A well-established concept in Alzheimer's disease research is cognitive reserve. For whatever reason, people with more education are less likely to develop Alzheimer's disease. They call it "cognitive reserve," suggesting that a better educated brain has something in reserve to compensate for the deterioration that comes with disease. This isn't by way of storing up information, but rather the process of learning causes changes in the structure of the brain that strengthen it.
We discussed cognitive reserve in Beating the Dementia Monster, pairing education with intellectually stimulating occupations. We left the question open as to whether this reflected a) learning activities strengthening the brain, b) a likely higher IQ among the better educated, or c) better education leading to more stimulating occupations. So part of the question is, were you simply born with that reserve (nature), or did it develop as a consequence of life experiences (nurture)? If life experiences, was that due to learning activities when you were younger or to a mentally stimulating career?
The question of why education would correlate with cognitive reserve has been investigated in the United States and in some other countries where most of the population is better educated. My sense is that the evolving consensus is that the mental activities associated with learning build cognitive reserve. But the question is still open regarding the role of the mentally stimulating occupations better-educated people are likely to occupy. Would doing this research in a population biased toward lower education reveal anything different from the research conducted in generally well-educated countries?
I came across an interesting article in the November issue of Alzheimer's and Dementia; the journal of the Alzheimer's Association. It was entitled, "Education, but not occupation, is associated with cognitive impairment: The role of cognitive reserve in a sample from a low-to-middle-income country." I don't subscribe to Alzheimer's and Dementia, so I had to infer the content of the research from the abstract.
From the title of the article, we see the researchers concluded that the activity of learning contributed to the development of cognitive reserve. Stimulating occupation ... not so much.
So, in what country did they do the research? The abstract didn't say, but the researchers were from Brazil. So I'm guessing that's where they did their work. The researchers studied mental capacity of 1,023 subjects. Seventy-seven per cent had less than five years of education, and 56% were in unskilled occupations. They found that occupation complexity and demands were unrelated to cognition.
They concluded that, "Education, but not occupation, was related to better cognitive abilities independent of the presence of neuropathological insults." They used the established "Clinical Dementia Rating Scale" to relate their findings to what would likely be the presence or absence of neurodegenerative disease.
I'm left wondering a bit as to whether they tied all of the pieces together to get to their conclusions. Do their results establish a distinctive relationships between learning and occupation in the context of disease? I'm not so sure. But it does appear that they have reinforced the belief that educating people, especially young people, builds resistance to Alzheimer's disease.
I wonder, too, whether the role of physical activity in different occupations might mitigate some of the differences in cognitive challenge. It strikes me that the professional sort of work often associated with higher levels of education often involves a lot more sitting than other types of work.
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