Articulated Insight – “News, Race and Culture in the Information Age”
PART OF A SERIES SUPPORTED BY THE PULITZER CENTER
Airborne toxins increase our risk for cognitive disability and disease. We can identify effective responses through the field of exposomics.
The Smog of Mexico City
By 1992, choking traffic and explosive industrial growth hit Mexico City. The United Nations labeled it the world’s most polluted urban area. The high-altitude metropolis sits in a valley. This geography trapped atmospheric filth in a perpetual toxic haze.
Over the next few years, citizens saw the impact in the blanket of smog overhead. They also noticed it in the city’s dogs. The animals became so disoriented they could no longer recognize their human families.
Neuropathologist Lilian Calderón-Garcidueñas studied this phenomenon. She compared the brains of canines and children from the capital to those from cleaner areas. Her findings terrified experts. Childhood air pollution exposure decreases brain volume. It also heightens the risk of brain diseases like Parkinson’s and Alzheimer’s in adulthood.
Lasting Brain Damage
Calderón-Garcidueñas now heads the Environmental Neuroprevention Laboratory at the University of Montana. She notes these damaged brains matter throughout life. They lead to impaired memory and lower intelligence scores.
Other studies show childhood air pollution exposure alters neural circuitry. This affects abilities like decision-making and focus. It also raises the risk of psychiatric disorders.
A Global Air Quality Crisis
The stakes remain enormous for all of us. Air pollution has steadily soared across China, India, and the global south.
According to the United Nations Foundation, “nearly half of the world’s population breathes toxic air each day, including more than 90 percent of children.”
Some 2.3 billion people worldwide cook with solid fuels and open fires. The Foundation adds this makes the problem far worse. The World Health Organization estimates this cooking smoke causes about 3 million premature deaths yearly. Women and children suffer most.
Pollution in the United States
In the United States, average air pollution levels have decreased since lawmakers passed the Clean Air Act in 1970. But millions of Americans still breathe dangerous outdoor air. This air contains inflammation-triggering ozone and fine particulate matter.
Experts call these tiny particles PM2.5. They affect the lungs and heart and are strongly associated with brain damage. Wildfires, like those that burned across Canada recently, produce massive amounts of PM2.5.
A recent study showed another under-recognized source of PM2.5. Pesticides, paints, and personal care products release these particles. They raise the risk for numerous health problems, including strokes.
The Science of Exposomics
Untangling the relationship between air pollution and the brain requires effort. We all face exposure to thousands of contaminants daily. Not everyone develops the same symptoms or diseases from a given pollutant. Genes play a role. Social disparities also matter. Poorer populations usually live closer to factories and toxins.
Researchers sparked a new field called exposomics to understand this. Exposomics studies environmental exposures and their effects on health and disease. It draws on enormous datasets about environmental toxins and human behavior. Researchers use artificial intelligence to make sense of this massive information.
Environmental Translation
Rosalind Wright directs the Institute for Exposomic Research at Mount Sinai. She says our biology translates everything from our external environment. This includes the air we breathe and the stress we face. Constant exposure during critical growth periods strongly harms lifelong brain health.
Impact on Developing Brains
Neuroscientist Megan Herting studies air pollution’s impact on the developing brain at USC. She linked higher PM2.5 exposure to differences in developing brain shapes. It alters cortical thickness and gray matter microstructure. Herting suspects these brain differences are early signs of future cognitive problems.
An international meta-analysis published in 2023 supports her suspicion. The study linked childhood air pollution exposure to depression and suicidal behavior. Brain scans showed changes in neurocircuitry involved in movement disorders like Parkinson’s. They also showed changes in areas responsible for self-control and attention.
Adolescent Vulnerability
In a 2023 study, Herting tracked children entering adolescence. Brains remain highly vulnerable to long-term toxin damage during this sensitive period. The prefrontal cortex develops now to help with decision-making and problem-solving.
Researchers looked at scan data from over 9,000 youngsters. These children experienced air pollution between ages 9 and 10. The team found abnormal changes in connectivity between brain regions. Herting notes these connections allow us to function daily. Scientists still need to learn exactly how these circuitry changes impact us.
The Need for Stricter Standards
Nitrogen dioxide, ozone, and PM2.5 cause these atypical brain circuits. Herting worries most about the small particles. The United States sets stricter limits on fine particulate matter than many countries. However, these limits remain inadequate.
The U.S. Environmental Protection Agency limits annual average PM2.5 levels to 12 micrograms. Health organizations want the agency to lower this to 8 micrograms. Herting warns that America’s air quality changes brain networks during childhood. This increases the risk for later cognitive problems. She plans to follow her young subjects into adulthood to learn more.
Rising Psychiatric Risks
Other research shows air pollution increases psychiatric disorder risks over time. Andrey Rzhetsky and colleagues published related work. They found bad air quality increased rates of bipolar disorder and depression. Early life exposure proved especially harmful.
Rzhetsky used massive datasets from the US and Denmark. He notes that the same environment harms some people but not others. Genetic variants explain this difference. But complex diseases spread faster than genetics alone can explain. PM2.5 remains a strong statistical culprit. We need exposomics to gather more data and solve this puzzle.
Pollution and Parkinson’s Disease
Frances Jensen addressed the American Neurological Society in October 2022. She called environmental exposures a “wake-up call” driving neurodegenerative disease. Jensen noted that aging populations alone cannot explain the sharp rise in Parkinson’s diagnoses. Environmental exposures lurk in the background and continue rising.
Parkinson’s disease is the second-most common neurodegenerative disease. Symptoms generally strike people age 60 and older. Could dirty air explain the increasing worldwide prevalence of Parkinson’s?
Researchers know the disease kills dopamine-producing nerve cells. Environmental health scientist W. Michael Caudle suspects air pollution plays a role. He studies lipopolysaccharides found in bacterial toxins and polluted air. These compounds inflame the liver, which then damages the brain.
Mapping Disease Hotspots
Neuroepidemiologist Brittany Krzyzanowski mapped Parkinson’s risks. She found a major hotspot in the Mississippi-Ohio River Valley. This area features high-density roads, suggesting traffic pollution drives the disease. Manufacturing heavy metals might also cause cell death.
Krzyzanowski published her findings about Parkinson’s disease in 2023. She found people with median air pollution levels face a 56 percent greater risk. Disease frequency rose with pollution levels, but eventually plateaued. She suspects regional differences in particulate matter composition explain this. She will use exposomics to explore these toxic components.
Alzheimer’s and Environmental Factors
Scientists also hunt for connections between environment and Alzheimer’s disease. Caleb Finch studies dementia at USC. Alzheimer’s numbers continue rising globally. Half of people who live to 100 never get dementia. Finch believes air pollution explains some of these differences.
Finch and his colleague Jiu-Chiuan Chen study environmental neurotoxins. People living in highly polluted areas show faster cognitive decline. They also suffer more heart attacks and strokes. The APOE4 genetic variant increases Alzheimer’s risk. However, genes alone do not guarantee the disease. Environmental exposures matter deeply.
Evidence of Cognitive Decline
Chen and Finch published a study in the Journal of Alzheimer’s Disease. They tracked 1,100 men starting around age 56. By age 68, men with high PM2.5 exposures had the worst verbal fluency. High nitrogen dioxide exposure worsened episodic memory. Air pollution clearly interacts with genetic risks.
A separate USC study tracked 2,000 women. When air quality improved, cognitive decline slowed. Lowering exposure to pollutants reduced their brain age by a year.
An international study concluded we can lower dementia risks. We must avoid 12 factors, including air pollution. These factors account for 40 percent of worldwide dementias.
The Alzheimer’s Disease Exposome
Finch proposed the “Alzheimer’s disease exposome” framework. This assesses how environmental factors and genes cause dementia. Environmental changes might prevent disease better than current drugs. Toxins disrupt brain cell repair mechanisms. Stress and obesity cause chronic inflammation, damaging neuron function.
This exposome framework offers a systematic approach. It tracks environmental risks over an individual’s entire lifespan. The tracking starts in the womb and continues through old age.
AI and Future Solutions
Rosalind Wright wanted to trace neurodevelopment problems to pollutants for decades. Massive data amounts overwhelmed early efforts. Now, artificial intelligence makes high-precision research possible. Wright uses machine learning to analyze giant datasets. She tracks exact residential locations and daily pollutant encounters.
This data breakdown shows which factors drive specific risks. It helps people target efforts to reduce dangerous exposures. Exposomics helps tailor prevention and intervention strategies. Scientists now use special silicone bracelets to track personal pollutant exposure.
Empowering Individual Health
Wright also studies past toxin encounters using hair strands and baby teeth. She reminds us that humans are resilient. Problems only arise when chronic exposures overwhelm our adaptation abilities. We cannot fix everything. But knowing more empowers us to intervene and balance our health.
Tools for Readers: Optimize Your Exposome
We can protect ourselves from pollution and toxins. Researchers reporting in Biochemical Journal say optimizing our exposome impacts longevity. Try these practical strategies:
Educate Yourself: Learn how your environment impacts your health. Make informed decisions to improve your healthy aging.
Enhance Diet: Eat bioactive nutrients that fight oxidative stress. Try turmeric, leafy greens, tomatoes, and berries.
Promote Gut Health: Eat high-fiber foods, prebiotics, and probiotics like yogurt.
Reduce Harmful Exposures: Limit exposure to dirty air, smoke, and UV radiation. Use air purifiers and apply sunscreen.
Exercise Regularly: Physical activity reduces inflammation and enhances mental health.
Manage Stress: Chronic stress accelerates aging. Practice mindfulness, meditation, and get adequate sleep.
Build Community: Strong social ties improve resilience and mental health.
#PollutedMinds #MentalHealthMatters #EnvironmentalToxins
