Air pollution linked to increased hospitalizations for major heart and lung diseases

Short-term and long-term exposure to fine particulate matter (PM)_2.5) Air pollution is associated with an increased risk of hospitalization for major heart and lung conditions, two large studies published in the United States have found. BMJ today.

Taken together, these results suggest that there is no safe threshold for heart and lung health.

According to the Global Burden of Disease Study, exposure to PM_2.5 This accounts for an estimated 7.6% of global total mortality and 4.2% of global disability-adjusted life years (a measure of years lived in good health).

In light of this extensive evidence, the World Health Organization (WHO) updated its air quality guidelines in 2021, increasing the annual average PM_2.5 Levels must not exceed 5 μg/m³ and 24-hour average PM_2.5 Levels must not exceed 15 μg/m³ Over 3-4 days each year.

In the first study, researchers correlated average daily PM._2.5 From 2000 to 2016, we surveyed the residential ZIP codes of nearly 60 million U.S. adults aged 65 and older (84% white, 55% female). They then used Medicare insurance data to track hospitalizations over an average of eight years.

Average PM after accounting for various economic, health, and social factors_2.5 Three years of exposure was associated with an increased risk of first hospitalization for seven major cardiovascular diseases: ischemic heart disease, cerebrovascular disease, heart failure, cardiomyopathy, arrhythmia, valvular heart disease, thoracic aortic aneurysm, and abdominal aortic aneurysm. Was.

Comparison with exposure dose of 5μg/m³ Below (WHO air quality guidelines for annual PM)_2.5), 9-10 μg/m exposure.³which covers the US national average of 9.7 μg/m3.³ It was associated with a 29% increased risk of hospitalization for cardiovascular disease during the study period.

On an absolute scale, the risk of hospitalization for cardiovascular disease increased from 2.59% at 5 μg/m exposure.³ 3.35% or less for exposures between 9 and 10 μg/m³. “So if you manage to reduce your annual PM;_2.5 Less than 5μg/m³could potentially avoid 23% of cardiovascular hospitalizations,” the researchers said.

These cardiovascular effects persisted for at least 3 years after PM exposure._2.5and susceptibility varies by age, education, access to health services, and local poverty level.

The researchers say their findings suggest that there is no safe threshold for the chronic effects of PM._2.5 It appears that adherence to WHO air quality guidelines could have significant benefits, with implications for overall cardiovascular health.

“On February 7, 2024, the U.S. Environmental Protection Agency (EPA) updated its annual National Air Quality Standards for PM._2.5 Set stricter limits of 9 µg/m or less³. This is his first update since 2012. However, it is still significantly higher than 5 µg/m.³ Established by WHO. “Clearly, the newly published national standards were not sufficient to protect public health,” they added.

In the second study, researchers used county-level daily PM._2.5 Concentration and medical claims data to track hospitalizations and emergency department visits for natural causes, cardiovascular disease, and respiratory disease for 50 million U.S. adults ages 18 and older from 2010 to 2016.

Over 10 million hospitalizations and 24 million emergency department visits were recorded during the study period.

They believe that short-term exposure to PM_2.5is statistically associated with increased hospitalization rates for natural causes, cardiovascular disease, and respiratory disease, and increased rates of emergency department visits for respiratory disease, even at concentrations below the limits in the WHO’s new air quality guidelines. significantly related.

For example, on days when it’s 1 p.m. every day,_2.5 Levels were below the WHO’s new air quality guideline limit of 15μg/m3.³an increase of 10 μg/m³ in the afternoon_2.5 It was associated with 1.87 additional hospitalizations per day per million adults aged 18 and over.

The researchers say their findings make an important contribution to the debate about revising air quality limits, guidelines and standards.

Both research teams acknowledged some limitations, including possible misclassification of exposure, and noted that other unmeasured factors may have influenced the results. Additionally, the findings may not apply to individuals without health insurance, children and adolescents, or those living outside the United States.

But taken together, these new results provide a valuable reference for future national air pollution standards.