(HealthDay News) — Higher exposure to air pollution increases the risk for Parkinson’s disease (PD), according to a study published online Sept. 16 in JAMA Network Open.
Brittany Krzyzanowski, Ph.D., from the Barrow Neurological Institute in Phoenix, and colleagues assessed whether air pollution is associated with an increased risk for PD and clinical characteristics of PD. The analysis included data from 346 patients with PD and 4,813 matched controls participating in the Rochester Epidemiology Project (1998 to 2015).
The researchers found that greater exposure to particulate matter with a diameter of <2.5 μm (PM2.5) was associated with increased PD risk, and this risk was greatest for populations within metropolitan cores (odds ratio [OR], 1.23) for the top quintile of PM2.5 exposure versus the bottom quintile. An increased risk for PD was also seen with greater nitrogen dioxide (NO2) exposure, when comparing the top quintile to the bottom quintile (OR, 1.13). Exposure to air pollution was associated with an increased risk for akinetic rigid presentation (OR per each 1-μg/m3 increase in PM2.5, 1.36). Among individuals with PD only, higher PM2.5 exposure was associated with a greater risk for developing dyskinesia (hazard ratio [HR] per 1-μg/m3 increase in PM2.5, 1.42), as was increased NO2 exposure (HR per 1-μg/m3 increase in NO2, 1.13).
“Importantly, in 2024, the U.S. Environmental Protection Agency reduced the annual PM2.5 standard from 12 μg/m3 to 9 μg/m3 due to growing evidence of negative health effects at levels below the previously set standard,” the authors write. “Our study not only supports the findings that led to this change, but suggests that the upper limit should be lowered to 8 μg/m3.”
One author disclosed ties to the pharmaceutical industry.
What is Parkinson’s disease (PD)?
Parkinson’s disease, a neurodegenerative disorder characterized by tremors, stiffness, and slow movement, is a complex condition influenced by a combination of genetic and environmental factors. While genetic predisposition plays a significant role, emerging research suggests that environmental exposures can also contribute to the development and progression of this disease.
How does the environment influence Parkinson’s disease?
One of the most extensively studied environmental factors linked to Parkinson’s is exposure to toxins. Pesticides, herbicides, and fungicides have been implicated as potential risk factors. Studies have consistently shown higher rates of Parkinson’s disease among individuals who work in agriculture or have been exposed to these chemicals. For instance, exposure to the herbicide paraquat has been associated with an increased risk of developing Parkinson’s, particularly in individuals with genetic susceptibility.
Heavy metals, such as manganese and iron, have also been implicated as potential environmental risk factors. Exposure to these metals, often through occupational or environmental sources, can lead to oxidative stress and damage to neurons in the brain. Individuals working in certain industries, such as mining or welding, may be at a higher risk due to their exposure to these metals.
Air pollution is another environmental factor that has been linked to Parkinson’s disease. Exposure to particulate matter, a type of air pollution, has been shown to increase the risk of developing the disease. This may be due to the ability of particulate matter to cross the blood-brain barrier and induce oxidative stress in brain cells.
It is important to note that the relationship between environmental factors and Parkinson’s disease is complex and not fully understood. While these factors may increase the risk of developing the disease, they do not guarantee that an individual will develop it. Genetic susceptibility and other factors likely play a role as well.
Furthermore, the impact of environmental factors on Parkinson’s disease may vary depending on individual differences, such as genetics and lifestyle. Some individuals may be more susceptible to the effects of certain toxins or pollutants than others. Additionally, factors such as diet, exercise, and stress management may also influence the development and progression of the disease.