Heart disease patients at greater risk from air pollution, finds new study

Poor air quality increases health risks significantly for heart patients, as their bodies struggle to cope with inflammation triggered by pollution, found a recent study presented at the American Heart Association’s 2024 Scientific Sessions in Chicago.

Conducted by researchers at Intermountain Health in Salt Lake City, Utah, the study showed that two inflammatory markers—CCL27 and IL-18—rise sharply in heart patients during pollution spikes, but not in individuals without heart disease.

This finding has crucial implications for India, where cardiovascular diseases are a leading cause of death, and air pollution remains a persistent challenge. India’s cities often record PM2.5 levels many times higher than the benchmarks observed in the study, exacerbating risks for vulnerable populations.

“These biomarkers rose in response to air pollution in people who already had heart disease, but not in patients who were heart disease-free,” explained Dr Benjamin Horne, the study’s principal investigator. “This shows that heart failure patients are less equipped to cope with environmental changes.”

The research, conducted in collaboration with Stanford University and the Harvard School of Public Health, involved analysing blood samples from 44 patients with heart disease and 35 individuals without heart disease. The study found that on days of high pollution, patients with a risk of heart failure consistently exhibited elevated levels of the inflammatory markers, while healthy individuals showed no significant changes.

India’s pollution levels, especially in urban areas, far exceed the PM2.5 concentrations examined in the study, which ranged from 7 to 20 micrograms per cubic metre (μg/m³). In cities like Delhi, levels often soar due to vehicular emissions, industrial pollutants, and seasonal phenomena such as stubble burning and festive fireworks.

“Heart failure patients are not as capable of responding to acute inflammation as healthy individuals, making them especially vulnerable during pollution spikes,” added Dr Horne. The study recommends heart disease patients take precautions, such as staying indoors, avoiding traffic-heavy areas, and adhering to prescribed medications during high-pollution periods.

The findings highlight a pressing need for policy interventions to address air quality issues. Stricter enforcement of pollution norms, sustainable urban planning, and the promotion of cleaner technologies could reduce the burden on public health, particularly for those with existing conditions.

The Indian Union Health Ministry has also issued advisories urging citizens to take precautions against rising pollution levels. Vulnerable groups, including older adults and individuals with respiratory or cardiovascular diseases, are encouraged to limit outdoor activities, monitor air quality through apps, and seek medical attention for severe symptoms.

In a related development, research from Wayne State University and other institutions recently linked air pollution to higher rates of head and neck cancers. Published in Scientific Reports, the study showed a correlation between fine particulate matter (PM2.5) and cancers of the oral cavity and larynx.

“Evidence now links air pollution to an increased incidence of cancers beyond respiratory diseases. This highlights the need for immediate action to curb pollution,” Dr N.V.K. Mohan, Consultant ENT Surgeon at Calcutta Medical Research Institute (CMRI), Kolkata, stated.