NEW DELHI: Exposure to particulate matter (PM 2.5) can heightens the risk of people developing high blood pressure and hypertension, a new study published in the Journal of the American Heart Association has said.
The study, conducted by Indian scientists at the Centre for Chronic Disease Control (CCDC) and Public Health Foundation of India in collaboration with Harvard T.H. Chan School of Public Health, investigated the association between the exposure to ambient particulate matter (PM2.5)–a marker of air pollution–and blood pressure and incident hypertension in Delhi.
Scientists found a higher average systolic BP i.e. 1.8 mm Hg and 3.3 mm Hg in monthly and annual exposures. Positive but less pronounced associations were also observed for diastolic blood pressure.
The study found that average PM2.5 over one, 1.5 years, and 2 years increased the risk of developing hypertension by 50%, 60%, and 20%, respectively. These results were also found to be stronger in study participants with higher waist-to-hip ratios, which is an indicator of central obesity.
The study was carried out in a cohort of 5,300 individuals recruited across different parts of Delhi and followed for 7 years (2010-2016) with annual questionnaire surveys and alternate year biological sample collection.
Major sources of PM2.5 in Delhi include local sources such as traffic, power plants, industries, and regional sources of pollution such as agricultural crop burning in the neighbouring states. The paper assessed daily ambient PM2.5 using a machine learning based predictive model that included myriad data sources such as ground monitor data from the Central Pollution Control Board (CPCB) and Delhi Pollution Control Committee (DPCC), satellite observations, meteorology, land use variables and emissions inventories. Blood pressure was assessed longitudinally at three time points within the cohort over the 7-year period.
“In India, there is very little or no evidence linking the exposure of ambient particular matter (PM2.5), as a marker of air pollution with hypertension,” said Prabhakaran, vice president, Research and Policy, PHFI, also executive director, CCDC and the lead Investigator of the project said.
A Lancet report released in 2019 said more than five lakh people died prematurely in India in 2016 due to dangerous levels of outdoor air pollution.