The International Conference on Alzheimer’s Disease in Hawaii opened this morning with a re-affirmation that in addition to the well known genetic risk factors for dementia, lifestyle factors can have a significant effect in contributing to or decreasing your risk of Alzheimer’s Disease (AD).
I will begin by briefly summarising the genetic knowledge in one paragraph (presumptuous I know).
Dr Jonathan Haines of Vanderbilt University Medical Centre gave a comprehensive review of the genetic literature that emphasised just how much has been achieved in the past ten years. APOE is still the most consistent gene that turns up in all the studies that search for markers for AD. A long list of other genes are turning up in studies of particular populations. The message here is that some genetic changes are particular to families or groups of families and may have to be studied in detail to find the small indications of the genetic changes that are missed in larger studies. The genetic risks are only about 50% known so far but the next ten years should show remarkable progress.
Lifestyle factors include diet, exercise, cognitive stimulation and sleep. It has been common knowledge for the past decade or so that most of these are contributors to many disease conditions including cardiovascular disease, high cholesterol and diabetes and obesity. All of these conditions are in turn factors that can make your risk of Alzheimer’s disease worse.
Dr Kristine Yaffe, of University of California at San Francisco spoke of the importance of mid-life high blood pressure in increasing your risk. She also mentioned diabetes in mid to late life as a risk of dementia due to unstable insulin levels affecting the levels of beta amyloid which has been implicated in the onset of Alzheimer’s Disease. Obesity is increasingly common but she also included in her remarks “overwieght“. This condition can be as harmful as obesity even though the Body Mass Index may not be as high. Fat is not an inert substance but can have toxic effects in the body by causing inflammation. Inflammation is harmful to neurological function. Numerous studies have shown that reducing inflammation by improving immune function can stimulate cognitive function and everyday living. Dr Yaffe remarked that combinations of these factors can increase your risk of AD markedly.
Other factors that can be important in the risk profile for AD include depression. This has been around for a while as a risk for dementia but she clarified that mid-life depression untreated may in fact be a prodrome or early phase of AD. This is a startling way to understand mid-life depression. This is of concern because many people do not seek treatment for their low mood which can then build into depression. This is particularly true of males.
Post-traumatic Stress Disorder (PTSD) is a disruptive condition that is now associated with a raised risk of dementia in veterans up to 2.5 times. The common element in this relationship is that the hippocampus (the brain area mostly responsible for memory decreases in size in PTSD. This also happens in AD but it seems that the shrinkage that occurs in PTSD may increase the risk of it developing into AD.
Sleep is the final are covered by Dr Yaffe. Sleep helps to decrease the levels of beta amyloid , the protein that is associated with AD. Sleep is often disturbed in people with AD. The common disturbance of sleep, sleep apnoea may be associated with hypoxia (deprivation of oxygen) that can contribute to brain injury.
So the message is take care of your brain and your body and you will be more likely to live a healthy old age.
How you live makes a difference. The science is pretty strong now. The areas of your life that influence the presence of high blood pressure, diabetes, obesity/overweight, depression and poor sleep are:
The evidence of other speakers this morning have reinforced the importance of diet. Dr Martha Clare Morris of Rush University Medical Centre, Chicago, reviewed the literature around nutritional factors. These included antioxidants, omega 3 and fish, fats, and Vitamin B12/Folate. You will know from media coverage that when a new discovery is made supporting the use of a particular food to prevent AD, an equally strong study can be quoted to show that this is not so. Dr Morris explained that some of the studies were with subjects who already had adequate dietary levels of these nutritional supplements. Giving them even more showed no effect. The greatest effects have been shown in studies where the subjects have been shown to have inadequate levels of the dietary factor in the first place. Only then does cognitive performance improve or risks decrease. It reaffirmed the importance of the advice that the food supplements we take in such great quantities are really only beneficial when our diets are inadequate in the first place. Eat a healthy balanced diet that is high in antioxidants such as Vitamin E and C, beta carotenes and flavonoides, DHA from fish and other sources and you will maximise your cognitive function and protect your brain into the future.
Exercise, even every second day is effective in reducing your risk of dementia. The size of the hippocampus (remember this is the brain area for memory!) increases with exercise even after 3 months. Exercise also reduces other dementia risk factors such as high blood pressure, obesity, poor sleep and depression. So get out there and buy a pair of trainers and shorts and go for it every second day for at least 45 minutes.
Cognitive skills training is the latest thing to become a popular way of fending off the effects of ageing. What is the evidence? Does it stand up? Yes it does. Dr Sherry Willis, of University of Washington, Seattle, looked at Reasoning, Memory and Speed and asked if cognitive skills training made a difference to actual daily living task such as dressing, eating and toileting.
She found that there was a good effect on reasoning ability, speed of performance and for memory function. For speed she found 86% of people who participated in the cognitive skills training had in improvement in the speed that they could do their tasks while in the control group who had no training only 31% improved. However this improvement does not generalise to other abilities or tasks.
Her study also looked at the effect of a booster session at 1 and 3 years. They found that the booster did improve the effect of the Cognitive Skills Training for both reasoning and speed but not for memory. Lower functioning subjects improved more than higher functioning people.
Of particular interest was her finding that driving skills improved for the group who had Cognitive Skills Training. This may be an important finding for the safety of elderly road users in helping to maintain their driving skills and so their social independence for longer than is currently the case.
Brain plasticity has been in the news a lot in recent years as discoveries of just how much brain change we can expect from aging brains changes by the minute. It is extremely heartening to see such evidence for the usefulness of cognitive skills training in fending off the effects of such conditions as dementia and improving functional abilities for longer so that people who have such a condition are enabled to continue to function with success and confidence long into their futures.