Smaller Airways in Women Increase COPD Risk

Women appear to have smaller airways than men, and this structural difference may augment the risk of chronic obstructive pulmonary disease (COPD) in the female population, according to a recent study published in Radiology. 

In this study, researchers assessed ~10,000 participants between the ages of 45 and 80, enrolled in Genetic Epidemiology of COPD (COPDGene), which was a prospective multicenter observational cohort study comprised of smokers (current and former) at 21 clinical centers across the United States.

Airway disease on CT was quantified using seven metrics: airway wall thickness, wall area percent, Pi10 (square root of the wall thickness of a hypothetical airway with internal perimeter of 10 mm) for airway wall, lumen (airway passage in which air flows through) diameter, airway volume, total airway count and airway fractal dimension for airway lumen.

Airway metrics were were calculated and adjusted for age, height, race, body mass index, pack-years of smoking, current smoking status and total lung capacity, the researchers noted.

According to the results, in 420 never-smokers, CT scans showed that men had thicker airway walls than women, and airway lumen dimensions were lower in women. In analyzing 9,363 current and former smokers, the study showed that men had greater wall thickness, whereas women had narrower segmental lumen diameter. Overall, a unit change in each of the airway metrics led to a lower lung function, more dyspnea, poorer respiratory-quality of life, lower six-minute walk distance and worse survival in women compared with men, according to the findings.

“The prevalence of COPD in women is fast approaching that seen in men, and airway disease may underlie some of the high COPD numbers in women that we are seeing,” said the study’s lead author, Surya P. Bhatt, M.D., M.S.P.H., associate professor of medicine, Division of Pulmonary, Allergy and Critical Care Medicine at the University of Alabama at Birmingham via a press release. “When airways narrow due to cigarette smoking, the impact on symptoms and survival is greater in women than in men.”