Even brief exposure to air pollution can increase the risk of Parkinson’s disease and other neurological diseases, concludes a Korean study.
The study, “Short-term air pollution exposure aggravates Parkinson’s disease in a population-based cohort,” appeared in the journal Scientific Reports.
Various environmental factors contribute to the pathology of Parkinson’s, but air pollution is apparently crucial in triggering inflammation and oxidative stress — two damaging mechanisms associated with neuronal loss in this disease affecting the central nervous system (CNS).
“Recent experimental studies have shown that air pollutants cause neuro-inflammation, CNS oxidative stress, dopamine neuron damage, blood-brain barrier damage and cerebrovascular impairment, which indicate potential biological pathways for neurological diseases,” researchers wrote.
In fact, scientists have linked the rising incidence of Parkinson’s to annual increases in airborne metal concentrations, very long-term exposure (more than 20 years) to nitrogen dioxide (NO2) and yearly increases in small-size air pollutants such as PM10 and PM2.5 among non-smoking women.
Whether short-term air pollution exposure, for days or weeks, can also aggravate Parkinson’s remained elusive.
To find out, researchers used medical records of the National Health Insurance Service–National Sample Cohort to investigate the association of short-term exposure to air pollution components such as PM2.5, NO2, sulfur dioxide (SO2), ozone (O3) and carbon monoxide (CO) with the incidence of Parkinson’s aggravation in South Korea’s capital city, Seoul, between 2002 and 2013.
Aggravation cases were those in which patients had emergency hospital admissions due to Parkinson’s. Researchers also compared pollutants concentrations on case and control days.
The results showed a significant association between an eight-day exposure to increases in air pollution in PM2.5, NO2 and CO and Parkinson’s aggravation. This association was stronger in women and older patients (aged 65–74), and during cold season, although not significantly.
In South Korea, the number of Parkinson’s patients is rising rapidly with 24,300 new cases between 2010 and 2014. In 2014 alone, the disease cost Koreans some $222 million.
“Overall, the findings of this study, involving a representative population-based cohort, suggest that short-term exposure to air pollution may increase the risk of [Parkinson’s disease] aggravation,” researchers concluded. “Our results can serve as the basis for further studies on the short-term association between air pollution and neurological diseases, and for policy-making to mitigate air pollution and reduce neurodegenerative health effects in our aging society.”