New study gives insight into resistance to Alzheimer's

Low rates of the disease and dementia may run in families

By Bonnie Miller Rubin, Chicago Tribune reporter

August 22, 2012


Everyone will exhibit some kind of cognitive decline with advancing years. But the idea that we can shield ourselves from the most devastating brain diseases,Alzheimer's disease and dementia, is an intriguing prospect and an area of great interest to scientists and an aging population.

In a new study published last week in the journal Neurology, researchers identified a group of elderly men with no mental impairments to find out about their relatives' brains. We turned to the study's lead author, Jeremy Silverman, a clinical psychologist and professor of psychiatry at Mount Sinai School of Medicine in New York City, to tell us more.

Q: How did you conduct the study?

A: Our sample consisted of almost 300 men age 75 and older with no symptoms of dementia. The men were tested to measure their level of C-reactive proteins and asked questions about their parents and siblings — more than 1,300 — to determine how many had dementia. The results were 40 relatives from 37 families. This is lower than the usual rate of dementia of people that age but is consistent with other studies that relatives of elderly people without dementia have low rates of dementia. There was even a smaller percentage of dementia in a second sample of relatives of cognitively healthy subjects 85 and older.

Q: What's the key finding of the study?

A: That in very old cognitively intact males, those who have high levels of C-reactive protein (CRP) have relatives who may be at lower risk for dementia.

Q. What is C-reactive protein?

A. It's a protein that is synthesized in the liver and is related to inflammation. In an earlier study of cognitive healthy, very elderly people, the higher the level of this protein, the better their memory function. This is not what you'd expect to find, since inflammation is often associated with cognitive impairment.

Q: Inflammation sounds like something bad.

A: Inflammation is not usually a good thing, but if a very elderly person has good cognition despite inflammation, this may demonstrate resistance to damaging effects, rather than having inflammation harm them.

Q: So what do we know that we didn't know before?

A: In very elderly people with good cognition despite high CRP, their relatives may have lower risk for dementia. This suggests that this characteristic may run in families, which reflect genetic inheritance, or perhaps a common environment.

Q: Since we can't just go out and buy CRP pills, I'm not clear on how the study helps us.

A: This study doesn't suggest that high CRP is good for anyone, only that it may not be bad for some exceptional people. The area of successful cognitive aging is relatively new and hasn't gotten a great deal of attention. ... Studying people who are doing really, really well may be a window into healthy brain function and perhaps lead us to identify genes or other protective factors. If we can do that, we might be able to better understand the mechanism involved in dementia and come up with preventive strategies.

Q: Are there some other lifestyle components that can stave off Alzheimer's disease and other brain impairments?

A: Physical activity seems to be an important factor that carries protection. The same is true of a healthy diet, not smoking, controlling cholesterol. Cardiovascular disease is not only bad for your heart but also your cognitive abilities.

Q: What about stress? Does that play a part in Alzheimer's?

A: Well, this is a question being studied now, but the answer is still out.

Q: So, it's not enough to do Sudoku or play Scrabble?

A: It's great to keep your mind alive and alert. But there's some evidence that physical activity seems to play a stronger role.

Q: Honestly, I'd rather pick up the crossword puzzle. You mean I have to put down the corned beef sandwich too?

A: I've been a vegetarian since age 14, so I'm probably not the best one to ask … but the same diet that is good for your heart seems to be better for your brain too.