A comprehensive meta-analysis conducted by scientists at Hong Kong Baptist University (HKBU) has found a significant association between exposure to PM2.5, fine particulates of less than 2.5 microns, and neurological disorders such as stroke and Alzheimer’s disease. Neurological disorders are the leading cause of disability and the second leading cause of death worldwide, posing serious challenges to global health.
PM2.5 is typically made up of heavy metals and organic molecules suspended in the air. Some of these tiny particles and soluble components can enter the bloodstream by many pathways, and they can induce inflammation, death of cells and DNA damage.
Systematic reviews and meta-analyses on the association between PM2.5 exposure and neurological disorders have been limited so far, but the HKBU research team, led by Professor Ken Yung of the Department of Biology at HKBU, analysed a total of 1,645 articles published before June 2018. The researchers also identified 80 eligible studies that covered a population of more than 6.33 million people from 26 countries or regions in all continents except Antarctica.
The results revealed that exposure to PM2.5 in general increases the risk of stroke and stroke mortality, with the risk associated with long-term exposure more significant than with short-term exposure. It also showed that the risk of stroke in heavily polluted areas is higher than that in lightly polluted areas. The study also showed that PM2.5 exposure is strongly associated with an increased risk of Alzheimer’s disease, autism spectrum disorder, Parkinson’s disease and dementia.
“More vigorous research endeavours are required before we can fully understand the mechanisms of how PM2.5 causes different types of neurological disorders, based on which we can formulate effective environmental and public health strategies in response,” said Professor Yung.
Professor Ken Yung (right) and Dr Fu Pengfei, Postdoctoral Research Fellow of the Department of Biology of HKBU, found a strong association between PM2.5 and a wide range of neurological disorders.
The findings were published in the journal Science of the Total Environment.
