Monday, April 30, 2012
Ten Steps to Reduce Your Risk of Alzheimer's Disease
Prevention is an important topic in AD as effective treatments are yet to be discovered. Although several AD drugs are available, these agents appear only to slow progression rather than reverse or cure the disorder.
Genetic factors play a key role in risk for AD. However, environmental and behavioral factors also contribute to risk and are modifiable.
Identifiable risk factors are known for AD. The U.S. Agency for Healthcare Research and Quality has recently published a comprehensive summary of the risk factors in AD and cognitive decline. A second recent review suggests that population-based prevention strategies may reduce the rates of AD by up to 25%. Links to these two references and a summary of prevention research at the Alzheimer's Association website are listed at the bottom of this post.
Based on what we currently know, I will outline ten steps individuals might consider in their own personal lives to reduce their risk of AD.
1. Build and maintain cognitive reserve. Cognitive decline occurs with the aging process. AD represents a specific more rapid decline in memory and other cognitive functions with age. Several studies demonstrate the protective effect of early cognitive development and lifelong engagement in intellectual stimulation. By "banking" a high level of cognitive reserve, individuals may prolong the period of time they function at a higher level.
2. Engage in vigorous exercise on a regular basis. Aerobic exercise appears to contribute to prolonged brain vascular health. Vascular factors appear to contribute to components of cognitive decline and AD. Aerobic exercise for 30 minutes a day on most days of the week may reduce or delay the risk for AD.
3. Protect against risk for traumatic brain injury. Traumatic brain injury can result in an increased risk for later AD. This effect may be primarily found in men as some studies fail to find an association in women with traumatic brain injury. The best interventions for reducing risk of traumatic brain injury include reducing exposure to high risk activities (i.e. football), wearing protective helmets when biking or riding a motorcycle, using seat belts in automobiles and driving automobiles with advanced airbag technology and safety design.
4. Don't smoke cigarettes. Regular heavy smoking increases risk for brain vascular abnormalities including stroke and AD. If you smoke quit. If you don't smoke, don't start. Smoking cessations options are increasing and past failed attempts should not discourage additional cessation attempts.
5. Maintain a normal body weight. Recent research studies are finding increased AD in individuals with obesity. The mechanism for this association is unclear, but may be related to the effects of obesity on vascular health, insulin function or a link to systemic inflammation. Reduce your weight if your are overweight. If you are in the normal weight range, maintain this weight over your lifespan.
6. Consider the Mediterranean diet. The Mediterranean diet appears to reduce the rate of cognitive decline with age and may reduce risk of developing AD. This diet is high in content of fruits and vegetables with reduced consumption of red meat and full fat dairy products. Limited alcohol consumption also is included in the diet. High consumption of foods with protective omega three fatty acids may contribute to the diet's effect on cognitive function. I have previously posted on the potential benefits of the Mediterranean diet here and here.
7. Maintain normal serum cholesterol and lipids. High serum cholesterol appears to affect the brain as well as the heart. There is some evidence the use of cholesterol lowering agents such as statins may reduce the process of amyloid development in the brain--a key pathological feature in AD.
8. Treat depression if it is present. Depression is also a brain disease and appears to be associated with an increased risk for later AD. It is unclear whether late-onset depression is a possible symptom of early AD or whether depression specifically leads to an increased AD risk. Depression may contribute to behaviors that increase AD risk, i.e. higher smoking rates and reduced physical activity. Treatment of depression may reduce symptoms of depression as well as reduce risk of later AD.
9. Treat diabetes if it is present. The potential role of insulin in AD is receiving increased research attention. Insulin resistance, a common feature of diabetes, appears to have a variety of deleterious effects on the brain and brain vasculature. Early identification and treatment of diabetes (both type I and type II) may reduce risk for AD.
10. Build and maintain social support and social engagement. Social factors appear to contribute to the risk of AD. AD rates are higher in unmarried individuals living alone. Social interaction may be a cognitive enhancing activity that promotes learning and general cognitive engagement. Friends and family can challenge individuals to maintain intellectual interaction and stimulation.
Definitive prospective research clinical trials linking these ten interventions to reduced AD risk are limited or non-existent. Association research studies cannot prove causality. Nevertheless, these ten steps are generally consistent with leading a healthy lifestyle. The chance that they may also reduce AD risk should provide added incentive for
Photo of a macaw from the Palm Beach Zoo from the author's files.
Alzheimer's Association Prevention Website
Agency for Healthcare Research and Quality Report on Preventing Alzheimer's Disease and Cognitive Decline
Barnes DE, & Yaffe K (2011). The projected effect of risk factor reduction on Alzheimer's disease prevalence. Lancet neurology, 10 (9), 819-28 PMID: 21775213