Primary and secondary prevention interventions for cognitive decline and dementia - An overview

Dementia is a syndrome characterised by deterioration in memory, thinking, behaviour, and the ability to perform everyday activities, which ultimately may lead to total dependence and death. Since the world’s population is steadily growing older, the number of people with dementia is also increasing. It is therefore of utmost importance to identify effective strategies to prevent or delay its onset.The key findings of this overview of reviews are based on evidence from eight systematic reviews. The results for the single interventions targeting cognitively healthy people suggest that compared to controls: Antihypertensive drugs may lead to a slight decrease in incidence of dementia in people with hypertension (low certainty of evidence). Statin therapy probably leads to little or no difference on incidence of dementia in people with, or at risk of, cardiovascular disease (moderate certainty). Omega-3 Fatty Acids (FAs) probably lead to little or no effect on cognitive test scores (moderate to high certainty). Computerised cognitive training probably leads to a slight improvement in cognitive test scores directly after the training (moderate certainty). Aerobic exercise may lead to little or no effect on cognitive test scores (low certainty). The results for the interventions targeting people with mild cognitive impairment suggest that compared to control: Cholinesterase inhibitors probably lead to a slight decrease in dementia incidence, but to significantly more adverse events (moderate certainty). Vitamin E probably leads to little or no difference in incidence of Alzheimer’s dementia (moderate certainty). Omega-3 FAs probably lead to little or no difference in cognitive test scores (moderate to high certainty). We did not find any reviews that evaluated the effects of interventions targeting more than one risk factor, and we can therefore not say anything about the combined effects of these interventions.