Environmental features linked to dementia risk and cognitive decline
Story by PsyPost
Estrogen-plus-progestin imbalance and memory loss – Search
People living in greener, more walkable neighborhoods may face a lower risk of developing dementia, while those exposed to more air pollution might face a higher risk, according to a large review of existing studies. The findings, published in Ageing Research Reviews, highlight connections between environmental factors and brain health as people age.
Dementia is a growing global concern, affecting nearly 50 million people worldwide. It encompasses a range of disorders that impair memory, thinking, and daily functioning, including Alzheimer’s disease. With an aging population and no available cure, finding ways to prevent or delay dementia has become a pressing goal in public health.
While many studies have examined genetic and lifestyle factors, researchers are now turning their attention to environmental influences. Previous studies have hinted that elements such as air quality, traffic noise, and neighborhood design may affect brain health, but results have been inconsistent and often based on subjective reports.
To address this gap, a team of researchers conducted a systematic review and meta-analysis. This means the researchers carefully examined and combined data from many previously published studies. A systematic review aims to gather all relevant evidence on a topic, while a meta-analysis uses statistical techniques to combine the results of those studies and provide a clearer picture of how strong the observed effects are. Only studies that used objective measures—such as satellite data, geographic information systems, and pollution monitoring—were included to ensure the most reliable results.
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“My interest in this research topic is because of the urgent global challenge posed by dementia. As dementia affects millions of people and effective treatments remain limited, I was driven to explore modifiable risk factors that could help delay or even prevent cognitive decline,” said study author Linlin Da, a PhD student at the University of Georgia.
“I became particularly interested in investigating the role of the built environment, and how factors such as air pollution, urban design, and the availability of green spaces might influence cognitive health. By utilizing objective measures to assess these environmental exposures, I aimed to address inconsistencies in previous studies and contribute to a clearer understanding of how urban planning and environmental policies could support dementia prevention.”
The researchers searched five major scientific databases and initially identified over 1,800 studies. After a thorough screening process, they selected 54 high-quality studies for their systematic review, 21 of which were also suitable for meta-analysis. The included studies came from around the world, with sample sizes ranging from under 200 to over 63 million individuals, most of whom were aged 60 and older.
These studies measured environmental exposures like fine particulate matter in the air (known as PM2.5), nitrogen dioxide, proximity to green spaces, and access to local services. Outcomes included diagnosed dementia or measures of cognitive decline over time.
The researchers found that people exposed to higher levels of air pollution were more likely to develop dementia. Specifically, exposure to fine particulate matter—tiny particles that can be inhaled into the lungs and bloodstream—was associated with a 9% higher risk. Nitrogen dioxide exposure was linked to a 10% higher risk. Living near major roads, often a source of both air pollution and noise, was also tied to a 10% increase in dementia risk.
In contrast, people living in neighborhoods with more green and blue spaces—such as parks, forests, rivers, or lakes—had a 6% lower risk of developing dementia. These areas were also associated with slower cognitive decline. Neighborhoods with more connected street layouts and better walkability also supported cognitive health, possibly by encouraging physical activity and social engagement. Access to food stores, community centers, and healthcare services was similarly beneficial.
While these associations don’t prove direct cause and effect, they are consistent with what scientists already know about how the environment can affect the brain. Air pollution is known to cause inflammation and oxidative stress in the body, which can harm brain tissue and potentially contribute to dementia. On the other hand, green spaces may help protect the brain by reducing stress, encouraging exercise, and improving sleep—all of which are known to support cognitive health.
The study did have some limitations.
The researchers found considerable variation across the studies they analyzed. This so-called heterogeneity reflects differences in study designs, populations, and how environmental factors were measured. Some factors, like indoor air quality or socioeconomic status, were not always taken into account, and the methods used to estimate environmental exposure may not perfectly reflect individuals’ real-life experiences.
Still, the authors emphasize that their findings provide strong evidence that environmental features play a meaningful role in brain health. By focusing on studies that used objective measurements and following participants over time, the researchers were able to offer a more reliable picture than many past efforts.
Song hopes the findings will help shape future research and public health efforts. “These numbers show that living in a dementia-friendly environment is important to delay or prevent cognitive decline and the onset of dementia,” said Suhang Song, an assistant professor at the University of Georgia.
Urban planning decisions—like adding parks, improving air quality, and making neighborhoods more walkable—may offer a promising path toward protecting cognitive health at the population level. Future research may focus on how to better measure these environmental exposures over time, and how they interact with genetics, lifestyle, and other personal risk factors.
The study, “Objectively measured environmental features and their association with cognition and dementia: A systematic review and meta-analysis,” was authored by Linlin Da, Xia Song, Zimu Jia, Nicholas Gary Lamont Myers, Jin Sun, Jingkai Wei, Daniel Jung, Feiyang Li, and Suhang Song.
What the research says about estrogen loss and memory loss – Search
Estrogen and memory loss are related in the following ways:
Estrogen depletion during perimenopause can cause memory decline. Memory often improves after menopause. Estrogen-plus-progestin therapy doubles the risk of dementia. Estrogen alone increases the risk of dementia by 50% .Women on estrogen-only therapy have a 26% lower risk of dying from Alzheimer’s disease.
Perspective: Estrogen and the Risk of Cognitive Decline: A Missing Choline(rgic) Link? – It can be hard to measure mild memory loss because research is largely dependent on women’s perceptions that they’ve experienced memory loss. Also, memory declines with age, so it can be hard to determine if it’s caused by menopause.
Still, studies on the effect of estrogen on memory support the idea that estrogen depletion during perimenopause causes memory loss, and that memory improves after menopause.
For example, a large 2004 study supports the finding that hormone changes during perimenopause often cause a decline in verbal memory. It found these effects are separate from the natural effects of aging. This study provides the basis for many current studies.
Another four-year studyTrusted Source found that women couldn’t learn as well during perimenopause. After menopause, women returned to the learning levels they demonstrated before perimenopause.
A reviewTrusted Source published in the Journal of Steroid Biochemistry and Molecular Biology also identified reduced memory and thinking skills in women during perimenopause and menopause. The women in the study reported problems especially with forgetfulness and concentration.
The exact effect of estrogen and progesterone loss on the brain is not well understood. It’s believed that estrogen may help the neurotransmitter systems that send signals in brain areas involved in memory and information processing. Many researchers also think that estrogen promotes the growth and survival of neurons, the cells that send electrical impulses. These impulses serve as messages that are crucial for making your brain and nervous system work properly.
What you can do
There are a few things you can do to help keep your memory functioning at its best through this time.
Get good rest
Sleep loss contributes to mood disturbances and depression.
Try these tips to maintain a healthy sleep cycle:
- Maintain a regular sleep schedule, including on the weekends.
- Reduce your caffeine intake.
- Keep your bedroom cool, and consider placing a fan nearby.
- Purchase a cooling pad or pillows with cooling elements.
- Make sure your room is as dark as possible.
- Learn relaxation techniques, such as mindful meditation or yoga.
- Exercise, but not right before bedtime.
- Wear bedclothes made of natural fibers, such as cotton, hemp, linen, or silk.
- Avoid alcohol, smoking, and spicy foods.
- Consider asking your doctor to arrange a sleep assessment.
Eat right
Food that’s bad for your heart may also be bad for your brain. This means that you should limit saturated fats and trans fats found in foods such as fried foods, battered foods, and baked goods.
Try these other tips for eating a healthful diet, as well:
- Eat a diet that’s rich in fruit and vegetables, particularly leafy green vegetables.
- Look for whole-grain products in breads and side dishes.
- 15 Foods With More Omega-3s Than Walnuts
- Choose low-fat dairy options.
- Eat eggs to get the protein and vitamin D you need for bone health.
- Use non hydrogenated oils, such as olive oil, safflower oil, or canola oil.
- Choose products made with unhydrogenated oil if you’re purchasing processed food.
- Limit sweets, especially baked goods and carbonated beverages.
- Limit red meat.
Exercise your body
Exercise stimulates your brain in areas that are critical to memory and information processing. It also improves the functioning of the hippocampus, a part of your brain responsible for different types of memory.
The American College of Sports Medicine recommends that premenopausal and postmenopausal women get at least 30 minutes of moderate exercise per day, five days per week. A combination of aerobic and resistance exercise has the greatest impact.
Aerobic exercise can include:
- walking
- riding your bike
- aerobics classes
- tennis
- the stair machine
- dancing
Resistance exercises include:
- lifting weights
- exercising with a resistance band
- exercises that use your body for resistance, such situps, pushups, and squats
Exercise your brain
Keeping your brain active helps stave off the effects of aging. Try these tips to give your brain a workout.
- Do crossword puzzles and Sudoku.
- Play word games. Matching Spidey Game
- Play online brain games and also quizzes.
- Read books, newspapers, and magazines.
- Learn something new, like a musical instrument or a new language.
- Spend time talking and socializing with family or friends.
When to seek help
It’s normal to be forgetful as you age and go through menopause. Normal occurrences may include losing your keys, forgetting why you entered a room, or having a name slip your mind.
If your menopause symptoms are severe, though, you may want to talk to your doctor about low-dose menopausal hormone therapy (MHT). MHT increases your risk of breast cancer, cardiovascular disease, and gallbladder disease. If you have a history of any of those diseases, you are not a good candidate for MHT. But your doctor may recommend limited use to help control your symptoms.
More serious cases
Be aware of symptoms that may be signs of more serious memory problems, such as:
- repeating questions or comments
- neglecting hygiene
- forgetting how to use common objects
- being unable to understand or follow directions
- forgetting common words
- getting lost in places you know well
- having trouble carrying out basic daily activities
Symptoms such as these warrant a visit to the doctor. The doctor may check for dementia or Alzheimer’s disease. There are many other reasons for memory loss, as well, including:
- medications
- infection
- head injury
- alcoholism
- depression
- overactive thyroid
Your doctor can help you figure out the cause of your memory loss and the best treatment.
Outlook
Researchers agree that memory loss is common in perimenopause, and that it often improves after menopause. Talk to your doctor to create a plan to get you through perimenopause. Keep track of your symptoms and discuss them with your doctor as you progress through perimenopause. As you near menopause, you will hopefully begin to feel better, and your memory will begin functioning more fully.
Estrogen and memory loss are related in the following ways:
- Estrogen depletion during perimenopause can cause memory decline.
- Memory often improves after menopause.
- Estrogen-plus-progestin therapy doubles the risk of dementia.
- Estrogen alone increases the risk of dementia by 50%.
- Women on estrogen-only therapy have a 26% lower risk of dying from Alzheimer’s disease.
Perspective: Estrogen and the Risk of Cognitive Decline: A Missing Choline(rgic) Link? – PMC
US approves first blood test for Alzheimer’s
Credit: Karolina Grabowska from Pexels
The United States on Friday approved the first blood test for Alzheimer’s, a move that could help patients begin treatment earlier with newly approved drugs that slow the progression of the devastating neurological disease.
The test, developed by Fujirebio Diagnostics, measures the ratio of two proteins in the blood. The ratio is correlated with amyloid plaques in the brain—a hallmark of Alzheimer’s that, until now, has been detected only through brain scans or spinal fluid analysis.
“Alzheimer’s disease impacts too many people—more than breast cancer and prostate cancer combined,” said Food and Drug Administration Commissioner Marty Makary.
“Knowing that 10% of people aged 65 and older have Alzheimer’s, and that by 2050 that number is expected to double, I am hopeful that new medical products such as this one will help patients.”
There are currently two FDA approved treatments for Alzheimer’s: lecanemab and donanemab, which target amyloid plaque and have been shown to moderately slow cognitive decline, though they do not cure the disease.
Advocates for the intravenous antibody therapies, including many neurologists, say they can offer patients a few additional months of independence—and are likely to be more effective if started earlier in the disease’s course.
In clinical studies, the blood test produced results largely in line with positron emission tomography (PET) brain scans and spinal fluid analysis.
“Today’s clearance is an important step for Alzheimer’s diagnosis, making it easier and potentially more accessible for US patients earlier in the disease,” said Michelle Tarver of the FDA’s Center for Devices and Radiological Health.
The test is authorized for use in clinical settings for patients showing signs of cognitive decline, and results must be interpreted alongside other clinical information. Alzheimer’s is the most common form of dementia. It worsens over time, gradually robbing people of their memories and independence.
First blood test for Alzheimer’s diagnosis cleared by FDA
FDA greenlights first blood test to help diagnose Alzheimer’s in US
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The first-ever blood test to detect Alzheimer’s disease has been cleared by the U.S. Food and Drug Administration (FDA). In a press release, the agency announced its approval of the first in-vitro diagnostic device, Lumipulse.
The method is intended for early Alzheimer’s detection in adult patients over the age of 55 who are exhibiting signs and symptoms of the disease. The first-ever blood test to detect Alzheimer’s disease has been cleared by the U.S. Food and Drug Administration (FDA).
In a Friday press release, the agency announced its approval of the first in-vitro diagnostic device, Lumipulse.
The method is intended for early Alzheimer’s detection in adult patients over the age of 55 who are exhibiting signs and symptoms of the disease.
ALZHEIMER’S DISEASE COULD BE PREVENTED ANTIVIRAL DRUG ALREADY ON MARKET
The new technology works by detecting amyloid plaques in the brain, a telltale sign of Alzheimer’s.
While PET scans can pick up these plaques, they can be “costly and time-consuming” while exposing patients to radiation, according to the FDA.
The new Lumipulse device reduces the need for a PET scan or other invasive testing, the agency said.
In a clinical study of 499 plasma samples from cognitively impaired adults, the Lumipulse test detected the presence of amyloid plaques in 91.7% of individuals.
The results indicate that the new blood test can “reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease at the time of the test in patients who are cognitively impaired,” the FDA concluded.
The FDA noted the risk of false positive test results from Lumipulse, which could lead to inappropriate diagnosis and unnecessary treatment.
FDA Commissioner Marty Makary, M.D., MPH, wrote in a statement, “Alzheimer’s disease impacts too many people, more than breast cancer and prostate cancer combined.”
“Knowing that 10% of people aged 65 and older have Alzheimer’s, and that by 2050 that number is expected to double, I am hopeful that new medical products such as this one will help patients,” he said.
Center for Devices and Radiological Health Director Michelle Tarver, M.D., PhD, also commented in the press release that nearly seven million Americans are living with Alzheimer’s.
“And this number is projected to rise to nearly 13 million,” she said.
“Today’s clearance is an important step for Alzheimer’s disease diagnosis, making it easier and potentially more accessible for U.S. patients earlier in the disease.”Dementia brain scan
The new technology works by detecting amyloid plaques in the brain, a telltale sign of Alzheimer’s, according to the FDA. (iStock)
The first blood test used to diagnose Alzheimer’s disease was cleared by the Food and Drug Administration for marketing Friday, meaning the laboratory test can be marketed and sold in the U.S., a significant benchmark for detection of the brain disorder that affects 10% of people aged 65 and older.
Key Facts
The diagnostic device that tests blood to help diagnose Alzheimer’s was developed by Fujirebio, a Japanese biotechnology company.
Unlike the newly cleared blood test device, other FDA-authorized or cleared Alzheimer’s tests instead used cerebrospinal fluid samples from patients collected through spinal taps—invasive procedures involving the puncture of the lumbar.
Top FDA official Michelle Tarver said the clearance makes Alzheimer’s diagnosis “easier and potentially more accessible for U.S. patients earlier in the disease.”
An FDA study found the blood test “can reliably predict” the presence of protein conditions associated with Alzheimer’s at the time of the test in cognitively impaired patients.
Big Number
6.7 million. That is the estimated number of Americans who have Alzheimer’s in the U.S., according to the Centers for Disease Control and Prevention, which notes that number is expected to double by 2060.
Surprising Fact
As of now, the lifetime risk for Alzheimer’s for people aged 45 is one in five for women and one in 10 for men.
Key Background
Alzheimer’s diagnosis can be a lengthy process consisting of memory testing, laboratory tests, brain-imaging examinations and more. The Alzheimer’s Association has said the increase in blood tests for the disease could make for earlier and more accurate detection and diagnosis, potentially taking precedent over standard methods that are “expensive, invasive and not always accessible.”
Costs for people with dementia, which Alzheimer’s is a form of, are projected to reach $384 billion this year and nearly $1 trillion by 2050. Up and coming blood tests could also help recruitment for Alzheimer’s clinical trials and cut down wait times for disease assessment. Healthcare experts have contributed the forecasted dramatic increase in Alzheimer’s to an increase in the aging population and improved diagnosis.
Further Reading
Latest Alzheimer’s lab tests focus on memory loss, not brain plaques (NPR)
Alzheimer’s blood test catches 90% of early dementia cases, study finds (CNN)
FDA clears first blood test to detect Alzheimer’s disease. What to know about Lumipulse.
USA TODAY
We’re now closer to being able to diagnose the most common form of dementia with a simple test. The Food and Drug Administration on May 16 said it cleared the first blood test for Alzheimer’s disease.
The blood test is for patients 55 and older who have signs and symptoms of the mind-robbing disease.
The Lumipulse blood plasma test detects a disease hallmark, amyloid plaques, which form in the brains of Alzheimer’s patients.
This approval marks a milestone for patients, their families and doctors, said Howard Fillit, co-founder and chief science officer at the Alzheimer’s Drug Discovery Foundation.
“The ability to diagnose Alzheimer’s earlier with a simple blood test, like we do for cholesterol, is a game changer, allowing more patients to receive treatment options that have the potential to significantly slow or even prevent the disease,” Fillit said.
The blood test is the first of what researchers say could be a new generation of blood tests to replace expensive brain scans and spinal taps now used to diagnose Alzheimer’s, the most common form of dementia. Early diagnosis could allow patients earlier access to FDA-approved drugs to treat Alzheimer’s, an incurable disease that afflicts an estimated 7.2 million older Americans.
In a statement, FDA Commissioner Martin Makary said 10% of people aged 65 and older have Alzheimer’s. “I am hopeful that new medical products such as this one will help patients,” Makary said.
The Lumipulse blood test is made by Japanese company, Fujirebio Diagnostics, which markets a similar Alzheimer’s test that measures cerebrospinal fluid collected by spinal tap. The company did not return messages from USA TODAY asking when the blood test would be available and how much it would cost.
The test calculates a ratio of two proteins, tau and amyloid, found in blood plasma. The ratio approximates a measure of whether a patient has amyloid plaques in their brains − a disease hallmark that is now detected by images from expensive PET scans.
FDA Oks first blood test that can diagnose alzheimer’s disease – Search
In clearing the new blood test, the FDA evaluated a clinical study that measured 499 samples from adults who were cognitively impaired. The study measured how often the blood test detected amyloid plaque compared to existing PET scans or spinal fluid tests.
The blood test picked up nearly 92% of cases detected by scans or spinal fluid. Less than 20% of cases received an inconclusive result, the FDA said. In a news release, the FDA said the test can “reliably predict the presence or absence of amyloid pathology associated with Alzheimer’s disease” in people who are cognitively impaired.
The test is meant to be used at memory clinics or other specialized care settings. Risks include possible false positive or false negative results. Alzheimer’s researchers believe the disease takes root with brain changes before memory and thinking problems surface.
The new generation of blood tests could lead to earlier diagnosis and give patients access to medication. The FDA has approved two Alzheimer’s drugs targeting amyloid plaques in adults with early signs of the disease.
Eli Lilly’s Kisunla and Eisai and Biogen’s drug Leqembi include warnings for MRI-visible injuries, which can include brain swelling and tiny bleeds at the surface of the brain.