Images show airway metrics.(A)非增强轴位胸部CT图像显示气管节段横切面。(B)插图显示分段气道壁(绿色)和气道腔(粉色)。(C)分段气道树与颜色编码的分支。The resulting total airway count (TAC) and airway fractal dimension (AFD) are shown inC. Image courtesy of RSNA
August 3, 2022 — Structural differences in lung airways between men and women may be the cause of differences inchronic obstructive pulmonary disease(COPD) prevalence and outcomes between the sexes. According to a large, multicenter study published in the journalRadiology, researchers found that even among adults who have never smoked, or who have smoked less than 100 cigarettes in their lifetime, lung airways were smaller in women, which can lead to a higher risk for lung disease.
COPD refers to a group of diseases, such as emphysema and chronic bronchitis, that cause airflow blockage and breathing-related problems. More than 15 million Americans haveCOPD, according to theCenters for Disease Control and Prevention.
Overall, men have a higher rate of diagnosis and mortality, but with changes in smoking behavior and increasing urbanization, the prevalence of COPD in women is on the rise.
“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 theUniversity of Alabama at Birmingham. “When airways narrow due to cigarette smoking, the impact on symptoms and survival is greater in women than in men.”
The assumption that women have smaller airways is based on comparisons of the trachea and main stem bronchi, but few studies have compared distal airways in normal individuals or accounted for differences in lung size.
For this study, researchers analyzed data from nearly 10,000 participants enrolled inGenetic 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 onCTwas 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.
“The growth of airways and lungs in early life is generally more proportionate in women than in men,” Dr. Bhatt said.
In 420 never-smokers,CT scansrevealed 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.
在9363名吸烟者和戒烟者中，男性的管壁厚度更大，而女性的管壁直径更窄。与男性相比，每个气道指标的单位变化(壁高或管腔低)会导致肺功能降低，呼吸困难(呼吸短促)增加，呼吸质量下降，步行距离减少6分钟，生存率降低。
“The differences in airway dimensions even after adjusting for height and lung size, and the greater impact of changes in airway size on clinical outcomes in women, was remarkable in that women appear to have a lower reserve against developing airway disease and COPD,” Bhatt noted.
Bhatt noted that the research implicates that sex differences should be factored into the development of new therapies for airway disease.
For more information:www.rsna.org
August 01, 2022
