Clinical Question

Do statins prevent dementia or cognitive decline?

Evidence-Based Answer

Statins given in later life to patients at risk of vascular disease do not prevent dementia or cognitive decline compared with placebo. Adverse effects are similar between groups.¹ (Strength of Recommendation: A, based on consistent, good-quality patient-oriented evidence.)

Practice Pointers

In 2015, the prevalence of dementia in the U.S. population older than 65 years was approximately 11%. The estimated worldwide cost of dementia will reach $1 trillion by 2018; thus, prevention strategies are critical.² There is a close association between dementia and cardiovascular disease, and because statins have secondary preventive effects for cardiovascular disease,³ it has been posited that they may also help prevent dementia. Several observational studies have reported a slight benefit for statin use in the prevention of dementia.^4–6 This Cochrane review addressed whether statins are effective for the primary prevention of dementia or cognitive decline.¹

The authors of this review examined two randomized controlled trials with 26,340 participants 40 to 82 years of age, including 11,610 persons 70 years or older.¹ One trial compared simvastatin (Zocor) with placebo over five years; the other compared pravastatin (Pravachol) with placebo over 3.2 years. All of the participants in both study populations had a moderate to high vascular risk. The cognitive assessments used in these two studies were heterogeneous and had different end points, including changes in performance on the Mini-Mental State Examination (which is copyright restricted and requires a fee for the form and administering the test), the Stroop Color and Word Test, and the Picture-Word Learning test, among others.

There were no differences in the number of patients who developed dementia or cognitive decline between those taking statins or placebo. Although both studies evaluated cognitive decline, only the simvastatin study examined the incidence of dementia. Among the 20,536 participants in the simvastatin study who were randomized to treatment or placebo, 31 new cases of dementia developed in each arm of the study. Both studies were at low risk of bias, and there were no differences in the number of adverse effects leading to discontinuation.

An analysis from the Agency for Health-care Research and Quality cites the availability of only low-quality, discordant evidence to link statin use and prevention of cognitive decline.⁷ In its most recent clinical guideline, the American Academy of Neurology does not address statin use to prevent dementia.⁸

The practice recommendations in this activity are available at http://www.cochrane.org.

The opinions and assertions herein are those of the authors, and should not be construed as official or as those of the Department of the Air Force, the Department of the Navy, the Uniformed Services University of the Health Sciences, or the Department of Defense.