For years we've heard a drumbeat of frightening news about an upcoming epidemic of Alzheimer's disease and dementia poised to rob us of our mental faculties. Now two new studies say the future may not be so bleak. Even better, the new research lends credence to the theory that our behavior can improve our chances of keeping our brains healthy in old age.
One new study finds that dementia rates have fallen by nearly 25 percent in the last 20 years in those 65 and older living in England and Wales. Another recent study finds that the mental performance of Danes in their 90s is improving.
Authors of both of the studies speculate that these results stem from improvements in education levels, nutrition, work environment and fitness - which means we can at least partially control our fate.
An Alzheimer's researcher at Duke University, P. Murali Doraiswamy, M.D., called the British study "terrific news" in the New York Times and said this means we don't have to assume that each generation has the same risk of Alzheimer's disease as the one before it. So it's just possible that the number of people with dementia may not double in the next 30 years as the baby boomer generation ages, as some have predicted.
The British researchers examined a large study that took place between 1989 and 1994 that questioned 7,635 people age 65 and older about lifestyle, income, health, medication and other factors, and then tested around 1,500 of them for dementia. A second part of the study used the same methods to survey 7,796 people age 65 and older between 2008 and 2011.
Using this information, researchers led by Carol Brayne, M.D. at the Cambridge Institute of Public Health, calculated the percentage of the population with dementia two decades ago and in 2011. They found that the percentage of people with dementia dropped by 25 percent from the amount they expected - the more recent generation fared better than the one before it. They published the results Tuesday in the Lancet.
Brayne says that although we shouldn't assume that the study findings in the United Kingdom extend to the United States, some factors - such as heart health - have improved in both countries. Some research in the United States is also finding that the "incidence of dementia has declined, which would suggest that it is not just a U.K. effect," she adds in an e-mail.
In the second study, published last week in the Lancet, Danish researchers also studied two groups of older people - one group born in 1905 and another born in 1915. They tested groups for mental impairment, memory and the ability to carry out daily tasks. The researchers found people born later were a third more likely to reach the age of 95 than those born earlier. They also performed better on the brain and daily living tests. Not only are they living longer, but they are physically fitter and mentally sharper in their old age.
The study challenges stereotypes that people who are living longer are the "very frail and disabled elderly," says lead author Professor Kaare Christensen of the University of Southern Denmark in Odense.
Because older Americans are heavier and have higher rates of diabetes than their British and Danish counterparts - obesity and diabetes are both linked to dementia Alzheimer's disease - researchers say we can't use these studies to adjust estimates about how many people in the United States will get Alzheimer's. And even if dementia rates drop, the number of people with dementia will continue to rise "because the older population is growing at such a fast rate," the Alzheimer's Association said in a statement on the study.
Experts in the United States, however, say dementia rates may fall and cognitive abilities improve as the population's health and education levels improve. In other words, what you do can make a difference in your brain health as you age.
Stay tuned in this new AARP healthy brain blog for more information on the latest research that can help guide you to understanding how to do just that.
Photo credit: floridahomesmag
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