Almost one in four deaths in America are caused by heart disease and one in six are caused by Alzheimer’s disease, which is a dementia related disorder characterized by memory loss, forgetfulness and behavioral changes. There are many causes of these two major killers, and scientists have long assumed that what is bad for your heart is also bad for your brain. This assumption was made because previous studies had found a link between high cholesterol levels and/or high levels of the inflammatory marker ‘C-reactive protein’ (CRP) and an increased risk for both heart disease and dementia. Recent studies however, have yielded some contradicting results — results which suggest that what’s bad for the heart may actually be beneficial to the brain, at least in the elderly.
The most recent study was conducted on 277 male veterans, all of whom were free of common dementia symptoms such as forgetfulness and memory loss. The study participants had their levels of CRP tested and then they were questioned about whether or not their parents or siblings had dementia. A second group of 51 men who were free of dementia symptoms were also interviewed about their relatives and whether or not they showed signs of dementia. The researchers controlled for education, occupation, physical activity and marital status, in order to assure these factors did not skew the results.
The study which was published on the August 15th found that the participants who had higher levels of CRP were 30 percent less likely to have relatives with dementia and the men with the highest levels of CRP were a whopping 50 percent less likely to have parents or siblings with dementia. The study author concluded that “Relatives of successful cognitive aging individuals with high levels of CRP are relatively likely to remain free of dementia.”
The findings of this study were in direct contrast with previous studies such as the “Honolulu-Asia Aging Study” which found that individuals in midlife with high CRP levels had a three-fold increased risk for developing dementia. “This protein (CRP) is related to worse cognition in younger elderly people. Thus, for very old people who remain cognitively healthy, those with a high protein level may be more resistant to dementia,” said study author Jeremy M. Silverman, PhD, with Mount Sinai School of Medicine in New York.
Another study also yielded results which conflict with the assumption that markers which increase heart disease risk also increase dementia risk. The researchers of this study measured the cholesterol blood levels of 185 individuals who were dementia free and 85 or older. In contrast to previous findings, this study found that high total cholesterol and high low-density (LDL) cholesterol levels, both of which increase an individual’s heart disease risk, were associated with higher memory scores, better memory function and increased overall cognitive performance.
“It’s not that these things (high CRP and high cholesterol) suddenly become good for your brain later in life. Instead, these older individuals and their families probably have genes protecting them against these risk factors, allowing them to stay healthy in spite of high cholesterol and CRP,” states Christopher Intagliata in Scientific American Magazine. Researchers are now trying to zero in on the purported ‘dementia-proof genes’ in order to create a mechanism that mimics the protective system that they create and thereby protect the greater population from developing dementia.