Long-term exposure to PM2.5 increases risk of stroke: Chinese study

Long-term exposure to PM2.5, tiny particulate matter less than 2.5 microns in diameter that can enter deep into the lungs, increases the risk of stroke among Chinese adults, according to a study which highlights the chronic health effects of air pollution.

Air pollution, especially the rising level of PM2.5, is a major global environmental and public health issue.

Researchers from Fuwai Hospital under the Chinese Academy of Medical Sciences evaluated the association between long-term exposure to PM2.5 and stroke incidence based on data collected from more than 117,000 Chinese adults, state-run Xinhua news agency reported on Friday.

The research was published in the British Medical Journal.

The research team used satellite remote sensing technology to assess PM2.5 exposure for each subject during the period from 2000 to 2015. The long-term average PM2.5 concentration at participants' residential addresses was 64.9 micrograms per cubic meter.

The research showed that compared with the population with low exposure to PM2.5 (less than 54.5 micrograms per cubic meter), the risk of stroke increases by 53 per cent for the population living in an environment with PM2.5 concentration above 78.2 micrograms per cubic meter for an extended period.

The general risk of stroke rose by 13 per cent with a long-term increase of 10 micrograms per cubic meter of PM2.5 concentration.

The research also discussed the pathogenic mechanism of air pollutants leading to different types of stroke.

Gu Dongfeng, the lead researcher, said the research provides new evidence that PM2.5 is an important risk factor for stroke development in China.

These findings could provide a reference for the policy-making on air pollution and stroke prevention, Gu said, adding that the team will continue investigating the chronic health effects of air pollution with a larger sample size, the report said.

Pollution in China is one aspect of the broader topic of environmental issues in China. Various forms of pollution have increased as China has industrialised, which has caused widespread environmental health problems.

A 2015 study from the non-profit organisation Berkeley Earth estimated that 1.6 million people in China die each year from heart, lung and stroke problems because of polluted air.