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The question

Why some people get Alzheimer’s disease and others do not remains largely a mystery. One theory ties high cholesterol to the development of the plaque deposits in the brain that are a hallmark of the memory-destroying disease. In line with that theory, then, might lowering cholesterol levels with statin drugs help prevent Alzheimer’s?

This study

The researchers analyzed data on almost 400,000 older adults, most in their mid-70s, who took a statin and had no signs of Alzheimer’s. In a five-year span, about 2 percent of the women and 1 percent of the men developed Alzheimer’s. Overall, people who took statins regularly were less likely to have developed Alzheimer’s than were those who took them sporadically. This effect was stronger among women (a 15 percent lower risk) than men (12 percent).

The reduction in risk also varied by type of statin and by race or ethnicity. In general, the number of Alzheimer’s diagnoses was higher and statin use lower among black and Hispanic participants than among whites. Among the four statins most commonly used by those in the study, simvastatin (Zocor) lowered risk for white women by 14 percent and for white men by 10 percent; for black women by 22 percent, Hispanic women by 18 percent and Hispanic men by 33 percent. Atorvastatin (Lipitor) lowered risk for white women by 16 percent, black women by 19 percent, Hispanic women by 24 percent and Hispanic men by 39 percent. Rosuvastatin (Crestor) and pravastatin (Pravachol) lowered risk only for white women, by 18 percent. No statin was found to reduce Alzheimer’s risk among black men.

Who may be affected

Older adults with high levels of “bad” (low-density lipoprotein) cholesterol, which increases their chance of developing heart disease and having a heart attack or stroke. The ability of statins to lower LDL cholesterol has made them one of the most-prescribed medications in the United States. Several types of statins are available. According to the researchers, the study findings suggest that “the right type of statin, for the right person, at the right time may provide an inexpensive means to decrease the burden” of Alzheimer’s disease.

Caveats

The analysis did not include comparative data on people who did not take statins.

Find this study

Online Dec. 12 in JAMA Neurology (jamaneurology.com; click “New Online”).

Learn more

Information on Alzheimer’s disease is available at nia.nih.gov/alzheimers. Learn more about statins at fda.gov (search for “cholesterol and statins”).

The research described in Quick Study comes from credible, peer-reviewed journals.