Increased COPD risk for women due to smaller airways

Structural differences in lung airways between men and woman may be the cause of differences in chronic obstructive pulmonary disease (COPD) prevalence and outcomes between the sexes.

For this study, researchers analyzed data from nearly 10,000 participants enrolled in Genetic Epidemiology of COPD (COPDGene), a prospective multicenter observational cohort study of current and former smokers, as well as never smokers, between the ages of 45 and 80 years, at 21 clinical centers across the United States. The researchers looked at data of never, current and former smokers enrolled in COPDGene from January 2008 to June 2011 and followed up longitudinally until November 2020.

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.

Each airway metric was calculated and adjusted for age, height, race, body mass index, pack-years of smoking, current smoking status and total lung capacity.

In 420 never-smokers, CT scans revealed that men had thicker airway walls than women, whereas, after accounting for height and total lung capacity, airway lumen dimensions were lower in women than in men.

In 9,363 current and former smokers, men had greater wall thickness, whereas women had narrower segmental lumen diameter. A unit change in each of the airway metrics (higher wall or lower lumen measure) resulted in lower lung function, more dyspnea (shortness of breath), poorer respiratory-quality of life, lower six-minute walk distance and worse survival in women compared with men.

The researchers noted that the research implicates that sex differences should be factored into the development of new therapies for airway disease.

Ref: Surya P. Bhatt et. al, Sex Differences in Airways at Chest CT: Results from the COPDGene Cohort, JOURNAL Radiology,2-Aug-2022