High Attenuation Areas on Chest CT in Community-Dwelling Adults: The MESA Study

Abstract

Evidence suggests that lung injury, inflammation and extracellular matrix remodeling precede lung fibrosis in interstitial lung disease (ILD). We examined whether a quantitative measure of increased lung attenuation on computed tomography (CT) detects lung injury, inflammation and extracellular matrix remodeling in community-dwelling adults sampled without regard to respiratory symptoms or smoking.

We measured high attenuation areas (HAA; percentage of lung voxels between -600 and -250 Hounsfield Units) on cardiac CT scans of adults enrolled in the Multi-Ethnic Study of Atherosclerosis.

HAA was associated with higher serum matrix metalloproteinase-7 (mean adjusted difference 6.3% per HAA doubling, 95% CI 1.3 to 11.5), higher interleukin-6 (mean adjusted difference 8.8%, 95% CI 4.8 to 13.0), lower forced vital capacity (mean adjusted difference -82 mL, 95% CI -119 to -44), lower 6-minute walk distance (mean adjusted difference -40 m, 95% CI -1 to -80), higher odds of interstitial lung abnormalities at 9.5 years (adjusted OR 1.95, 95% CI 1.43 to 2.65), and higher all cause-mortality rate over 12.2 years (HR 1.58, 95% CI 1.39 to 1.79).

High attenuation areas are associated with biomarkers of inflammation and extracellular matrix remodeling, reduced lung function, interstitial lung abnormalities, and a higher risk of death among community-dwelling adults.