Long-term exposure to ambient fine particulate matter (PM2.5), a ubiquitous air pollutant, is linked to an increased risk of cardiovascular diseases (CVD) in China, according to new research published today in the journal Environmental Science and Technology
Ambient PM2.5 pollution is considered to be a leading environmental risk factor for global health. However, the current understanding on its health impact was based primarily on studies in Western high-income countries with relatively low air pollution, whereas evidence from low- and middle-income countries has been limited. The study, led by researchers from Oxford Population Health, UK and Fudan University and Peking University, China found new evidence that higher annual average exposure to ambient PM2.5 was associated with higher risks of total and cause-specific hospitalisation and death from CVD, including ischaemic heart disease, stroke, and heart failure.
The authors analysed data from the China Kadoorie Biobank. They adopted a state-of-the-art machine learning approach to estimate annual average PM2.5 concentration across China, at a 1 x 1 km2 spatial resolution. The participants were followed for a median of 9.8 years until 2017, during which over 50,000 participants were hospitalised for ischaemic heart disease and over 57,000 participants were hospitalised for stroke.
After accounting for known confounders such as age, sex, education, and smoking, they found a positive and linear association between long-term exposure and CVD risk, whereby each 10 µg/m3 higher annual average PM2.5 exposure was associated with a 4% higher risk of total CVD. The study also found suggestive evidence of certain subgroups as slightly higher risk, including men, those with higher household income, and among those using solid fuels for heating.
While the study is one of the largest to date to investigate the link between PM2.5 exposure and CVD in China, the authors note the challenges in accurately assessing individuals’ personal PM2.5 exposure even based on the best available data. Further investment and effort is needed to obtain more reliable assessment of air pollution exposure.