Prevention of dementia

The aim of dementia prevention is to delay or prevent dementia. Dementia prevention is a global health priority and as such requires a global response. Recent initiatives include the establishment of the International Research Network on Dementia Prevention (IRNDP) which aims to link researchers in this field globally, and the establishment of the Global Dementia Observatory a web-based data knowledge and exchange platform, which will collate and disseminate key dementia data from members states. Although there is no cure for dementia currently, it is well established that modifiable risk factors influence both the likelihood of developing dementia and the age at which it is developed. Dementia can be prevented by reducing the risk factors for vascular disease (e.g. diabetes, high blood pressure, obesity, smoking, and physical inactivity) and depression. Livingstone et al. (2014) conclude that more than a third dementia cases are theoretically preventable. Among older adults both an unfavorable lifestyle and high genetic risk are independently associated with higher dementia risk. A favorable lifestyle is associated with a lower dementia risk, regardless of genetic risk. 'Use it or lose it' might be applied to the brain when it comes to dementia. Intellectual activities help keep the mind in shape in later years. Activities such as reading, learning a new language, playing cards and board games and playing a musical instrument can postpone the onset and slow the progression of both Alzheimer's and vascular dementia. The risk decrease is proportional to frequency of activity, with slower cognitive decline being associated with both late-life and early-life increased cognitive activity. Apart from spare time activities, a mentally demanding job may prevent dementia, especially during the thirties, forties and fifties. Mental activity may help to prevent dementia by building up a 'brain reserve': additional connections between neurons are created which are more resistant to the deterioration seen in dementia. Since vascular dementia is the second most common form of dementia (after Alzheimer's disease), reducing the risk of cerebrovascular disease also reduces the risk of dementia. Thus, physical exercise, having good blood cholesterol, healthy body weight and blood pressure lowers the risk of developing dementia. An active lifestyle can almost halve the risk compared to a sedentary one. Results of one meta-analysis, which investigated the relationship between physical activity and risk of cognitive decline in people without dementia, showed exercise had a significant and consistent protective effect against cognitive decline, with high levels of physical activity being most protective. Another meta-analysis showed that not only did aerobic exercise reduce the risk of dementia but it may also slow cognitive decline in those with dementia. The effect of physical activity is not limited to vascular effects. Physical activity can give rise to new neurons in the brain, as well as releasing a substance that can protect them. The protein known as brain-derived neurotrophic factor (BDNF) is known to be important in the development, survival and plasticity of neurons. Regular exercise can boost BDNF levels by 2–3 times. Obesity increases the risk of any dementia and Alzheimer's disease in particular. The effect of alcohol on the risk of dementia is a J curve: high alcohol consumption increases the risk of dementia while low alcohol consumption may be protective. However, low alcohol consumption may not protect against vascular dementia and overall cognitive decline. Moderate alcohol consumption can possibly reduce the risk of vascular disease and dementia because it can increase blood levels of HDL cholesterol and weakens blood-clotting agents such as fibrinogen, which offers some protection against heart attacks and small subclinical strokes that together can ultimately damage the brain.