Key messages from scientific research that's ready to be acted on
Got It, Hide thisFink HA, Jutkowitz E, McCarten JR, et al. Pharmacologic Interventions to Prevent Cognitive Decline, Mild Cognitive Impairment, and Clinical Alzheimer-Type Dementia: A Systematic Review. Ann Intern Med. 2018;168:39-51.
In people with normal cognition or mild cognitive impairment, can drug treatment prevent or delay loss of cognitive function (e.g., thinking, learning, remembering) or dementia?
Cognitive function includes abilities such as thinking, remembering, using language, and making decisions. As we get older, our cognitive functions may decline. Mild cognitive impairment includes cognitive changes that are noticeable but usually don’t have much effect on daily living. Dementia is cognitive impairment that is serious enough to interfere with daily living.
Some drugs have been used to try to prevent or delay cognitive decline. However, we don’t know which drugs, if any, are effective. This review focused on drugs to prevent or delay dementia either due to Alzheimer disease or to unknown causes. Dementia due to repeated strokes was not included.
Researchers in the USA did a systematic review of studies available up to July 2017. They analyzed 51 studies of moderate or good quality. Most studies were randomized controlled trials.
Key features of the studies were:
Most of the evidence was of low strength (confidence in results was limited) or insufficient to reach any conclusions.
We have mainly reported results for dementia and mild cognitive impairment outcomes here. If that information wasn’t available, we reported results for cognitive function tests. We have not reported results with insufficient evidence.
Results in adults with normal cognition (all low-strength evidence)
Compared with placebo (also see Table below):
In drug vs drug comparisons:
Results in adults with mild cognitive impairment (all low-strength evidence)
Compared with placebo:
In people with normal cognition or mild cognitive impairment, drug treatments don’t prevent dementia or delay loss of cognitive function.
Drugs | Number of studies and people | Effect of drugs | Strength of evidence* |
Antihypertension drugs | 4 studies (21,831 people) | Did not prevent dementia at 2 to 4 years | Low |
| 1 study (5,926 people) | Did not prevent new cognitive impairment at 5 years | Low |
Aspirin (NSAID) | 1 study (6,377 people) | Did not improve performance on cognitive function tests at 10 years | Low |
Other NSAIDs | 1 study (2,117 people) | Did not prevent dementia at 8 years | Low |
Estrogen | 1 study (2,947 people) | Increased risk for dementia or mild cognitive impairment at 5 years | Low |
Estrogen plus progestin | 1 study (4,532 people) | Increased risk for dementia but not mild cognitive impairment at 4 years | Low |
Raloxifene | 1 study (5,386 people) | Decreased risk for mild cognitive impairment but not dementia at 3 years at a dose of 120 mg/day | Low |