Summary: The prevalence of dementia in older Americans seems to be decreasing. Whether or not researchers find new medicines to prevent dementia, higher levels of education and late-life activity might reduce dementia rates.
Ken Langa, MD, Ph.D.
Much has been written about the coming “silver tsunami” and the expected “epidemic” of Alzheimer’s and other dementias. My conversations with eldercare professionals here on the west coast of Florida seem to confirm these predictions. But in the U.S. overall, the numbers suggest the situation might not be so dire.
Researchers at the University of Michigan recently analyzed data on cognitive impairment from the Health and Retirement Study, a large survey of older Americans. Along with his colleagues, Ken Langa, an Internist and Professor at the university, surveyed more than 7000 people over the age of 70 in 1993. They found 12.2 percent had cognitive impairment “consistent with dementia.” In their similar 2002 survey, that percentage decreased to 8.7, a relative decrease of almost 30 percent.
Dr. Langa, whose work focuses on the epidemiology and costs of Alzheimer’s and other dementias, is the lead author on another recent study suggesting the use of Medicare claims to calculate dementia prevalence and costs of related care results in overstatement of both.
The University of Michigan studies are not the first to highlight this trend. A Duke University analysis published in 2005 showed the percentage of Americans over 65 with severe cognitive impairment declined from 5.7 to 2.9 from 1982 to 1999.
These numbers are not much comfort to people already affected by dementia, but from a public health point of view, this is really good news.
Why the decline in dementia rates?
In the 2002 University of Michigan survey, people 70 and older were more highly educated and wealthier than those in the 1993 survey. Analysis showed that the combination of these trends contributed to the decline in dementia rates, the researchers say. It’s also possible that better treatment of stroke and heart disease risks (high blood pressure, for example) were helpful, they write.
The idea that education could contribute to a decrease in dementia may be related to the concept of cognitive reserve, or an ability to compensate for problems in the brain. In theory, education can increase cognitive reserve, which can delay the onset of dementia symptoms. Delaying the onset of dementia until closer to the end of life reduces the burden of care, of course.
The results of this study seem to support the cognitive reserve theory. Compared with the 1993 survey, people in the 2002 survey who did have cognitive impairment had a higher risk of death. This might mean they had delayed symptoms until close to the end of life.
A general increase in intelligence and longer work lives – two trends that may be related to education and wealth -- may also contribute to lower dementia rates.
Maybe we’re just getting smarter
As documented by a researcher named James Flynn, intelligence quotients (IQs) seem to be rising in many countries. Could higher intelligence in the overall population (which may increase “cognitive reserve”) contribute to lower rates of dementia? “Yes,” says Dr. Langa. “These two trends may both be related to increasing levels of education. The so-called ‘Flynn Effect,’ which describes the general increase in average IQ in the population over the last decades, may be related to increasing levels of education in later cohorts of adults in a similar way to what we hypothesized in our study for the decreasing risk of dementia over time due to increasing levels of education in later cohorts.”
Does putting off retirement help?
Other researchers at the University of Michigan have published data showing a link between early retirement and problems with memory and thinking. The percentage of older Americans still working has increased since 1990, even in those 70 and older. Could this trend also be contributing to the decreasing prevalence of dementia?
“That is definitely a possibility, but we did not test that specifically in our study,” says Dr. Langa. “This is still quite a complex relationship, so more research needs to be done to sort out the relationships among education, wealth, occupation, retirement age, and the risk of dementia.”
Will dementia rates continue to decline?
The apparent trend towards lower rates of dementia is encouraging, but it’s hard to say if it will continue. One reason is we don’t have a full understanding of how various social, economic and medical factors affect those rates.
For example, the net worth of many older Americans has decreased sharply in the last couple of years. Will this affect the prevalence of dementia?
“That's an interesting question,” says Dr. Langa. “I just don't think we know how the financial crisis will affect middle-age and older adults in the long-term. If the decrease in wealth causes some to have much higher levels of stress and manage their health problems worse (for instance, not taking their blood pressure medications), this might lead to a higher dementia risk over time. But if the financial crisis ends up causing some adults to stay in the work force longer, that might actually end up decreasing dementia risk through the pathways we discussed above. So I think it's plausible that the financial crisis might have an impact in different directions, or perhaps none at all.”
Education and engagement: better than drugs?
Advocacy organizations are calling for increased funding for biomedical research on Alzheimer’s. But should we also be asking for government policies to increase funding for education and for programs that encourage older Americans to work or otherwise stay active? Could these policies have the potential to reduce the burden of caring for people with dementia as much as future pharmaceutical treatments?
“It is hard to make sure-fire recommendations or predictions,” Dr. Langa says, “but I do believe that policies that encourage the widest possible access to education for children from all socioeconomic levels might be significantly more beneficial for population "brain health" (and health, in general) than future pharmaceutical treatments for dementia. Government policies that allow older adults to keep working at jobs they enjoy, or engaging in cognitively stimulating activities when they retire, would also be beneficial for the brain health of our population. Of course, the science and politics required to successfully expand childhood and adult education opportunities for all are not straightforward, but I do think that keeping these goals high on our political agenda could have wide-ranging benefits for the health of future generations.”
These numbers are not much comfort to people already affected by dementia, but from a public health point of view, this is really good news.
Why the decline in dementia rates?
In the 2002 University of Michigan survey, people 70 and older were more highly educated and wealthier than those in the 1993 survey. Analysis showed that the combination of these trends contributed to the decline in dementia rates, the researchers say. It’s also possible that better treatment of stroke and heart disease risks (high blood pressure, for example) were helpful, they write.
The idea that education could contribute to a decrease in dementia may be related to the concept of cognitive reserve, or an ability to compensate for problems in the brain. In theory, education can increase cognitive reserve, which can delay the onset of dementia symptoms. Delaying the onset of dementia until closer to the end of life reduces the burden of care, of course.
The results of this study seem to support the cognitive reserve theory. Compared with the 1993 survey, people in the 2002 survey who did have cognitive impairment had a higher risk of death. This might mean they had delayed symptoms until close to the end of life.
A general increase in intelligence and longer work lives – two trends that may be related to education and wealth -- may also contribute to lower dementia rates.
Maybe we’re just getting smarter
As documented by a researcher named James Flynn, intelligence quotients (IQs) seem to be rising in many countries. Could higher intelligence in the overall population (which may increase “cognitive reserve”) contribute to lower rates of dementia? “Yes,” says Dr. Langa. “These two trends may both be related to increasing levels of education. The so-called ‘Flynn Effect,’ which describes the general increase in average IQ in the population over the last decades, may be related to increasing levels of education in later cohorts of adults in a similar way to what we hypothesized in our study for the decreasing risk of dementia over time due to increasing levels of education in later cohorts.”
Does putting off retirement help?
Other researchers at the University of Michigan have published data showing a link between early retirement and problems with memory and thinking. The percentage of older Americans still working has increased since 1990, even in those 70 and older. Could this trend also be contributing to the decreasing prevalence of dementia?
“That is definitely a possibility, but we did not test that specifically in our study,” says Dr. Langa. “This is still quite a complex relationship, so more research needs to be done to sort out the relationships among education, wealth, occupation, retirement age, and the risk of dementia.”
Will dementia rates continue to decline?
The apparent trend towards lower rates of dementia is encouraging, but it’s hard to say if it will continue. One reason is we don’t have a full understanding of how various social, economic and medical factors affect those rates.
For example, the net worth of many older Americans has decreased sharply in the last couple of years. Will this affect the prevalence of dementia?
“That's an interesting question,” says Dr. Langa. “I just don't think we know how the financial crisis will affect middle-age and older adults in the long-term. If the decrease in wealth causes some to have much higher levels of stress and manage their health problems worse (for instance, not taking their blood pressure medications), this might lead to a higher dementia risk over time. But if the financial crisis ends up causing some adults to stay in the work force longer, that might actually end up decreasing dementia risk through the pathways we discussed above. So I think it's plausible that the financial crisis might have an impact in different directions, or perhaps none at all.”
Education and engagement: better than drugs?
Advocacy organizations are calling for increased funding for biomedical research on Alzheimer’s. But should we also be asking for government policies to increase funding for education and for programs that encourage older Americans to work or otherwise stay active? Could these policies have the potential to reduce the burden of caring for people with dementia as much as future pharmaceutical treatments?
“It is hard to make sure-fire recommendations or predictions,” Dr. Langa says, “but I do believe that policies that encourage the widest possible access to education for children from all socioeconomic levels might be significantly more beneficial for population "brain health" (and health, in general) than future pharmaceutical treatments for dementia. Government policies that allow older adults to keep working at jobs they enjoy, or engaging in cognitively stimulating activities when they retire, would also be beneficial for the brain health of our population. Of course, the science and politics required to successfully expand childhood and adult education opportunities for all are not straightforward, but I do think that keeping these goals high on our political agenda could have wide-ranging benefits for the health of future generations.”
Couldn't the percentage of persons with full-fledged dementia be reducing because people with the earlier signs of mild cognitive impairment are getting medical help AND are developing their own strategies of nutraceuticals, physical activity, creative arts, good sleep, better nutrition, stress reduction, reduced exposure to toxins, meaningful work, and enjoyable life, and that this is slowing or reducing their move toward dementia? That is certainly the case for me and many others that I know with early MCI. Mary Kay Baum of forMemory, Inc.
Posted by: Mary Kay Baum | December 08, 2010 at 08:33 AM
Hello, an interesting observation. Sure knocks some of the wind out of the hurricane of hot air blowing for doubling the funding for research in one specific type of dementia. It's a very complicated subject to come up with an a simple and sweeping conclusion.
But it sure is worth deeper investigation. The disability may not be revealing itself, but the underlieing process may still be going on, we are just getting better at covering it up for longer periods of time. Brains are aging at the same rate, and there are more and more older brains in the population. Seems counter intuitive that the conditions associated with aging brains should be decreasing at the same time the number of brains at risk is increasing.
Stay tuned, I will
Richard Taylor
Person living with the symptoms of dementia
richardtaylorphd.com
Posted by: richard taylor | December 08, 2010 at 03:20 PM
OMG! Maybe its not a tsunami, its just a large tidal wave
And so now some are suggesting the let's find a cure for Alzheimer's, or at least keep people with dementia out of nursing homes for an additional year through the miracles of drugs movement and thus save lots and lots of tax payers' dollars and Medicare and Medicaid claims may not be as compelling as advertised.
Ignore the psychosocial human side of this public health crisis and focus on economics, that is what we are told in many, many pleadings for more money to spend on research.
Epidemiologists are beginning to suggest there is a decline in the numbers of folks living with cognitive disabilities. No one goes around door to door asking everyone (even those standing in a closet) who is exhibiting the symptoms of dementia to stand up and be counted, but through various surveys there is the smell of a trend that at least the symptoms of dementia may be observable in fewer people than we have been led to believe.
I know for sure that all brains age. And I know for sure we now live in a time where there are lots of old brains walking around in every country in the world. What happened seventy years ago (WW II), and the tsunami of sexual contacts just after the war has now produced a world with lots and lots of living 50-60-70 year old human brains. If dementia is a natural consequence of an aging brain then shouldn't there be more and more brains walking around the world (actually they don't walk, they are carried around by the body at the top of which the live) exhibiting the symptoms of dementia?
It's possible many of us are better prepared to cover up the symptoms. More formal education, social and mental stimulation, better diets, lower blood pressure and cholesterol all seem to reduce the probability of someone acting like they have dementia. Since only our brains know for sure, and they are not confiding in anyone, we can only guess by our behaviors - what we say and do, if we know who the president of the united state is and how quickly we can tell someone his/her name, and other probing and revealing questions that must be answered on a computer and/or with a paper and pencil (or pen if it is black ink).
Some folks have a vested interest in counting as many folks as possible and some have a vested interest in counting as few folks as possible - both groups are counting the number of people who appear through whatever test is being used to be exhibiting the symptoms of dementia. There are even a group of folks who now claim to be able to count you in or out before you show any symptoms - they look at images of your brain, the color of the images, if the computer is making parts of the image flash, and other technological tricks. Another group is basing their count on your genes. If you have this or that, or this or that combination you, may/might/will have this or that form of dementia - provided of course you do not die before you show the symptoms.
This is a messy process, this counting stuff. It means a lot to politicians, researchers, and Alzheimer's Associations - just how big the estimates are or are not. To someone living with the symptoms it means little to nothing, other than to confirm that all of us should not be really really sure about anyone who claims to be an expert about the number of people living with the symptoms of dementia. We should all also question for ourselves if what they are shouting at us is indeed a fact - a truth for all of us - or their opinion/hopes/wishes/guesses as to what is and is or is not a truth for all of us.
Personally, I didn't need this latest bit of information to be suspicious of dementia experts, but perhaps you do/did. It would be great news of more and more of us were more and more able to disguise/cover up/repress and otherwise keep hidden our symptoms of dementia. It would be great news if less and less of us had the need to cover up the symptoms because there is no need to cover up something that isn't there in the first place. In either of these cases the stigmas, myths, and fears residing in the brains of most all folks over the age of about three years old are just as strong, just as prevalent.
Maybe we shouldn't be scared into doing something about dementia based on economic arguments (the costs may be inflated). Maybe we should just do something(s) about dementia and the people living with its symptoms because it's the right thing(s) to do. And maybe the emphasis on the some things we do should first be on discovering cures for the day-to-day problems of living with the symptoms of dementia. From my heart and mind, there is no maybe about this.
Richard
Posted by: richard taylor | December 08, 2010 at 04:57 PM
Mary Kay, thanks so much for your comment. The researchers addressed part of your question in their article. They wrote this about the increasing use of cholinesterase inhibitors to treat Alzheimer's:
Because these medications are used mainly only after diagnosis of dementia, and because their impact on cognitive function is modest, it is highly unlikely that they are an important explanation for the decreased prevalence of CI between 1993 and 2002 that we found in our study.
I don't think they addressed other types of medicines, or your comments about lifestyle changes.
Posted by: Mona Johnson | December 10, 2010 at 02:59 PM
Richard, thanks so much for your comments. You're right, of course, people with cognitive problems and their families don't really care how prevalence numbers and costs are calculated - they know their personal costs are high.
From a public policy point of view, I do think it's important for us to understand how various prevalence numbers and cost figures are developed. I would guess it's also important for pharmaceutical company planning.
Posted by: Mona Johnson | December 10, 2010 at 03:07 PM
Interesting, Richard, that you point out how some groups have a "vested interest" in either a growing or a decreasing rate of dementia. Can't blame those fighting for a cure for being alarmists, and can't blame those fighting for human dignity for minimizing the scope of the problem. So how are we to arrive at "truth"? I would like to know, for example, how the number 5.3 million is arrived at in the U.S.--for comparative purposes with other countries SO THAT we can get more of a feel for the underlying causes. If we overestimate our numbers and other countries underestimate their numbers, it may make us overlook some very important factors that we could use to get a handle on this disease. (On underestimates, I'm thinking specifically of East Asian countries given that it is anathema to say you have dementia in Asian Pacific cultures).
Posted by: Marty | December 11, 2010 at 12:21 PM
A healthy lifestyle is crucial to a sharp memory. In particular, stress management is often under-estimated in a brain fitness program. The Alzheimer's Research and Prevention Foundation sponsored several research studies on the 12-minute Kirtan Kriya singing meditation, and the results were improved attention, focus, concentration, and memory. More information is available online at www.alzheimersprevention.org/research
Posted by: Alzhimer's Research and Prevention foundation | February 08, 2011 at 01:19 PM