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Chronic obstructive pulmonary disease, or COPD, is the fourth leading cause of death worldwide, responsible for 3.5 million deaths in 2021, according to the World Health Organization.

It's a common disease in the United States, affecting about 6% of U.S. adults and ranking among the country's top 10 causes of death, the U.S. Centers for Disease Control and Prevention reports. Advertisement

As people age, the frequency of these cases increases significantly, with some estimates indicating that COPD may affect 20% to 25% of people over age 70 .

Now, researchers are trying to learn how many people have "young COPD," meaning the condition is diagnosed before 50 years of age. "Young COPD" was present in 4.5% of adults under 50 in the population studied, a new study published

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