THE number of people affected by dementia may be rising, but most specialists say that鈥檚 largely because more of us are living longer. Between the late 1980s and 2011, the proportion of people over 65 with dementia in England and Wales. Between 2000 and 2012, dementia rates . have been reported in other developed countries.
There are two driving factors, says Kenneth Langa at the Michigan Center on the Demography of Aging, who tracked the US trend: a rise in educational attainment and better control of cardiovascular issues.
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Read more: Defying dementia
As we hunt down cures for dementia, one of today鈥檚 most feared illnesses, there are ways to fend off symptoms for longer
After the second world war, there was an increase in schooling that averaged out to about an extra year of education across the US population. Research suggests that people with more education, or those who have done things like learn a new language or learn to play a musical instrument, may be resilient to symptoms of dementia.
That doesn鈥檛 mean they escape the ravages of vascular dementia or plaques of Alzheimer鈥檚, but they may cope better with the damage. 鈥淏y challenging your brain during education, you create a more fit brain that can compensate for problems that you have as you age,鈥� Langa says.
Increased cognitive reserve is thought to help in two ways: boosting the brain鈥檚 ability to work around damaged areas, and promoting more efficient processing. That might also explain why people with more education seem to decline so rapidly: it鈥檚 not that Alzheimer鈥檚 comes on suddenly, it鈥檚 that by the time symptoms manifest the disease may already be quite advanced.
As for cardiovascular risk factors, while the prevalence of conditions such as high blood pressure and diabetes has risen over the years, there has also been an increase in treatments that can limit their damage.
But poorer countries haven鈥檛 seen such advances. And despite improvements in wealthier nations, the absolute number of dementia cases will probably continue to climb 鈥� the decline in prevalence isn鈥檛 steep enough to make up for the rising tide of ageing baby boomers, says John Haaga at the US National Institute on Aging. 鈥淧eople are living longer 鈥� and that鈥檚 great. We鈥檙e also living with our wits intact for much longer,鈥� Haaga says. 鈥淏ut we can鈥檛 deny that we have a much larger population of ageing persons to contend with in the future.鈥� What鈥檚 more, there is not a significant educational attainment difference between 65-year-olds and 25-year-olds today, and metabolic diseases like diabetes are on the rise. That means gains we鈥檝e made may not continue apace.
It is also important to acknowledge that much of dementia risk is down to genetics, about 70 per cent in the case of Alzheimer鈥檚 disease, says at University College London. Too often he sees patients lamenting that they didn鈥檛 do enough, but sometimes there is only so much you can do. 鈥淲e know that some people have strong genetic risk factors that can predispose them to some forms of dementia whether they live a healthy lifestyle or not,鈥� he says.
20 per cent of dementia cases around the world could be avoided with improvements in public health
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Still, if 30 per cent or more of dementia risk is down to lifestyle and environmental factors, there is an opportunity to make a difference. Maintaining social connections, keeping a healthy diet, exercising regularly, practising good sleep habits and pursuing intellectual challenges may all delay or lessen symptoms of dementia later in life. 鈥淲alk, talk and read,鈥� says Langa. And do it now. 鈥淭hese changes have the most effect when they are started earlier in life.鈥�
Physical activity may be most critical. Regular exercise not only addresses risk factors such as weight and cardiovascular health, but it increases the creation of brain cells, connections between neurons, and production of nerve growth factors and neurotransmitters, says at University of Illinois at Urbana-Champaign.
You don鈥檛 have to run ultra-marathons to reap the benefits. Just an hour-long walk a few times a week can make a difference.
Should you test your genes?
WITH about two dozen genes accounting for 70 per cent of your Alzheimer鈥檚 risk 鈥� the only kind of dementia we can do genetic tests for 鈥� taking a test may seem like a simple choice. But with no cure in sight, what can you do with the results?
Having the APOE4 gene variant, for instance, only means you have a higher risk of Alzheimer鈥檚, not that you will get it. Genes associated with early-onset Alzheimer鈥檚, such as certain mutations of APP, PSEN1 and PSEN2, are more definitive. But even those with a family history of the disease struggle with whether to get tested. Carol Jennings (see 鈥�What is dementia like?鈥�) knew she had a 50 per cent chance of having the faulty APP gene, but didn鈥檛 want the test. With no cure, what was the point?
Only when symptoms began did she finally get tested. Now Jennings鈥檚 two adult children, who may have the same mutation, face that difficult decision. One doesn鈥檛 want the test; the other hopes the results can guide future plans.
It鈥檚 understandable that genetic testing prompts mixed feelings. Today it is mostly useful for identifying candidates for clinical trials, and to help researchers understand the disease and potential treatments, says Laurie Ryan at the US National Institute on Aging. 鈥淚t can鈥檛 tell us anything like, 鈥業f you have this variant, we need to do this to help you鈥�.鈥�
What are the warning signs?
WHEN it comes to memory, all of us get a bit creakier as we age. It鈥檚 common to forget the specific word you were searching for, miss the occasional appointment or misplace your car keys. 鈥淚t happens to all of us,鈥� says at the University of Brighton, UK.
So when might a memory issue be more than just a little extra creakiness? Because so many things can cause dementia, symptoms and severity can vary greatly, making it difficult to catch the earliest warnings. But common signs include problems with short-term memory, abstract thinking, the ability to focus, visual perception and communication.
There鈥檚 no reason to be alarmed if you do have the odd 鈥渟enior鈥� moment. For one thing, people of all ages have differences in memory, says , director of the Nantz National Alzheimer Center at Houston Methodist Hospital in Texas. And as well as slowing down, certain skills shift as we get older. 鈥淢ultitasking, the ability to deploy attention to multiple things at the same time, becomes more difficult,鈥� says , director of medical psychology at Johns Hopkins University in Baltimore, Maryland.
One warning sign might be the inability to summon a memory even when prompted. With normal ageing, it might take you longer to remember, says Brandt, but at early stages of Alzheimer鈥檚, having more time won鈥檛 help because 鈥渢he information has degraded鈥�. When these types of shifts happen, or memory or cognitive problems begin to interfere with daily life, it鈥檚 time to consult a doctor.
午夜福利1000集合care professionals have tools to help catch problems early. To assess patients over 60, most use some version of the , which asks simple questions about time and place and is designed to measure cognitive impairment. Doctors may also test working memory by asking people to count backwards from 100 in 7s or remember three unrelated items after a period of time. If you score poorly on these kinds of tests, you should expect to be referred for further testing.
For people who want personalised feedback from home, Brandt and his team developed an online tool. It includes a series of memory tests, as well as a questionnaire about different risk factors for dementia. 鈥淭his enables people to do something in the privacy of their home,鈥� he says. If there is something worrying, it directs you to follow it up with your doctor. The test can be found at .
Will we find a cure?
NEWS headlines seem to announce promising new treatments for dementia each month. But while many drugs have helped prevent or reverse dementia-like pathology in animal models, they have so far failed to do so in human clinical trials.
With Alzheimer鈥檚, many drugs have focused on clearing excess beta-amyloid from the brain. But several clinical trials have been cancelled because of lacklustre performance.
In fact, the medications barely stood a chance of helping the people they were tested on, says Joseph Masdeu at Houston Methodist Hospital in Texas. 鈥淭he drugs were not given until the participants already had cognitive problems. The damage was already done.鈥� But if given to people when they are unimpaired, many researchers are confident drugs could make a difference.
Both beta-amyloid and tau proteins can be seen in brain scans decades before there are cognitive issues (see 鈥�Defying dementia: It is not inevitable鈥�). That offers a window for intervention.
But which individuals should be targeted for these kinds of measures? An area of intense research is to identify definitive signs of dementia in the body. Finding an equivalent of cholesterol, a biomarker that, although imperfect, helps doctors understand who is at risk of heart disease, would be a game-changer. It would allow doctors to screen patients early for potential disease 鈥� and decide who would benefit from different preventive approaches, says Kenneth Langa at the Michigan Center on the Demography of Aging.
The lack of progress isn鈥檛 for lack of trying. There are studies of families and groups with early-onset Alzheimer鈥檚, the largest of which is known as the Colombia cohort. Teams are feverishly hunting for genetic and environmental factors that affect dementia risk. There are analyses of long-term studies like that tracking a group born in the UK in 1946. There are trials involving people with the APOE4 gene variant, known to increase risk of late-onset Alzheimer鈥檚 鈥� particularly in women. And there are efforts to use neuroimaging to identify amyloid build-up ever earlier.
Teams are investigating ways to treat inflammation that may cause dementia鈥檚 cognitive symptoms after amyloid build-up as well, and focusing on agents that may offer neuroprotection or neuroregeneration.
鈥淭here are a lot of pieces to this puzzle,鈥� says Laurie Ryan at the National Institute on Aging. 鈥淚t鈥檚 likely there will be different treatments and interventions for different patients if we really want to affect change in the long term.鈥� Langa agrees. 鈥淭he next 10 to 20 years will be very interesting,鈥� he says. 鈥淲e can do more to get in there and intervene to decrease the risk and prevalence of dementia. We鈥檙e doing the work.鈥�
This article appeared in print under the headline 鈥淲hat can you do to avoid dementia?鈥�
