Title : BMI-specific associations between atherogenic index of plasma and atherosclerotic cardiovascular disease in young adults: A nationwide cohort study
Abstract:
Background: The atherogenic index of plasma (AIP), derived from the triglycerides/high-density lipoprotein cholesterol ratio, reflects the balance between atherogenic and protective lipoproteins. Although it has been associated with cardiovascular risk factors, such as obesity, and with atherosclerotic cardiovascular disease (ASCVD), the prognostic value in young adults—particularly across the body mass index (BMI) spectrum—remains poorly defined.
Methods: We analyzed 6,090,721 Korean adults aged 20–39 years from the National Health Insurance Service who underwent standardized national health screening between 2009 and 2012. AIP was log-transformed and categorized into quartiles (Q). The primary endpoint was ASCVD, defined as a composite of cardiovascular death, myocardial infarction, ischemic stroke, peripheral artery disease. Participants were followed until the occurrence of clinical event or December 31, 2023, whichever came first, after 1-year lag. Cox proportional hazards models estimated hazard ratios (HRs) for ASCVD according to AIP quartiles, overall and stratified by BMI.
Results: During a median follow-up of 13.6 years, 73,526 ASCVD events occurred (1.21%) in our cohort (mean age, 30.8 years; men, 59.5%; mean LDL-c levels, 104.6 mg/dL). Higher AIP showed a graded association with ASCVD risk after multivariable adjustment, including LDL-c levels (adjusted HR vs. Q1: 1.05 for Q2, 1.13 for Q3, 1.33 for Q4). This relationship persisted across all BMI categories, including underweight (BMI<18.5 kg/m2; HR 1.47) and normal weight (18.5–22.9 kg/m²; HR 1.34), with risks comparable to obesity (≥25 kg/m2, HR 1.50). Penalized spline analyses demonstrated significant non-linear associations in all BMI strata (p <0.01), with the earliest and steepest risk increase in underweight individuals. Subgroup analyses also indicated a consistent association across clinically relevant subgroups.
Conclusions: In this largest young adult cohort to date, AIP was an independent predictor of ASCVD across the BMI spectrum, even among individuals traditionally considered low risk. These findings highlight AIP as a simple, accessible biomarker that may refine early risk assessment and support tailored prevention strategies beyond LDL-c–based approaches.
