Interstitial Lung Abnormality in Health Screening Examinees: Prevalence, Outcomes, and Risk Factors.

Abstract

Background: The prevalence, outcome and risk factors of interstitial lung abnormality (ILA) in the Asian population remains unclear.

Methods: We retrospectively enrolled participants who had health check-up and undergone serial chest computed tomography (CT) more than 5 years apart from baseline. The presence of ILA, as well as the temporal changes, was evaluated. Multivariable logistic regression was used to assess baseline risk factors associated with the progressive ILA (defined as development or progression of equivocal ILA or ILA) upon follow-up.

Results: In total, 2,589 participants with a mean baseline age of 49 years (57 years upon follow-up scans) and a median follow-up of 7.0 years were included. We found that the prevalence of ILA or equivocal ILA increased between baseline and follow-up (baseline: 0.2% and 0.3%, respectively; follow-up: 0.8% and 0.9%, respectively) (P < 0.001). Additionally, radiologic progression was observed in 83.3% of participants with ILA at baseline. In the multivariable analysis, older age, ever-smoking status, higher white blood cell counts, higher erythrocyte sedimentation rates, and higher rheumatoid factors at baseline were independent risk factors for progressive ILA upon follow-up. Both ILA and equivocal ILA at the follow-up CT were significantly associated with all-cause mortality (adjusted hazard ratio [aHR] for equivocal ILA, 3.73, P = 0.005; aHR for ILA, 4.01, P = 0.004) when compared with those without ILA; however, progressive ILA further increased the risk of mortality (aHR, 3.92, P < 0.001) compared with non-progressive or no ILA.

Conclusion: The prevalence of ILA in middle-aged Korean health screening participants was relatively low but increased with age, with its presence associated with long-term impacts on mortality. Radiologic progression on ILA at baseline was common. Risk factors for progressive ILA, such as age, smoking history, and elevated inflammatory markers, were identified. These findings emphasize the importance of early identification and monitoring of ILA in at-risk populations to improve long-term outcomes.