Prevention of dementia

Prevention of dementia is the attempt to avoid developing dementia. Although no cure for dementia is available, there are many ways to decrease the risk of acquiring dementia in the first place, including both lifestyle changes and medication.

Lifestyle

Mental activity

"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 the older days. Activities such as reading, playing cards and board games and playing a musical instrument prevent dementia of both Alzheimer's and vascular dementia.^[1] The risk decreases proportionally to the frequency of activity.^[1]

Besides activities during spare time, certain types of occupations may also prevent dementia, especially during the thirties, forties and fifties.^[1] A good job in this case is any mentally demanding one.

Why activity contributes to prevent dementia could be explained by a "brain reserve" built up by the brain: additional connections between neurons are created, connections more resistant to the deterioration seen in dementia.^[1]

Physical activity

Since vascular dementia is the second most common form of dementia (after Alzheimer's disease), decreasing risk factors for cerebrovascular disease also decreases the risk factors for dementia. Thus, physical exercise, having good blood cholesterol, healthy body weight and blood pressure lowers the risk of developing dementia.^[1] An active lifestyle can almost halve the risk compared to a sedentary one.^[1]

The effect of physical activity is not limited to vascular effects. For instance, it can give rise to new neurons in the brain, as well as releasing a substance that can protect them.^[1]

Some studies say Alzheimer's and other dementias may be caused by high blood pressure, since it can cause blood vessel damage by constricting them.^[2][3]

Diet

Obesity increases the risk of any dementia and Alzheimer's disease in particular.^[1] The effect of alcohol on the risk of dementia is a J-shape.^[4] High alcohol consumption increases the risk of dementia^[5] while low alcohol consumption may be protective.^[4] It is not protective however for vascular dementia and overall cognitive decline.^[4] 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. ^[6] The effects of omega-3 fatty acid in the prevention of dementia is uncertain.^[7] Vegetables and nuts may be of benefit,^[1] because of their high content of polyunsaturated fats. Non-fish meat, on the other hand, increases the risk of Alzheimer's,^[1] because of its high content of saturated fat. However, consumption of fish should be limited due to concerns over mercury poisoning, which could exacerbate the symptoms of dementia. Estrogen may also help in the prevention of dementia but cannot help when dementia is already present and when cognitive function is already impaired. It increases cerebral blood flow and is an anti-inflammatory agent, enhancing activity at the neuronal synapses in the brain. It may also help to increase brain activation in regions that are affected by dementia which is mainly the hippocampus region. ^[8] Niacin (vitamin B₃) is also believed to prevent dementia as research shows those who have the highest levels of niacin in their blood, are believed to have the lowest risk of developing dementia or having cognitive decline. Niacin is involved with DNA synthesis and repair and also neural cell signaling, it improves circulation and reduces cholesterol levels. In order for niacin to have a positive effect on the brain, it is recommended that patients have 100 to 300 mg per day. ^[6]

Sleep pattern

Prolonged, more than nine hours, sleep duration (night-time sleep and daytime napping) may be associated with an increased risk of dementia.^[9]

Medication

Hypertension medications

The etiology of vascular dementia includes hypertension, and thus, lowering blood pressure with antihypertensives may have a positive effect in the prevention of dementia, just as physical activity.

However, a study failed to demonstrate a link between high blood pressure and developing dementia. The study, published in the Lancet Neurology journal July 2008, found that blood pressure lowering medication did not reduce the incidence of dementia to a statistically significant degree. A prospective meta-analysis of the data from this study with other studies suggested that further research might be warranted. ^[10]

Anti-diabetic drugs

Diabetes mellitus is a risk factor for vascular dementia, and is thus lowered with anti-diabetic drugs.^[11]

Besides, Rosiglitazone (Avandia) improves memory and thinking ability to people with mild Alzheimer's disease. The mechanism of the effect might be due to the ability of the drug to reduce insulin resistance.^[1] Thus, less insulin needs to be released to achieve its metabolic effects. Insulin in the bloodstream is a trigger of amyloid beta-production,^[11] so decreased insulin levels decrease the level of amyloid beta. This leads to less formation of amyloid plaques seen in Alzheimer's disease.

NSAIDs

Non-steroidal anti-inflammatory drugs (NSAIDs) can decrease the risk of developing Alzheimer's and Parkinson's diseases.^[1] The length of time needed to prevent dementia varies, but in most studies it is usually between 2 and 10 years.^{[12][13][14][15][16]} Research has also shown that it must be used in clinically relevant dosages and that so called "baby aspirin" doses are ineffective at preventing and treating dementia.^[17]

Alzheimer's disease causes inflammation in the neurons by its deposits of amyloid beta peptides and neurofibrillary tangles. These deposits irritate the body by causing a release of e.g. cytokines and acute phase proteins, leading to inflammation. When these substances accumulate over years they contribute to the effects of Alzheimer's.^[18] NSAIDs inhibit the formation of such inflammatory substances, and prevent the deteriorating effects.^[19][20][21]

Vaccine

There is yet no vaccine against dementia.^[1] Such a vaccine could activate the body's own immune system to combat the beta amyloid plaques in Alzheimer's disease. One problem to overcome is overreaction from the immune system, leading to encephalitis.^[1]

See also

• Dementia
• Alzheimer's disease
• Preventive medicine
• Alcohol dementia

References

1. ^ ^{a b c d e f g h i j k l m n} Thoenen, Eugenia; Health Statistics Center Statistical Staff; Doria, James; King, Fred; Leonard, Thomas N.; Light, Tom; Simmons, Philip (February 2005). "Prevention of Dementia". Dementia: The Growing Crisis in West Virginia. http://www.wvdhhr.org/bph/oehp/hsc/dementia/prevent.htm. Retrieved 2 October 2009. 
2. ^ "Blood pressure drug dementia hope". BBC News. 28 July 2008. http://news.bbc.co.uk/1/hi/health/7528539.stm. Retrieved 2 October 2009. 
3. ^ "Blood Pressure Drugs May Protect Against Alzheimer's" (Press release). Boston University School of Medicine. 27 July 2008. http://www.washingtonpost.com/wp-dyn/content/article/2008/07/27/AR2008072701213.html. Retrieved 2 October 2009. 
4. ^ ^{a b c} Chen JH, Lin KP, Chen YC (October 2009). "Risk factors for dementia". J. Formos. Med. Assoc. 108 (10): 754–64. doi:10.1016/S0929-6646(09)60402-2. PMID 19864195. 
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6. ^ ^{a b} Robert, Levine (2006). "Defying dementia: understanding and preventing Alzheimer's and related disorders". Westport: conn: Praeger. 
7. ^ Cederholm T, Palmblad J (March 2010). "Are omega-3 fatty acids options for prevention and treatment of cognitive decline and dementia?". Curr Opin Clin Nutr Metab Care 13 (2): 150–5. doi:10.1097/MCO.0b013e328335c40b. PMID 20019606. 
8. ^ Eileen M., Welsh (2003). "Focus on Alzheimer's disease research". Nova Biomedical books: 699. 
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10. ^ Hyvet, investigators; Burch; Fletcher; Bulpitt (August 2008). "Incident dementia and blood pressure lowering in the Hypertension in the Very Elderly Trial cognitive function assessment (HYVET-COG): a double-blind, placebo controlled trial". Lancet Neurol 7 (8): 683–9. doi:10.1016/S1474-4422(08)70143-1. PMID 18614402. 
11. ^ ^{a b} "Diabetes and Alzheimer's linked" (Press release). Mayo Clinic. 6 November 2008. http://www.mayoclinic.com/health/diabetes-and-alzheimers/AZ00050. Retrieved 2 October 2009. 
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