of testosterone and estrogen to older women may prove to be protective. Side effects of testosterone in women include increased body hair, acne, fluid retention, anxiety, and depression. Long term benefits or serious adverse effects are unknown.