Air Pollution Raises Risk of Cardiovascular Disease

High exposure to fine particulate matter found to increase biomarkers for inflammation and oxidative stress.

Air pollution has been known to cause numerous lung-related and other health issues, while also damaging the environment. For these reasons, the United States and other countries have tried to implement measures that limit air pollution.

Findings from a new study published by Circulation suggest that exposure to high levels of air pollution may also result in increased stress hormone levels and negative metabolic changes in healthy young adults living in China.

However, the authors found that air purifiers lessen the effects of air pollution in this population.

The authors focused on fine particulate matter (PM2.5), which is emitted from vehicles, factories, fires, smoke, and power plants. Many previous studies have suggested PM2.5 may result in cardiovascular and metabolic conditions, but the underlying mechanisms are unclear, according to the authors.

In the study, investigators used metabolomics to determine the chemical processes used by cells to create the life-sustaining substances and energy. This method can show how glucose, amino acids, fatty acids, and lipids are metabolized by the body.

Included in the study were 55 healthy college students who were randomized to receive real or fake air purification systems in their dormitory rooms. Both indoor and outdoor PM2.5 were measured during the study period. The authors also conducted health tests and analyzed blood serum and urine samples for biomarkers of metabolites, inflammation, and oxidative stress.

Specifically, the authors looked for differences in blood serum metabolites, biomarkers, and blood pressure when exposure to PM2.5 increased, according to the study.

The investigators discovered significant changes in 97 blood serum metabolites after exposure to air pollution.

Notably, the real air purifiers reduced indoor air pollution by 82% compared with the fake purifiers, according to the study. This suggests that the filters could be an approach to reduce indoor air pollution.

In the short-term, the air purifiers were also observed to reduce stress hormone levels. Additionally, when used for 24 hours, the purifiers reduced levels of PM2.5 to safe levels per the World Health Organization, according to the study.

Higher exposure to PM2.5 was observed to increase stress hormone levels, which is thought to result in high blood pressure and have inflammatory and metabolic effects.

Exposure to fine particulate matter was also observed to change the metabolism of glucose, amino acids, fatty acids, and lipids, according to the study.

The observed changes—high blood pressure, insulin resistance, and biomarkers of inflammation and oxidative stress—among those expose to high levels of PM2.5 likely play a role in negative cardiovascular effects brought on by air pollution exposure, according to the authors.

“Levels of stress hormones, systolic blood pressure and biomarkers of oxidative stress and inflammation were significantly lower when using real air purifiers,” said study author Haidong Kan, MD, PhD. “Although we found significant health benefits with air purifiers, the actual health protection people could get from air purifiers in real living conditions is still not well-determined.”

Since air pollution levels are higher in China compared with the United States or Europe, it is unknown if these results will translate; however, the authors note that their new findings show air pollution’s potential health impact.

“Future studies should examine whether the health benefits from short-term air purification can improve long-term health, and whether these findings are also found in people who live in low pollution areas,” Dr Kan said.