The effects of climate change continue to rise across the globe, with increased occurrences of extreme and intense weather. The consequences not only impact the environment, but the changes pose a significant threat to our health.
In a recent study published by the Journal of American Medical Association, researchers found that people who live in areas of the United States with high levels of particle pollution have a greater risk of dementia. The areas most affected were those with high emissions from agriculture and wildfires, impacting residents who tended to be older and of lower socioeconomic status.
While scientific literature has not uncovered a direct causation, climate and health experts at the University of Colorado School of Medicine understand the impacts of brain health and the changing environment and what must be done to mitigate the effects.
“The full gamut of neurodegenerative diseases — Alzheimer’s, Parkinson’s, ALS — they all have risk factors associated with environmental exposures. We know that exposure to pesticides and herbicides seems to be one of the clearest risks,” says Samantha Holden, MD, vice chair of outpatient neurology services and director of the Memory Disorders Clinic.
The link between environment and brain health
Between 60% and 70% of the risk for dementia is not fully known, but is likely due to a combination of polygenic factors, other comorbidities, and external exposures. However, the remaining 30%-40% is made up of known and defined potentially modifiable risk, Holden says. She further explains that improving factors like maternal health, environmental risks, and toxic exposures could significantly reduce dementia cases when paired with treating comorbidities such as high blood pressure and stress.
“Many brain protection interventions have been focused on the individual, but there has not been enough attention paid to those external environmental factors, which actually start in utero in terms of what your mother is exposed to,” says Holden, associate professor of neurology at the CU School of Medicine.
The connection between air pollution and neurodegenerative diseases remains relatively unexplored, but the correlation between the two is enough that researchers are placing more focus on potential links.
Jay Lemery, MD, professor of emergency medicine and director of the Climate & Health Program at the CU School of Medicine, emphasizes that over the past few decades, climate change and related environmental issues have changed the landscape of both our physical world and our internal environments. It’s a big reason why he developed the Climate & Health Program.
“We know that particulate matter contributes to morbidity and mortality,” explains Lemery. “The basic pathophysiology is that as we breathe in this degraded air from particulate matter, the incidence of heart disease and lung disease goes up, along with other diseases.”
The challenge of making an impact
Understanding the correlation between air quality and brain health is merely the first step. Since the problem of pollution is so closely tied to external factors such as corporate emissions and dependent on larger-scale policy improvements, finding solutions can be daunting. However, there are improvements on an individual level that can prevent and mitigate the effects of air pollution on health.
Lemery suggests utilizing air filters in the home, staying indoors if necessary, and generally being mindful of air quality before exercise and even daily living activities.
“Young, healthy athletes need to pay attention to this, and so do older people who may have cardiac disease or chronic lung disease. They all should be paying attention to the air quality, particularly during spikes where it’s badly degraded,” says Lemery, mentioning the recent fires in Canada, Maui, and Colorado as significant risks contributing to particle pollution. “Wildfires degrade air over huge swaths of the continent — these are not regional phenomena. The effects are becoming more widespread in ways that we haven’t imagined.”
Holden also mentions the need to look at health care from a wider lens and addressing inequities.
“We need to change the health care system,” she says. “We need one that’s more proactive and preventative, instead of waiting for things to go wrong. And we also need to work to change environmental policies."
“A lot of this contributes to the inequities in health care and disease burden, where people of lower socioeconomic status and people in historically excluded or underserved communities are living in areas that are less desirable, whether that’s from things like redlining, exclusion, or other policies that put those people in harm’s way,” Holden explains.
While she reiterates the necessity of prioritizing sleep, stress management, exercise, diet, and blood pressure, Holden acknowledges that climate and health justice are important pieces of the puzzle.