About two-thirds of dementia cases are caused by Alzheimer’s. The next most common form is vascular dementia, which is caused by deterioration of the brain’s blood vessels and often involving minor strokes. There are some other subtypes and an increasing belief that dementia at very old ages typically involves different forms of disease. Good news about Alzheimer’s and dementia. How can this be? Well, according to research1 reported in the New Scientist, there is some good news.
The good news comes from two studies published in the medical journal, The Lancet. One study compared two surveys of dementia numbers in the United Kingdom done 20 years apart. A 1994 study led to the conclusion that there were about 650,000 people with the condition. Given the increase in average age of the population over the intervening years, using exactly the same tests and definitions, should have found 900,000 people dementia, but the count came up over 200,000 people short.
The other study examined the health of two groups of Danish people in their mid-90s, born a decade apart in 1905 and 1915. Although the two groups had similar physical health, those born in 1915 markedly outperformed the earlier group in cognitive tests. This second group was not stronger, but they were smarter.
So how can this be? The conjecture is that long term trends of rising prosperity, education, and better health are good for the brain. Special attention should be paid to higher education levels. They support the notion of a cognitive reserve that keeps the brain functioning at a high level despite mild physical deterioration.
These results, while good, should not be misinterpreted. Alzheimer’s and dementia still represent significant threats that need to be addressed. The good news is a relative one. That is, matters are not as bad as they were thought to be, but they are still pretty bad.
Moreover, the conjecture as to why there has been this improvement, points to activities and practices advocated by the healthymemory blog. Good physical health and diet are definitely important. The recommended diet is the heart healthy, or Mediterranean diet, rich in fruit and vegetables, with plenty of fish and not too much red meat or high calorie junk food. An unfortunate trend which is working against this good trend is the increase in obesity with the concomitant increase in diabetes. Some have spoken of Alzheimer’s as being a form of brain diabetes.
It should be understood that formal education is not required to build a cognitive reserve. An effort to grow the mind continually by having new experiences, learning new things through reading, technology and by interacting with fellow humans all serve to build a cognitive reserve. The healthymemory blog is dedicated to these activities.
1Drew, L. (2014). Down with dementia. New Scientist, 11 january, 32-35.
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