Statins are not associated with cognitive impairment, dementia, or Alzheimer’s disease

Richardson K, Schoen M, French B, et al. Statins and cognitive function: a systematic review. Ann Intern Med. 2013;159:688-97.

Review questions

In people who do not have cognitive impairment, are statins associated with cognitive impairment or dementia? In people who already have cognitive impairment, are statins associated with worse cognitive performance?

Background

Statins are a class of drugs used to lower cholesterol levels. There is some concern that statins may have side-effects, such as mild cognitive impairment (problems with thinking, memory, language, and judgment that are noticeable but don’t much affect daily living), dementia (cognitive impairment that is serious enough to interfere with daily living), or worsening of cognitive performance.

How the review was done

The researchers did a systematic review, searching for studies published until October 2012.

They found 57 studies and included 3 randomized controlled trials plus 24 studies of other types, with more than 4 million adults.

Key features of the studies were:

• the treatments included atorvastatin (Lipitor®), lovastatin (Altocor®, Altoprev®, Mevacor®), pravastatin(Pravachol®), rosuvastatin (Crestor®), and simvastatin (Zocor®);
• statins were compared with no statin use or placebo; and
• in people without cognitive impairment, the outcomes included new mild cognitive impairment, dementia, and Alzheimer’s disease (the most common cause of dementia); some studies also looked for worse cognitive performance in people with or without cognitive impairment.

What the researchers found

Overall, the quality of evidence was low to moderate.

People without cognitive impairment

Compared with placebo or no statins, statins:

• were not associated with an increased risk of mild cognitive impairment, dementia, or Alzheimer’s disease; and
• were not associated with reduced cognitive performance.

People who already had cognitive impairment

Compared with placebo or no statins, statins were not associated with reduced cognitive performance.

Conclusions

Statins are not associated with cognitive impairment or dementia or with poorer cognitive performance in people who do not have cognitive impairment. In people who already have cognitive impairment, statins are not associated with poorer cognitive performance.

Statins vs placebo or no statins