Preventing dementia: the promising, the disappointing and the inconclusive

What’s proven to prevent the development of dementia after the age of 80?

Not brain training, not medication, not regular exercise, not a healthier diet and not a busy social calendar, according to a series of reports published Monday.

But ask the question a bit differently, and the answer is not quite as discouraging: What should you be doing anyway right now that might delay or prevent the development of dementia late in life?

Some combination of all of the above.

Most of us hope to live well into old age, and doing so with our marbles intact is typically a condition we attach to that wish. But half or more of Americans over the age of 90 will be beset with some type of dementia, and 1 in 10 people age 65 and older has Alzheimer’s disease.

Scientific research, in its highest and most rigorous form, has done little to illuminate a single path to prevent or forestal dementia and cognitive decline. That grim conclusion emerged in four reports published by the Annals of Internal Medicine.

Culling the highest-quality research it could find on preventing Alzheimer’s disease and other dementias, the Minnesota Evidence-based Practice Center concluded that cognitive training has not been shown definitively to work. Neither have prescription medications or over-the-counter dietary supplements. They couldn’t even find a single exercise regimen that fit the bill.

These findings underpinned a recent report by the National Academy of Medicine on preventing dementia. But while the Minnesota group found an absence of decisive effects, it documented some highly suggestive evidence that some things were helpful — in particular, for the effects of exercise, and for strategies, including medications, that manage diabetes and control high blood pressure and worrisome cholesterol at midlife.