Incidence of interstitial lung abnormalities: the MESA Lung Study.

Overview

abstract

BACKGROUND: The incidence of newly developed interstitial lung abnormalities (ILA) and fibrotic ILA has not been previously reported. METHODS: Trained thoracic radiologists evaluated 13 944 cardiac computed tomography scans for the presence of ILA in 6197 Multi-Ethnic Study of Atherosclerosis (MESA) longitudinal cohort study participants >45 years of age from 2000 to 2012. Five percent of the scans were re-read by the same or a different observer in a blinded fashion. After exclusion of participants with ILA at baseline, incidence rates and incidence rate ratios for ILA and fibrotic ILA were calculated. RESULTS: The intra-reader agreement of ILA was 92.0% (Gwet's AC1 0.912, intraclass correlation coefficient (ICC) 0.982) and the inter-reader agreement of ILA was 83.5% (Gwet's AC1 0.814, ICC 0.969). Incidence of ILA and fibrotic ILA was estimated to be 13.1 and 3.5 cases per 1000 person-years, respectively. In multivariable analyses, age (hazard ratio (HR) 1.06 (95% CI 1.05-1.08); p<0.001 and HR 1.08 (95% CI 1.06-1.11); p<0.001), high attenuation area at baseline (HR 1.05 (95% CI 1.03-1.07); p<0.001 and HR 1.06 (95% CI 1.02-1.10); p=0.002) and the MUC5B promoter single nucleotide polymorphism (HR 1.73 (95% CI 1.17-2.56); p=0.01 and HR 4.96 (95% CI 2.68-9.15); p<0.001) were associated with incident ILA and fibrotic ILA, respectively. Ever-smoking (HR 2.31 (95% CI 1.34-3.96); p=0.002) and an idiopathic pulmonary fibrosis polygenic risk score (HR 2.09 (95% CI 1.61-2.71); p<0.001) were associated only with incident fibrotic ILA. CONCLUSIONS: Incident ILA and fibrotic ILA were estimated by review of cardiac imaging studies. These findings may lead to wider application of a screening tool for atherosclerosis to identify pre-clinical lung disease.