Last year, the Alzheimer’s Association predicted that rates of dementia would continue to rise. However, a report recently published in the New England Journal of Medicine found that rates of dementia have actually dropped steadily over the past three decades. Whether the drop in rates applies to everyone, and whether it will continue, remain to be seen. But the evidence also confirms that there’s quite a lot you can do to lower your dementia risk.
A new study published in PLOS One, looked at oxygen related changes and nerve processing in the brain, features that have shown to correlate with better memory and brain function as people age. It found that people with higher fitness levels were the same ones that were more physically active during the week. They were also the same people who showed more positive oxygen related changes and MRI findings consistent with faster nerve processing in the brain. Though there isn’t an exact exercise prescription to guide how long and hard we should exercise, the results of this study and many others, show even low intensity activity for an hour a day is much better for the brain than sitting on the couch.
Of all the health issues that loom large with age, memory loss is among those that provoke the most worry. A big reason is the uncertainty: people often wonder if their occasional memory slips are just a normal part of growing old or a sign of impending Alzheimer’s disease, the most common form of dementia. A new study of older adults, published in today’s issue of the journal Neurology, sheds some light—and perhaps offers a bit of reassurance—about the connection between self-reported memory loss and a diagnosis of dementia. Over a 10-year period as 70-somethings turned into 80-somethings, about 1 in 6 developed dementia. About 80% had reported memory changes. But it took about nine years from the first self-report of a memory change to a diagnosis of mild cognitive impairment, an intermediate stage between normal memory loss and dementia. The transition to dementia usually took about 12 years.
A new report from the Alzheimer’s Association says that as many as 5 million Americans have Alzheimer’s disease or some other form of dementia. Every 67 seconds someone in the United States develops Alzheimer’s disease or dementia. That’s 470,000 Americans this year alone. Given that these thieves of memory and personality are so common and so feared, should all older Americans be tested for them? In proposed guidelines released yesterday, the U.S. Preventive Services Task Force said “no.” Why not? Even after conducting a thorough review of the evidence, the panel said that there isn’t enough solid evidence to recommend screening, especially since not enough is known about the benefits and the harms. In part, the recommendation is based on the sad fact that so far there aren’t any truly effective approaches to stop the forward progress of dementia.
What’s bad for the heart is often bad for the brain. High cholesterol, high blood pressure, diabetes, and unhealthy “hardening” of the arteries increase the risk of mental decline or dementia later in life. A study published online today in Neurology shows that older people with the stiffest arteries are more likely to show the kinds of damage to brain tissue often seen in people with dementia. The study adds support to the “two hit” theory of dementia. It suggests that the accumulation of Alzheimer’s-linked amyloid protein in the brain may not pose problems until damage to small blood vessels that nourish the brain nudges them over into dementia. There may be a silver lining to this line of research: Efforts to improve cardiovascular health can also protect the brain.
There are many reasons to keep your blood sugar under control: protecting your arteries and nerves are two of them. Here’s another biggie: preventing dementia, the loss of memory and thinking skills that afflicts millions of older Americans. A study published today in the New England Journal of Medicine shows that even in people without diabetes, above normal blood sugar is associated with an increased risk of developing dementia. The study does not prove that high blood sugar causes dementia, only that there is an association between the two. For that reason, don’t start trying to lower your blood sugar simply to preserve your thinking skills, cautions Dr. Nathan. There’s no evidence that strategy will work, although he says it should be studied. But it is still worth keeping an eye on your blood sugar. Excess blood sugar can lead to diabetes and a variety of other health problems, including heart, eye, kidney, and nerve disease.