Eyes provide peek at Alzheimer’s disease risk

August 23, 2021

Science Daily/University of California - San Diego

Amyloid plaques are protein deposits that collect between brain cells, hindering function and eventually leading to neuronal death. They are considered a hallmark of Alzheimer's disease (AD), and the focus of multiple investigations designed to reduce or prevent their formation, including the nationwide A4 study.

But amyloid deposits may also occur in the retina of the eye, often in patients clinically diagnosed with AD, suggesting similar pathologies in both organs. In a small, cross-sectional study, a team of researchers, led by scientists at University of California San Diego School of Medicine, compared tests of retinal and brain amyloids in patients from the A4 study and another study (Longitudinal Evaluation of Amyloid Risk and Neurodegeneration) assessing neurodegeneration risk in persons with low levels of amyloid.

Like the proverbial "windows to the soul," the researchers observed that the presence of retinal spots in the eyes correlated with brain scans showing higher levels of cerebral amyloid. The finding suggests that non-invasive retinal imaging may be useful as a biomarker for detecting early-stage AD risk.

The findings published in the August 17, 2021 issue of Alzheimer's & Dementia.

"This was a small initial dataset from the screening visit. It involved eight patients," said senior author Robert Rissman, PhD, professor of neurosciences at UC San Diego School of Medicine and director of the Biomarker Core for the Alzheimer's Disease Cooperative Study and Alzheimer's Disease Research Center at UC San Diego. "But these findings are encouraging because they suggest it may be possible to determine the onset, spread and morphology of AD -- a preclinical diagnosis -- using retinal imaging, rather than more difficult and costly brain scans. We look forward to seeing the results of additional timepoint retinal scans and the impact of solanezumab (a monoclonal antibody) on retinal imaging. Unfortunately we will need to wait to see and analyze these data when the A4 trial is completed."

The next step, said Rissman, will be to conduct a larger study to more fully document and ascertain the relationship between retinal amyloid and cerebral amyloid, both cross-sectionally and over time.

https://www.sciencedaily.com/releases/2021/08/210823125758.htm

Having a good listener improves your brain health

August 16, 2021

Science Daily/NYU Langone Health / NYU Grossman School of Medicine

Researchers find having someone to listen to you when you need to talk is associated with greater cognitive resilience. New study shows social interaction in adulthood can stave off cognitive decline despite brain aging.

Supportive social interactions in adulthood are important for your ability to stave off cognitive decline despite brain aging or neuropathological changes such as those present in Alzheimer's disease, a new study finds.

In the study publishing August 16 in JAMA Network Open, researchers observed that simply having someone available most or all of the time whom you can count on to listen to you when you need to talk is associated with greater cognitive resilience -- a measure of your brain's ability to function better than would be expected for the amount of physical aging- or disease-related changes in the brain, which many neurologists believe can be boosted by engaging in mentally stimulating activities, physical exercise, and positive social interactions.

"We think of cognitive resilience as a buffer to the effects of brain aging and disease," says lead researcher Joel Salinas, MD, the Lulu P. and David J. Levidow Assistant Professor of Neurology at NYU Grossman School of Medicine and member of the Department of Neurology's Center for Cognitive Neurology. "This study adds to growing evidence that people can take steps, either for themselves or the people they care about most, to increase the odds they'll slow down cognitive aging or prevent the development of symptoms of Alzheimer's disease -- something that is all the more important given that we still don't have a cure for the disease."

An estimated 5 million Americans are living with Alzheimer's disease, a progressive condition that affects mostly those over 65 and interferes with memory, language, decision-making, and the ability to live independently. Salinas says that while the disease usually affects an older population, the results of this study indicate that people younger than 65 would benefit from taking stock of their social support. For every unit of decline in brain volume, individuals in their 40s and 50s with low listener availability had a cognitive age that was four years older than those with high listener availability.

"These four years can be incredibly precious. Too often we think about how to protect our brain health when we're much older, after we've already lost a lot of time decades before to build and sustain brain-healthy habits," says Salinas. "But today, right now, you can ask yourself if you truly have someone available to listen to you in a supportive way, and ask your loved ones the same. Taking that simple action sets the process in motion for you to ultimately have better odds of long-term brain health and the best quality of life you can have."

Salinas also recommends that physicians consider adding this question to the standard social history portion of a patient interview: asking patients whether they have access to someone they can count on to listen to them when they need to talk. "Loneliness is one of the many symptoms of depression, and has other health implications for patients," says Salinas. "These kinds of questions about a person's social relationships and feelings of loneliness can tell you a lot about a patient's broader social circumstances, their future health, and how they're really doing outside of the clinic."

How the Study Was Conducted

Researchers used one of the longest running and most closely monitored community-based cohorts in the U.S., the Framingham Heart Study (FHS), as the source of their study's 2,171 participants, with an average age of 63. FHS participants self-reported information on the availability of supportive social interactions including listening, good advice, love and affection, sufficient contact with people they're close with, and emotional support.

Study participants' cognitive resilience was measured as the relative effect of total cerebral brain volume on global cognition, using MRI scans and neuropsychological assessments taken as part of the FHS. Lower brain volumes tend to associate with lower cognitive function, and in this study, researchers examined the modifying effect of individual forms of social support on the relationship between cerebral volume and cognitive performance.

The cognitive function of individuals with greater availability of one specific form of social support was higher relative to their total cerebral volume. This key form of social support was listener availability and it was highly associated with greater cognitive resilience.

Researchers note that further study of individual social interactions may improve understanding of the biological mechanisms that link psychosocial factors to brain health. "While there is still a lot that we don't understand about the specific biological pathways between psychosocial factors like listener availability and brain health, this study gives clues about concrete, biological reasons why we should all seek good listeners and become better listeners ourselves," says Salinas.

https://www.sciencedaily.com/releases/2021/08/210816112101.htm

Microbes turn back the clock as research discovers their potential to reverse aging in the brain

August 9, 2021

Science Daily/University College Cork

Research from APC Microbiome Ireland (APC) at University College Cork (UCC) published today in the leading international scientific journal Nature Agingintroduces a novel approach to reverse aspects of aging-related deterioration in the brain and cognitive function via the microbes in the gut.

As our population ages one of the key global challenges is to develop strategies to maintain healthy brain function. This ground-breaking research opens up a potentially new therapeutic avenues in the form of microbial-based interventions to slow down brain aging and associated cognitive problems.

The work was carried out by researchers in the Brain-Gut-Microbiota lab in APC led by Prof John F. Cryan, Vice President for Research & Innovation, University College Cork as well as a Principal Investigator at APC Microbiome Ireland an SFI Research Centre, based in in University College Cork and Teagasc Moorepark.

There is a growing appreciation of the importance of the microbes in the gut on all aspects of physiology and medicine. In this latest mouse study the authors show that by transplanting microbes from young into old animals they could rejuvenate aspects of brain and immune function. Prof John F. Cryan, says "Previous research published by the APC and other groups internationally has shown that the gut microbiome plays a key role in aging and the aging process. This new research is a potential game changer , as we have established that the microbiome can be harnessed to reverse age-related brain deterioration. We also see evidence of improved learning ability and cognitive function." Although very exciting Cryan cautions that "it is still early days and much more work is needed to see how these findings could be translated in humans."

https://www.sciencedaily.com/releases/2021/08/210809122202.htm

Fine particulate air pollution associated with higher risk of dementia

August 4, 2021

Science Daily/University of Washington

Using data from two large, long-running study projects in the Puget Sound region -- one that began in the late 1970s measuring air pollution and another on risk factors for dementia that began in 1994 -- University of Washington researchers identified a link between air pollution and dementia.

In the UW-led study, a small increase in the levels of fine particle pollution (PM2.5 or particulate matter 2.5 micrometers or smaller) averaged over a decade at specific addresses in the Seattle area was associated with a greater risk of dementia for people living at those addresses.

"We found that an increase of 1 microgram per cubic meter of exposure corresponded to a 16% greater hazard of all-cause dementia. There was a similar association for Alzheimer's-type dementia," said lead author Rachel Shaffer, who conducted the research as a doctoral student in the UW Department of Environmental & Occupational Health Sciences.

"The ACT Study is committed to advancing dementia research by sharing its data and resources, and we're grateful to the ACT volunteers who have devoted years of their lives to supporting our efforts, including their enthusiastic participation in this important research on air pollution," said Dr. Eric Larson, ACT's founding principal investigator and a senior investigator at KPWHRI.

The study, published Aug. 4 in the journal Environmental Health Perspectives, looked at more than 4,000 Seattle-area residents enrolled in the Adult Changes in Thought (ACT) Study run by Kaiser Permanente Washington Health Research Institute in collaboration with UW. Of those residents, the researchers identified more than 1,000 people who had been diagnosed with dementia at some point since the ACT Study began in 1994.

Once a patient with dementia was identified, researchers compared the average pollution exposure of each participant leading up to the age at which the dementia patient was diagnosed. For instance, if a person was diagnosed with dementia at 72 years old, the researchers compared the pollution exposure of other participants over the decade prior to when each one reached 72. In these analyses, the researchers also had to account for the different years in which these individuals were enrolled in the study, since air pollution has dropped dramatically in the decades since the ACT study began.

In their final analysis, the researchers found that just a 1 microgram per cubic meter difference between residences was associated with 16% higher incidence of dementia. To put that difference into perspective, Shaffer said, in 2019 there was approximately 1 microgram per cubic meter difference in PM2.5 pollution between Pike Street Market in downtown Seattle and the residential areas around Discovery Park.

"We know dementia develops over a long period of time. It takes years -- evendecades -- for these pathologies to develop in the brain, and so we needed to look at exposures that covered that extended period," Shaffer said. And, because of long-running efforts by many UW faculty and others to build detailed databases of air pollution in our region, "we had the ability to estimate exposures for 40 years in this region. That is unprecedented in this research area and a unique aspect of our study."

In addition to extensive air pollution and dementia data for the region, other study strengths included lengthy address histories and high-quality procedures for dementia diagnoses for the ACT Study participants.

"Having reliable address histories let us obtain more precise air pollution estimates for study participants," said senior author Lianne Sheppard, a UW professor of environmental and occupational health sciences and of biostatistics. "These high-quality exposures combined with ACT's regular participant follow-up and standardized diagnostic procedures contribute to this study's potential policy impact."

While there are many factors such as diet, exercise and genetics associated with the increased risk of developing dementia, air pollution is now recognized to be among the key potentially modifiable risk factors. The new UW-led results add to this body of evidence suggesting air pollution has neurodegenerative effects and that reducing people's exposure to air pollution could help reduce the burden of dementia.

"How we've understood the role of air pollution exposure on health has evolved from first thinking it was pretty much limited to respiratory problems, then that it also has cardiovascular effects, and now there's evidence of its effects on the brain," said Sheppard, who this year was awarded the Rohm & Haas Endowed Professorship of Public Health Sciences.

"Over an entire population, a large number of people are exposed. So, even a small change in relative risk ends up being important on a population scale," Shaffer said. "There are some things that individuals can do, such as mask-wearing, which is becoming more normalized now because of COVID. But it is not fair to put the burden on individuals alone. These data can support further policy action on the local and national level to control sources of particulate air pollution."

https://www.sciencedaily.com/releases/2021/08/210804123113.htm

Remember more by taking breaks

Longer breaks during learning lead to more stable activation patterns in the brain.

July 29, 2021

Science Daily/Max-Planck-Gesellschaft

Many of us have experienced the following: the day before an exam, we try to cram a huge amount of information into our brain. But just as quickly as we acquired it, the knowledge we have painstakingly gained is gone again. The good news is that we can counteract this forgetting. With expanded time intervals between individual learning events, we retain the knowledge for a longer time.

But what happens in the brain during the spacing effect, and why is taking breaks so beneficial for our memory? It is generally thought that during learning, neurons are activated and form new connections. In this way, the learned knowledge is stored and can be retrieved by reactivating the same set of neurons. However, we still know very little about how pauses positively influence this process – even though the spacing effect was described more than a century ago and occurs in almost all animals.

Annet Glas and Pieter Goltstein, neurobiologists in the team of Mark Hübener and Tobias Bonhoeffer, investigated this phenomenon in mice. To do this, the animals had to remember the position of a hidden chocolate piece in a maze. On three consecutive opportunities, they were allowed to explore the maze and find their reward – including pauses of varying lengths. "Mice that were trained with the longer intervals between learning phases were not able to remember the position of the chocolate as quickly," explains Annet Glas. "But on the next day, the longer the pauses, the better was the mice's memory."

During the maze test, the researchers additionally measured the activity of neurons in the prefrontal cortex. This brain region is of particular interest for learning processes, as it is known for its role in complex thinking tasks. Accordingly, the scientists showed that inactivation of the prefrontal cortex impaired the mice's performance in the maze.

"If three learning phases follow each other very quickly, we intuitively expected the same neurons to be activated," Pieter Goltstein says. "After all, it is the same experiment with the same information. However, after a long break, it would be conceivable that the brain interprets the following learning phase as a new event and processes it with different neurons."

However, the researchers found exactly the opposite when they compared the neuronal activity during different learning phases. After short pauses, the activation pattern in the brain fluctuated more than compared to long pauses: In fast successive learning phases, the mice activated mostly different neurons. When taking longer breaks, the same neurons active during the first learning phase were used again later.

Reactivating the same neurons could allow the brain to strengthen the connections between these cells in each learning phase – there is no need to start from scratch and establish the contacts first. "That's why we believe that memory benefits from longer breaks," says Pieter Goltstein.

Thus, after more than a century, the study provides the first insights into the neuronal processes that explain the positive effect of learning breaks. With spaced learning, we may reach our goal more slowly, but we benefit from our knowledge for much longer. Hopefully, we won't have forgotten this by the time we take our next exam!

https://www.sciencedaily.com/releases/2021/07/210729122037.htm

Adding color to your plate may lower risk of cognitive decline

July 29, 2021

Science Daily/American Academy of Neurology

A new study shows that people who eat a diet that includes at least half a serving per day of foods high in flavonoids like strawberries, oranges, peppers and apples may have a 20% lower risk of cognitive decline. The research is published in the July 28, 2021, online issue of Neurology the medical journal of the American Academy of Neurology. The study looked at several types of flavonoids, and found that flavones and anthocyanins may have the most protective effect.

Flavonoids are naturally occurring compounds found in plants and are considered powerful antioxidants. It is thought that having too few antioxidants may play a role in cognitive decline as you age.

"There is mounting evidence suggesting flavonoids are powerhouses when it comes to preventing your thinking skills from declining as you get older," said study author Walter Willett, MD, DrPH, of Harvard University in Boston, Mass. "Our results are exciting because they show that making simple changes to your diet could help prevent cognitive decline."

The study looked at 49,493 women with an average age of 48 and 27,842 men with an average age of 51 at the start of the study. Over 20 years of follow up, people completed several questionnaires about how often they ate various foods. Their intake of different types of flavonoids was calculated by multiplying the flavonoid content of each food by its frequency. Study participants evaluated their own cognitive abilities twice during the study, using questions like, "Do you have more trouble than usual remembering recent events?" and "Do you have more trouble than usual remembering a short list of items?" This assessment captures early memory problems when people's memory has worsened enough for them to notice, but not necessarily enough to be detected on a screening test.

The people in the group that represented the highest 20% of flavonoid consumers, on average, had about 600 milligrams (mg) in their diets each day, compared to the people in the lowest 20% of flavonoid consumers, who had about 150 mg in their diets each day. Strawberries, for example, have about 180 mg of flavonoids per 100 gram serving, while apples have about 113.

After adjusting for factors like age and total caloric intake, people who consumed more flavonoids in their diets reported lower risk of cognitive decline. The group of highest flavonoid consumers had 20% less risk of self-reported cognitive decline than the people in the lowest group.

Researchers also looked at individual flavonoids. Flavones, found in some spices and yellow or orange fruits and vegetables, had the strongest protective qualities, and were associated with a 38% reduction in risk of cognitive decline, which is the equivalent of being three to four years younger in age. Peppers have about 5 mg of flavones per 100 gram serving. Anthocyanins, found in blueberries, blackberries and cherries, were associated with a 24% reduced risk of cognitive decline. Blueberries have about 164 mg of anthocyanins per 100 gram serving.

"The people in our study who did the best over time ate an average of at least half a serving per day of foods like orange juice, oranges, peppers, celery, grapefruits, grapefruit juice, apples and pears," Willett said. "While it is possible other phytochemicals are at work here, a colorful diet rich in flavonoids -- and specifically flavones and anthocyanins -- seems to be a good bet for promoting long-term brain health. And it's never too late to start, because we saw those protective relationships whether people were consuming the flavonoids in their diet 20 years ago, or if they started incorporating them more recently."

A limitation of the study is that participants reported on their diets and may not recall perfectly what they ate or how much.

The study was supported by the National Institutes of Health

https://www.sciencedaily.com/releases/2021/07/210729122215.htm

Global dementia cases forecasted to triple by 2050

New analysis shows a decrease in prevalence due to education countered by increase due to heart health risk factors

July 27, 2021

Science Daily/Alzheimer's Association

Positive trends in global education access are expected to decrease dementia prevalence worldwide by 6.2 million cases by the year 2050. Meanwhile, anticipated trends in smoking, high body mass index and high blood sugar are predicted to increase prevalence by nearly the same number: 6.8 million cases. Both according to new global prevalence data reported at the Alzheimer's Association International Conference® (AAIC®) 2021 in Denver and virtually.

With these forecasts incorporated, researchers with the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine reported at AAIC 2021 that they estimate the number of people with dementia will nearly triple to more than 152 million by 2050. The highest increase in prevalence is projected to be in eastern sub-Saharan Africa, North Africa and the Middle East.

"Improvements in lifestyle in adults in developed countries and other places -- including increasing access to education and greater attention to heart health issues -- have reduced incidence in recent years, but total numbers with dementia are still going up because of the aging of the population," said Maria C. Carrillo, Ph.D., Alzheimer's Association chief science officer. "In addition, obesity, diabetes and sedentary lifestyles in younger people are rising quickly, and these are risk factors for dementia."

The U.S. National Institute on Aging estimates people over the age of 65 will make up 16% of the world's population by 2050 -- up from 8% in 2010.

Also reported at AAIC 2021 were two other prevalence/incidence studies. Key findings include:

• Each year, an estimated 10 in every 100,000 individuals develop dementia with early onset (prior to age 65). This corresponds to 350,000 new cases of early onset dementia per year, globally.

• From 1999 to 2019, the U.S. mortality rate from Alzheimer's in the overall population significantly increased from 16 to 30 deaths per 100,000, an 88% increase.

• Among all areas of the U.S., mortality rates for Alzheimer's were highest in rural areas in the East South Central region of the U.S., where the death rate from Alzheimer's is 274 per 100,000 in those over 65.

Global Prevalence of Dementia Expected to Grow Rapidly through 2050

To more accurately forecast global dementia prevalence and produce country-level estimates, Emma Nichols, MPH, a researcher with the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine, and colleagues leveraged data from 1999 to 2019 from the Global Burden of Disease (GBD) study, a comprehensive set of estimates of health trends worldwide. This study also aimed to improve on prior forecasts by incorporating information on trends in dementia risk factors.

Nichols and team found dementia would increase from an estimated 57.4 (50.4 to 65.1) million cases globally in 2019 to an estimated 152.8 (130.8 to 175.6) million cases in 2050. The highest increases were observed in eastern sub-Saharan Africa, North Africa and the Middle East. Their analysis suggested that projected increases in cases could largely be attributed to population growth and aging, although the relative importance of these two factors varied by world region.

What's more, Nichols and team forecasted dementia prevalence attributable to smoking, high body mass index (BMI) and high fasting plasma glucose using the expected relationship between these risk factors and dementia prevalence. They found an increase of 6.8 million dementia cases globally between 2019 and 2050 due specifically to expected changes in these risk factors. Separately and conversely, the researchers found that expected changes in education levels will lead to a decline in dementia prevalence of 6.2 million individuals globally between 2019 and 2050. Taken together, these opposing trends come close to balancing each other out.

"These estimates will allow policymakers and decision makers to better understand the expected increases in the number of individuals with dementia as well as the drivers of these increases in a given geographical setting," Nichols said. "The large anticipated increase in the number of individuals with dementia emphasizes the vital need for research focused on the discovery of disease-modifying treatments and effective low-cost interventions for the prevention or delay of dementia onset."

Recently published in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, Nichols and team used the same data set to estimate that Alzheimer's mortality rates increased by 38.0% between 1990 and 2019.

"Without effective treatments to stop, slow or prevent Alzheimer's and all dementia, this number will grow beyond 2050 and continue to impact individuals, caregivers, health systems and governments globally," Carrillo said. "In addition to therapeutics, it's critical to uncover culturally-tailored interventions that reduce dementia risk through lifestyle factors like education, diet and exercise."

The Alzheimer's Association U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S. POINTER) is a two-year clinical trial to evaluate whether lifestyle interventions that simultaneously target many risk factors protect cognitive function in older adults who are at increased risk for cognitive decline.

Incidence Estimates for Younger Onset Dementia Suggest 350,000 New Cases per Year

Data on younger-onset dementia (YOD), a form of dementia where the onset of symptoms happens before age 65, is extremely limited. To better understand the incidence of YOD, Stevie Hendriks, M.Sc., student at Maastricht University in the Netherlands, and colleagues conducted a systematic literature review of all studies published during the past 30 years that reported figures on how many people developed dementia before the age of 65.

Hendriks and team found that, overall, the global incidence rate was 10 new cases each year per 100,000 persons. They also found incidence increases with age. This suggests that around 350,000 people worldwide develop younger-onset dementia every year. Incidence rates for men and women were similar, and were highest for Alzheimer's disease, followed by vascular dementia and frontotemporal dementia.

"Our findings should raise awareness in healthcare professionals, researchers and policy makers because they show that a significant number of people are newly affected by young-onset dementia every year," Hendriks said. "This shows the need for investment in tailored healthcare for this special patient group and more research into how we can best support but also prevent and treat young-onset dementia."

"People living with younger-onset Alzheimer's face unique challenges when it comes to diagnosis, family, work, finances, future care and -- with the recent FDA action -- possible treatment options. But support and information is available," said Kristen Clifford, Alzheimer's Association chief program officer. "And you have the power to make a new plan and determine how you choose to live your best life with the disease."

Rural Areas of American South Experience Disproportionate Burden of Alzheimer's Mortality

Even though average lifespan has been steadily increasing over the past several decades in the U.S., there is an increasing divergence in mortality rates among urban and rural populations. This discrepancy is likely the result of many health disparities experienced by rural residents compared to their urban counterparts, including lower socio-economic status, higher levels of chronic disease, limited availability of internet services, and less access to health services including primary care.

To specifically understand geographic variations in Alzheimer's disease mortality, Ambar Kulshreshtha, M.D., Ph.D., from Emory University, and colleagues used data from the National Center for Health Statistics to examine trends in Alzheimer's death rates between 1999 and 2019 by urbanization levels.

Kulshreshtha and team found that, from 1999 to 2019, the mortality rate from Alzheimer's in the overall population significantly increased from 16 to 30 deaths per 100,000, an 88% increase. Rural areas across the United States were shown to have higher mortality rates from Alzheimer's compared to urban areas. Those rates were highest in rural areas in the East South Central region at 274 per 100,000 in those 65 years and older, more than three times that of urban areas in the mid-Atlantic region in which mortality rates were the lowest.

"Our work shows that there is an increasing discrepancy in Alzheimer's mortality between urban and rural areas. This discrepancy could be related to, or might be the result of, other urban-rural health disparities, including access to primary care and other health services, socio-economic level, time to diagnosis, and the rising proportion of older Americans living in these areas," Kulshreshtha said. "Identifying and understanding the reasons for these health disparities is critical for allocating key social and public health resources appropriately."

https://www.sciencedaily.com/releases/2021/07/210727171713.htm

Improving air quality reduces dementia risk, multiple studies suggest

July 26, 2021

Science Daily/Alzheimer's Association

Improving air quality may improve cognitive function and reduce dementia risk, according to several studies reported today at the Alzheimer's Association International Conference® (AAIC®) 2021 in Denver and virtually.

Previous reports have linked long-term air pollution exposure with accumulation of Alzheimer's disease-related brain plaques, but this is the first accumulated evidence that reducing pollution, especially fine particulates in the air and pollutants from the burning of fuel, is associated with lower risk of all-cause dementia and Alzheimer's disease.

Both increasing levels of air pollution and increasing cases of dementia are worldwide public health crises. While research has linked air quality and cognition previously, these new data at AAIC 2021 explore how air pollutants might impact dementia and what reducing them might mean for long-term brain health. Among the key findings are:

- Reduction of fine particulate matter (PM2.5) and traffic-related pollutants (NO2) per 10% of the Environmental Protection Agency's (EPA) current standard over 10 years was associated with 14% and 26% reductions in dementia risk, and slower cognitive decline, in older U.S. women. These benefits occurred in women regardless of their age, level of education, the geographic region where they lived and whether they had cardiovascular disease. 

- Reduction of PM2.5 concentration over 10 years was associated with a reduced risk of all-cause dementia in French individuals by 15% and of Alzheimer's disease by 17% for every microgram of gaseous pollutant per cubic meter of air (µg/m3) decrease in PM2.5.

- Long-term exposure to air pollutants was associated with higher beta amyloid levels in the blood in a large U.S. cohort, showing a possible biological connection between air quality and physical brain changes that define Alzheimer's disease.

"We've known for some time that air pollution is bad for our brains and overall health, including a connection to amyloid buildup in the brain," said Claire Sexton, DPhil, Alzheimer's Association director of scientific programs and outreach. "But what's exciting is we're now seeing data showing that improving air quality may actually reduce the risk of dementia. These data demonstrate the importance of policies and action by federal and local governments, and businesses, that address reducing air pollutants."

Air Quality Improvement May Slow Cognitive Decline and Reduce Dementia Risk in Older U.S. Women

Although studies have found that improved air quality is associated with better respiratory health and longer life expectancy, it's unknown if improved air quality can also improve brain health. To investigate this further, Xinhui Wang, Ph.D., assistant professor of research neurology at University of Southern California, and colleagues investigated whether older women living in locations with greater reduction in air pollution may have slower decline in their cognitive function and be less likely to develop dementia.

Wang and team looked at a group of older women (aged 74-92) in the U.S. from the National Institutes of Health-funded Women's Health Initiative Memory Study-Epidemiology of Cognitive Health Outcomes (WHIMS-ECHO) who did not have dementia at the beginning of the study. Participants were followed from 2008-2018 and detailed cognitive function tests were done every year to determine whether they developed dementia. Participants' home addresses were noted and mathematical models were used to estimate the air pollution levels at these locations over time.

The researchers found that, in general, air quality greatly improved over the 10 years before the study began. During a median of six years of follow-up, cognitive functions tended to decline as women aged, as expected. However, for those living in locations with greater reduction per 10% of the EPA's current standard in both PM2.5 (fine particles that are 30 times thinner than a human hair) and NO2 (indicator of traffic-related pollutants), their risk of dementia decreased by 14% and 26%. This was similar to the lower level of risk seen in women two to three years younger.

Benefits were also seen for slower decline in overall cognitive function and memory, similar to women one to two years younger, and on specific tests of working memory, episodic memory and attention/executive function -- cognitive domains with early decline detectable in dementia at the preclinical stage. These benefits were seen regardless of age, level of education, the geographic region where they lived and whether they had cardiovascular disease.

"Our findings are important because they strengthen the evidence that high levels of outdoor air pollution in later life harm our brains, and also provide new evidence that by improving air quality we may be able to significantly reduce risk of cognitive decline and dementia," Wang said. "The possible benefits found in our studies extended across a variety of cognitive abilities, suggesting a positive impact on multiple underlying brain regions."

Reduction of Fine Particulates is Associated with Reduced Risk of Dementia in Older French Adults

In a similarly structured study, Noemie Letellier, Ph.D., postdoctoral scholar at University of California, San Diego, and colleagues worked with the French Three-City Study, a large cohort of more than 7,000 participants aged 65 or older, to investigate the links between air pollution exposure and dementia risk. The researchers observed reduction of PM2.5 concentration between 1990-2000, which was associated with a 15% reduced risk of all-cause dementia and a 17% reduced risk of Alzheimer's disease for every microgram of gaseous pollutant per cubic meter of air (µg/m3) decrease in PM2.5, independent of socio-demographic and health behaviors factors, and APOE genotype.

"These data, for the first time, highlight the beneficial effects of reduced air pollution on the incidence of dementia in older adults." Letellier said. "The findings have important implications to reinforce air quality standards to promote healthy aging. In the context of climate change, massive urbanization and worldwide population aging, it is crucial to accurately evaluate the influence of air pollution change on incident dementia to identify and recommend effective prevention strategies."

Long-Term Air Pollution is Associated with Increased Beta Amyloid Plaques

Accumulation of beta amyloid plaques is one of the hallmarks of Alzheimer's disease. While a relationship between air pollution and increased beta amyloid production has been found in animal and human studies, relatively little is known about the effects of long-term exposure to air pollution on beta amyloid.

Christina Park, doctoral student in the Department of Epidemiology at University of Washington, and colleagues examined associations between exposure to air pollutant levels of fine particulate matter (PM2.5), larger particles (PM10) and nitrogen dioxide (NO2), and levels of Aβ1-40 (one of the major protein components of plaques) in more than 3,000 individuals who were dementia-free at the beginning of the Ginkgo Evaluation of Memory Study. The study evaluated and averaged air pollution levels at participant residential addresses for time periods up to 20 years prior to taking blood tests to measure individuals' beta amyloid.

People who were in the study longer (eight years) showed a strong link between all three air pollutants and Aβ1-40. These are some of the first human data suggesting long-term exposure to air pollutants is associated with higher Aβ1-40 levels in the blood.

"Our findings suggest that air pollution may be an important factor in the development of dementia," Park said. "Many other factors that impact dementia are not changeable, but reductions in exposure to air pollution may be associated with a lower risk of dementia. More research is needed."

https://www.sciencedaily.com/releases/2021/07/210726113936.htm

Think about this: Keeping your brain active may delay Alzheimer's dementia 5 years

July 14, 2021

Science Daily/American Academy of Neurology

Keeping your brain active in old age has always been a smart idea, but a new study suggests that reading, writing letters and playing card games or puzzles in later life may delay the onset of Alzheimer's dementia by up to five years. The research is published in the July 14, 2021, online issue of Neurology, the medical journal of the American Academy of Neurology.

"The good news is that it's never too late to start doing the kinds of inexpensive, accessible activities we looked at in our study," said study author Robert S. Wilson, PhD, of Rush University Medical Center in Chicago. "Our findings suggest it may be beneficial to start doing these things, even in your 80s, to delay the onset of Alzheimer's dementia."

The study looked at 1,978 people with an average age of 80 who did not have dementia at the start of the study. The people were followed for an average of seven years. To determine if they had developed dementia, participants were given annual examinations, which included a number of cognitive tests.

When the study began, people rated their participation in seven activities on a five-point scale. The questions included: "During the past year, how often did you read books?" and "During the past year, how often did you play games like checkers, board games, cards or puzzles?"

Participants also answered questions about cognitive activity in childhood, adulthood and middle age.

Researchers then averaged each person's responses, with a score of one meaning once a year or less and score of five meaning every day or almost every day. People in the group with high cognitive activity scored an average of 4.0 which meant activities several times per week, compared to an average score of 2.1 for those with low cognitive activity, which meant activities several times per year.

During the study follow-up period, 457 people with an average age of 89 were diagnosed with Alzheimer's dementia. People with the highest levels of activity, on average, developed dementia at age 94. The people with the lowest cognitive activity, on average, developed dementia at age 89, a difference of five years. The results were similar when researchers adjusted for other factors that could affect dementia risk, such as education level and sex.

To test the idea that low cognitive activity may be an early sign of dementia, not the other way around, researchers also looked at the brains of 695 people who died during the study. Brain tissue was examined for markers of Alzheimer's like amyloid and tau protein deposits, but researchers found no association between how active they were cognitively and markers of Alzheimer's disease and related disorders in their brains.

"Our study shows that people who engage in more cognitively stimulating activities may be delaying the age at which they develop dementia," Wilson said. "It is important to note, after we accounted for late life level of cognitive activity, neither education nor early life cognitive activity were associated with the age at which a person developed Alzheimer's dementia. Our research suggests that the link between cognitive activity and the age at which a person developed dementia is mainly driven by the activities you do later in life."

A limitation of the study is that it was based on a group of mainly white people who had high levels of education. Further research will be needed to determine if the findings apply to the general population.

The study was supported by the National Institute on Aging.

https://www.sciencedaily.com/releases/2021/07/210714170134.htm

Vocal music boosts the recovery of language functions after stroke

July 9, 2021

Science Daily/University of Helsinki

Research has shown that listening to music daily improves language recovery in patients who have experienced a stroke. However, the neural mechanisms underlying the phenomenon have so far remained unknown.

A study conducted at the University of Helsinki and the Turku University Hospital Neurocenter compared the effect of listening to vocal music, instrumental music and audiobooks on the structural and functional recovery of the language network of patients who had suffered an acute stroke. In addition, the study investigated the links between such changes and language recovery during a three-month follow-up period. The study was published in the eNeuro journal.

Based on the findings, listening to vocal music improved the recovery of the structural connectivity of the language network in the left frontal lobe compared to listening to audiobooks. These structural changes correlated with the recovery of language skills.

"For the first time, we were able to demonstrate that the positive effects of vocal music are related to the structural and functional plasticity of the language network. This expands our understanding of the mechanisms of action of music-based neurological rehabilitation methods," says Postdoctoral Researcher Aleksi Sihvonen.

Listening to music supports other rehabilitation

Aphasia, a language impairment resulting from a stroke, causes considerable suffering to patients and their families. Current therapies help in the rehabilitation of language impairments, but the results vary and the necessary rehabilitation is often not available to a sufficient degree and early enough.

"Listening to vocal music can be considered a measure that enhances conventional forms of rehabilitation in healthcare. Such activity can be easily, safely and efficiently arranged even in the early stages of rehabilitation," Sihvonen says.

According to Sihvonen, listening to music could be used as a cost-efficient boost to normal rehabilitation, or for rehabilitating patients with mild speech disorders when other rehabilitation options are scarce.

After a disturbance of the cerebral circulation, the brain needs stimulation to recover as well as possible. This is the goal of conventional rehabilitation methods as well.

"Unfortunately, a lot of the time spent in hospital is not stimulating. At these times, listening to music could serve as an additional and sensible rehabilitation measure that can have a positive effect on recovery, improving the prognosis," Sihvonen adds.

https://www.sciencedaily.com/releases/2021/07/210709104224.htm