RSS Feed Print
Air pollution and Alzheimer's disease
Lane Simonian
Posted: Sunday, August 9, 2015 5:40 PM
Joined: 12/12/2011
Posts: 4855

There have been several studies suggesting a link between air pollution and Alzheimer's disease but this is the most definitive one yet.

Now, Swedish researchers have uncovered another dangerous side effect of extensive air pollution. The study published in the journal Environmental Health Perspectives suggests that people who live in homes exposed more heavily to pollution run a 40 percent greater risk of developing Alzheimer's disease and vascular dementia than those who live in areas with cleaner air.

"In total, about 16 percent of all the cases of dementia in the study might have been caused by exposure to pollution," researcher Bertil Forsberg said describing the results as "sensational."

Researchers at the Umea University studied nearly 2,000 people over a 15-year span while simultaneously tracking traffic patterns in the northern Swedish city of Umea. All participants were 55 or older and free of any disease symptoms when the study began.

The researchers established the elevated risk having controlled for factors such as age, education level, lifestyle and body fat. While previous research linked air pollution to cancer, asthma and respiratory diseases, academics have in recent years begun to probe how air quality affects the brain. "We know that very small particles can enter the brain through the olfactory nerve and cause direct damage," Forsberg said.

Inhalation through the nose is one of the most direct routes by which environmental toxins (such as various air pollutants and industrial solvents) can enter the hippocampus and damage that region of the brain (which is most affected by Alzheimer's disease).

Several toxins damage the oflactory receptor--this is one of the reasons why the lose of smell is sometimes a harbinger to Alzheimer's disease. The olfactory receptor is a g protein-coupled receptors. Other g protein-coupled receptors damaged in Alzheimer's disease are muscarinic acetylcholine receptors (short-term memory), melatonin (sleep), serotonin (mood), oxytocin (social recognition), and dopamine (alertness).

The most direct route to reversing the damage to these receptors is also through the nose via direct inhalation aromatherapy.

Lane Simonian
Posted: Sunday, August 9, 2015 5:53 PM
Joined: 12/12/2011
Posts: 4855

In some sense even better:

One researcher discovered that dogs in heavily polluted Mexico City showed many of the same symptoms as people suffering from dementia.

Dr. Lilian Calderón-Garcidueñas, lead investigator of the studies, noted that some dogs exposed to Mexico City air began to exhibit "decrements of attention and activity." Caretakers of other dogs "were aware of alterations of sleep patterns and barking," she wrote. Some "reported transient episodes during which the dogs failed to recognize [them]." Inside their brains, Calderón-Garcidueñas found dramatic tissue damage—the cells in the dogs' olfactory-processing center were dying, with the scars of disease traceable out to the nose itself—that was strangely reminiscent of the damage that sometimes appears in an entirely different study population: Alzheimer's and Parkinson's patients.
Domesticated dogs have an exquisite sense of smell; they possess as many as 220 million olfactory neurons, while humans are thought to have between 5 million and 12 million. Dogs are also one of only a handful of animal species known to naturally develop Alzheimer's-type dementia. What Calderón-Garcidueñas discovered more than a decade ago may prove to be the missing element in a long-standing theory of neurodegenerative disease origin. For reasons poorly understood, degenerative diseases like Alzheimer's and Parkinson's often reveal themselves in humans through early breakdowns in the olfactory system. Degenerative disease sufferers lose some of their sense of smell so predictably, and so long before more overt symptoms manifest, that doctors sometimes use smell tests as a diagnostic tool. As a result, many neurologists have long suspected that these disorders might be caused by foreign substances that we inhale through our noses. The most recent studies have looked at the most common of these substances: particle pollution.

For those interested, read the whole article it is fascinating.

Posted: Wednesday, August 12, 2015 8:31 PM
Joined: 9/12/2013
Posts: 3579

lane - I heard an interview with this guy and thought you might find his interest in fungi. Paul Stamets. Deep and broad thinker, reminds me of you, your interests, and the help you provide us here.

This is a link to his work with fungi as planet healer. "The future is fungi: how to save the planet"


I found youtube a great friend to sleeplessness. Have been going through a class lecture series given by a professor on human biology at Stanford.

For anyone who wants to be in your own world there are endless videos on so many subjects. I have headphones, open a window and stretch out on the bed - I usually drift away and have to go back a bit to listen fully, sometimes I play the whole thing over if it is a lot of information.

Deep relaxation for my brain.

Lane Simonian
Posted: Friday, August 14, 2015 10:22 PM
Joined: 12/12/2011
Posts: 4855

A fascinating talk--thank you for sharing it with me, alz+.

I found this review of the possible use of medicinal mushrooms for neurodegenerative diseases tonight.

The Bioactive Compounds in Medicinal Mushrooms have Potential Protective Effects against Neurodegenerative Diseases Tongtong Xu1 and Robert B. Beelman2*

ABSTRACT The Comprehensive and Alternative Medicine (CAM) to treat Neurodegenerative Diseases (NDs) has attracted attention from healthcare professionals and scientific researchers recently. Although in its early research stage, a good number of studies have been performed to investigate the potential preventive or even therapeutic effects of some medicinal mushrooms on NDs. We reviewed recent scientific publications reporting the extraction and identification of the bioactive compounds in medicinal mushrooms commonly used in Asian countries for their potential protective effects against NDs. Five medicinal mushrooms - Hericium erinaceus, Termitomyces albuminosus, Ganoderma lucidum, Dictyophora indusiata, Mycoleptodonoides aitchisonii- have been covered in this review. In vitro, in vivo, and clinical studies have been conducted to confirm the potential protective effects of these compounds against neurodegenerative diseases. Because of the limited research, no clear mechanisms of the preventive actions can be proposed. More animal and human studies are needed in the future to confirm the anti-neurodegenerative effects and understand the mechanism of the protective action of these bioactive compounds.

Knowledge--especially when we are broadly open to it-- is a wonderful thing.

Lane Simonian
Posted: Tuesday, October 4, 2016 11:56 PM
Joined: 12/12/2011
Posts: 4855

There is a followup story on the relationship between air pollution and Alzheimer's disease from the researchers in Mexico City.  The key points are nicely highlighted in the study and presenting them here may be quite helpful in understanding the disease.

Chocolate, Air Pollution and Children's Neuroprotection: What Cognition Tools should be at Hand to Evaluate Interventions?

Long-term exposure to ozone (O3) and fine particulate matter (PM 2.5) above the current US EPA standards is associated with increased risk of AD (Jung et al., ).

Extensive neuroinflammation, breakdown of the neurovascular unit, oxidative stress, and hallmarks of Alzheimer disease pathology are present in the brains of Mexico City children and young adults with chronic yearlong exposures to high levels of O3 and PM2.5.

Cocoa and neuroprotection


Cocoa's beneficial neural effects include the impact on endothelial function and their positive effects on insulin resistance. There is a knowledge gap in the potential beneficial and detrimental effects of long term administration of cocoa in clinically health young urbanites.


And from another study:

 2003 Apr 11;140-141:125-32.

Defenses against peroxynitrite: selenocompounds and flavonoids.


The inflammatory mediator peroxynitrite, when generated in excess, may damage cells by oxidizing and nitrating cellular components. Defense against this reactive species may be at the level of prevention of the formation of peroxynitrite, at the level of interception, or at the level of repair of damage caused by peroxynitrite. Several selenocompounds serve this purpose and include selenoproteins such as glutathione peroxidase (GPx), selenoprotein P and thioredoxin reductase, or low-molecular-weight substances such as ebselen. Further, flavonoids, such as (-)-epicatechin, which occurs in green tea or cocoa as monomer or in the form of oligomers, can contribute to cellular defense against peroxynitrite.

Now peroxynitrite scavengers will also prevent the formation of beta amyloid and tau tangles and remove amyloid plaques and tau tangles via de-nitration so to the extent that beta amyloid and tau tangles contribute to Alzheimer's disease that problem is addressed as well.  The unfortunate thing is that it takes a lot of money to test particular peroxynitrite scavengers for the treatment of Alzheimer's disease.

Lane Simonian
Posted: Wednesday, February 1, 2017 1:26 PM
Joined: 12/12/2011
Posts: 4855

More evidence that air pollution increases the risk for Alzheimer's disease:

With environmental regulations expected to come under heavy fire from the Trump administration, new research offers powerful evidence of a link between air pollution and dementia risk.

For older women, breathing air that is heavily polluted by vehicle exhaust and other sources of fine particulates nearly doubles the likelihood of developing dementia, finds a study published Tuesday. And the cognitive effects of air pollution are dramatically more pronounced in women who carry a genetic variant, known as APOE-e4, which puts them at higher risk for developing Alzheimer’s disease.

In a nationwide study that tracked the cognitive health of women between the ages of 65 and 79 for 10 years, those who had the APOE-e4 variant were nearly three times more likely to develop dementia if they were exposed to high levels of air pollution than APOE-e4 carriers who were not.

Lane Simonian
Posted: Sunday, September 16, 2018 9:51 AM
Joined: 12/12/2011
Posts: 4855

Another study linking air pollution to Alzheimer's disease:

Researchers at ASU link air pollution to Alzheimer's disease

The size of particulates smaller than 2.5 microns in diameter allows those particulates to remain airborne for long periods, to penetrate buildings, to be inhaled easily and to reach and accumulate within brain tissue, the researchers write. They cite other studies that show the accumulation of particulates in the brain can cause neuroinflammation, which is associated with symptoms of dementia.

The researchers' work, which began in 2015, was data-based. They studied 15 years of health records for nearly 7 million American adults ages 65 and older. The economists then tracked the onset of dementia in patients and compared that with data on cumulative residential exposure to fine-particulate air pollution, also known as PM2.5. 

Still unanswered questions remain, including the biology of how fine-particulate pollution gets into the brain and what it does once it's here.

The easiest route of particulate matter to the brain is through the nose.

Just how the fine airborne particles might travel from a rodent’s nasal cavity to its brain is a mystery. But a research team led by Günter Oberdörster at the University of Rochester in New York has used traceable, radioactive specks of elemental carbon to demonstrate that inhaled particles smaller than 200 nanometers can get through the delicate tissues lining a rodent’s nasal cavities, travel along neurons, and spread as far as the cerebellum, at the back of the brain, triggering an inflammatory reaction. 

Particulate matter like many other toxins (including other air pollutants) stimulate g protein-coupled proteins which in turn leads to the production of peroxynitrite.

The Role of MAPK Pathways in Airborne Fine Particulate Matter-Induced Upregulation of Endothelin Receptors in Rat Basilar Arteries [endothelin receptors are g protein-coupled receptors]

Role for endothelin-1-induced superoxide and peroxynitrite production in rebound pulmonary hypertension associated with inhaled nitric oxide therapy.


Peroxynitrite in turns reduces the synthesis of acetylcholine (which is needed for the retrieval of short-term memory), causes DNA damage and inflammation, prevents the regeneration of neurons, and causes the death of neurons.

Alzheimer's disease may then be deceptively simple: all toxins broadly defined that poison the brain make a person more at risk for the disease.  The brain's own antioxidant systems are disabled during the course of the disease, and one then needs to try to substitute for the depleted antioxidants with outside antioxidant.

Posted: Saturday, September 22, 2018 5:55 AM
Joined: 4/6/2014
Posts: 573

Lane, I started a 12 day video series that started yesterday from a email I received  from Dr. Pearlmutter. It's free and they send you a link each morning for the next video. Everyday the video is presented by a different Doctor who is a expert in dementia and on a different subject. In yesterdays introduction video they were talking about how bad mole in your home can be for your home. They also said that Amyloid Plaque is not the cause of Alzheimers and the drug companies are barking up the wrong tree.  Last thing  I will mention is that they also said is that there is not just one cause of Alzheimers.
Lane Simonian
Posted: Saturday, September 22, 2018 10:04 AM
Joined: 12/12/2011
Posts: 4855

Thanks, Don.  I have read some articles by Dr. Perlmutter, but have not seen the series.  I will try to look into it.

I think all of this is correct: bad mold is a serious health threat, amyloid plaques do not cause Alzheimer's disease, and there are many different causes of Alzheimer's disease.  If you don't mind, post any other findings you find interesting and important from the videos.

Lane Simonian
Posted: Sunday, February 2, 2020 9:38 AM
Joined: 12/12/2011
Posts: 4855

Here are a couple of more interesting studies on this topic:

Living near major roads linked to risk of dementia, Parkinson's, Alzheimer's and MS

Researchers from the University of British Columbia analyzed data for 678,000 adults in Metro Vancouver. They found that living less than 50 metres from a major road or less than 150 metres from a highway is associated with a higher risk of developing dementia, Parkinson's, Alzheimer's and MS -- likely due to increased exposure to air pollution.

The researchers also found that living near green spaces, like parks, has protective effects against developing these neurological disorders.

Do World Trade Center Responders Get Early Onset Plaques and Tangles?

As might be expected, their cognitive impairment correlated with PTSD [post-traumatic stress disorder] symptoms and with the amount of their exposure to toxic dust. However, preliminary plasma analysis and PET scans also suggest accumulation of amyloid and tau pathology in the brain, although not necessarily distributed in a typical Alzheimer’s regional pattern...

Sam Gandy at Mount Sinai in New York is a co-author on Clouston’s papers. He suspects inhaled neurotoxins are the culprit behind early cognitive decline in this population. Gandy wrote to Alzforum that Lung-Chi Chen at New York University Langone Medical Center injected dust from the WTC site into the nasal passages of mice and subsequently observed intense neuroinflammation and elevated Aβ in these animals...

From Sam Gandy's comment to article:

Tuck Finch and I share (with Clouston et al.) the suspicion that this WTCFR-PTSD-dementia complex is due to one or more inhaled neurotoxins. Relevant to this story is a study by Lung Chi Chen and his graduate student Michelle Hernandez, who acquired dust from the WTC site and introduced it intranasally into mice. They noted that the mice developed intense neuroinflammation and elevated Aβ levels. To my knowledge, no one has yet established a pathway where an inciting event acts first through inflammation and only later leads to accumulation of secondary plaques and tangles, but this is the sort of thing we have been pondering.

I believe that this is the rule rather than the exception, though.  Without triggering factors that produce oxidative stresss there are no amyloid oligomers and very little hyperphosphorylated tau and neuroinflammation.  There are so many risk factors for Alzheimer's disease that sometimes it is impossible to remove them all or they have already caused their damage to the brain, but find the right antioxidants and the disease can largely be stabilized during its early stages and can be slowed down even during the very late stages.

Posted: Wednesday, February 5, 2020 11:13 AM
Joined: 11/27/2019
Posts: 56

I'm sure increased inflammation from indoor and outdoor pollution, some foods in high quantities (maybe also the pesticides) plays a role. It's good to know for people who want to decrease their risks and work on prevention. 

Lane Simonian
Posted: Wednesday, February 5, 2020 11:25 AM
Joined: 12/12/2011
Posts: 4855

Yes, all of this plays a role.  Here's one on pesticides as a risk factor for Alzheimer's disease. (highly technical, but the abstract and conclusion hit the key points).

Lane Simonian
Posted: Friday, November 20, 2020 11:01 PM
Joined: 12/12/2011
Posts: 4855

More evidence that air pollution inceases the risk for Alzheimer's disease.

Does air pollution increase women’s risk of dementia?

High levels of fine particle pollution are associated with brain shrinkage patterns common in Alzheimer’s disease, a USC study finds.

Older women who live in locations with high levels of air pollution may have more Alzheimer’s-like brain shrinkage than women who live in places with cleaner air, according to a new USC study.

Researchers looked at fine particle pollution and found that breathing in high levels of this kind of air pollution was linked to shrinkage in the areas of the brain vulnerable to Alzheimer’s disease. The findings suggest that further tightening of air quality standards could potentially reduce the risk of dementia in older populations.