Prevention of dementia
From these risk and protective factors some recommendations regarding lifestyle and health behaviour appear plausible:
- Have good social ties with a number of confidants
- Have many diverse (= physical, mental and social) leisure activities.
- Have physical activity (three times a week or more, like walking, gardening, sports...)
- Eat a mediterranean diet
- Eat fruit and vegetables regularly
- Eat fatty fish at least once a week
- Do cognitive training whilst still healthy
- Have challenging work and cognitive activity
- Avoid heavy drinking, as well as binge drinking or alcohol abuse and addiction
- Avoid being overweight
- Avoid central obesity
- Avoid hypercholesterinamia
- Reduce saturated fat intake
- Avoid getting type 2 diabetes
- Avoid high blood pressure in mid life
- Avoid smoking
- Prevent depression
- Avoid working with pesticides
Intervention studies – rational and challenges
However, even if such recommendations appear plausible and substantiated by the epidemiological data, randomised controlled intervention trials (RCTs) are the gold standard and are required to prove the effect of an intervention aiming at these risk factors. The multifactorial and heterogeneous character of AD allows multiple prevention approaches, but its long preclinical phase makes prevention trials challenging. As many persons are affected, relatively small effects of an integrative intervention on common risk factors may have a huge impact on public health. Intervention studies integrating several different approaches have not been done for AD so far, and disappointing results of previous trials with single agents in elderly or already cognitively impaired persons (e.g. the Women Health Initiative Study with estrogen, NSAID trial, vitamin E in mild cognitive impairment (MCI) trial) point out some key issues:
- timing – starting earlier may lead to better effects;
- target group – a healthy, too young population will require very long follow-up times;
- large sample sizes and considerable financial resources;
- appropriate outcome measures - cognitive impairment may be better than ‘conversion’ to dementia.
Ethical issues need also to be carefully considered, since placebo-controlled trials for high BP or cholesterol are not possible because such treatments are known to protect against cardio/ cerebrovascular diseases (e.g. Syst-Eur). These issues and need for preventive trials were also highlighted in the recent Guidelines for AD and other dementias by the European Medicines Agency (EMEA) (http://www.emea.europa.eu).
Carefully designed and monitored RCTs are thus needed to clarify to what extent intervention will delay cognitive impairment among people with an increased dementia risk. These data will have a great scientific value and will be needed for health education and community planning.
Last Updated: Thursday 08 October 2009