Association Between Serum Atherogenic Index and Cardiovascular Disease in Early Adulthood

BACKGROUND: The atherogenic index of plasma (AIP), calculated as log(triglycerides/high-density lipoprotein cholesterol), is a novel marker of atherogenic risk, but its association with cardiovascular disease (CVD) and mortality in early adulthood remains unclear. OBJECTIVES: This study aimed to investigate whether AIP independently predicts the risk of CVD (including stroke) and all-cause mortality in young adults. METHODS: We analyzed 64,416 participants aged 18-44 years without prior CVD from the Kailuan Study (2006-2016). AIP was calculated at baseline, and participants were categorized into quartiles. The primary outcomes were incident CVD, stroke, and all-cause mortality, ascertained through December 2023. Multivariable Cox models adjusted for traditional risk factors, lipids, renal function, and medication use were used to estimate HRs. RESULTS: Over a mean follow-up of 14.65 years (Q1-Q3: 10.60-16.90 years), 1,853 CVD events, 1,571 stroke events, and 1,332 cases of all-cause mortality occurred. After full adjustment, compared with the lowest AIP quartile (Q1), the HRs for CVD in Q2-Q4 were 1.16 (95% CI: 0.99-1.36), 1.29 (95% CI: 1.11-1.50), and 1.36 (95% CI: 1.17-1.59), respectively. Corresponding HRs for stroke were 1.14 (95% CI: 0.97-1.35), 1.21 (95% CI: 1.03-1.43), and 1.26 (95% CI: 1.07-1.49). No significant association was found between AIP and all-cause mortality after multivariable adjustment. Sensitivity and competing risk analyses supported the robustness of these findings. CONCLUSIONS: Higher AIP is independently associated with increased risks of CVD and stroke in young adults. AIP may serve as a useful biomarker for early cardiovascular risk stratification in this population.