Associations between High-Density Lipoprotein Cholesterol and Interstitial Lung Abnormalities in the Korean National Lung Cancer Screening

Background High-density lipoprotein (HDL) cholesterol exerts anti-inflammatory, antioxidative, and endothelial-protective effects, yet its role in interstitial lung abnormalities (ILA) remains unclear. Methods We analyzed baseline screening from heavy smokers who participated in the Korean national lung cancer screening program (2019–2021). HDL cholesterol was measured at two prescreening time points (remote and immediate) and categorized as normal or low. Participants were also classified into four HDL trajectories: normal-to-normal, low-to-normal, normal-to-low, and low-to-low. We used logistic regression to estimate odds ratios (ORs) for ILA, adjusting for demographic characteristics, body mass index, lifestyle factors, comorbidities, income status, lipid profiles, and statin use. Results Among 159 729 participants (mean age, 61.7 years; 98.2% men), ILA was detected in 2.9%, with higher prevalence in those with low HDL at immediate prescreening compared with normal HDL (3.5% versus 2.7%). Participants with low HDL cholesterol had a higher proportion of obesity (6.1% versus 3.5%) and more frequent statin use (40.0% versus 34.4%) than those with normal HDL cholesterol. Compared with the normal-to-normal group (2.6%), ILA prevalence increased across the low-to-normal (3.1%), normal-to-low (3.5%), and low-to-low (3.6%) groups. Low HDL at immediate prescreening was associated with a 28% higher risk of ILA (95% CI, 1.19–1.38; p<0.001). Compared with normal-to-normal HDL, the odds of ILA were higher in low-to-normal (adjusted OR, 1.17; 95% CI, 1.06–1.29; p=0.002), normal-to-low (adjusted OR, 1.30; 95% CI, 1.18–1.44; p<0.001), and low-to-low groups (adjusted OR, 1.32; 95% CI, 1.20–1.45; p<0.001). Conclusions Low HDL cholesterol was associated with a higher risk of ILA.