This study aims to investigate the association between weight status and the atherogenic index of plasma(AIP) among adolescents in Liangshan Prefecture, with the goal of providing evidence for the prevention of atherosclerosis in this population.

In October 2021, a sample of middle school students from three schools in Liangshan Prefecture was selected. Follow-up survey was conducted in March 2023. General demographic characteristics were collected via structured questionnaires. Anthropometric measurements, including height, weight, and waist circumference(WC), were obtained. Fasting blood samples were collected to measure serum triglycerides(TG) and high-density lipoprotein cholesterol (HDL-C). The associations between baseline body mass index(BMI) and WC with follow-up atherogenic index of plasma (AIP) were assessed using a linear regression model incorporating restricted cubic splines (RCS). A mediation analysis model was employed to evaluate the potential mediating role of baseline AIP in the relationship between baseline BMI (or WC) and follow-up AIP.Furthermore, the association between baseline weight and WC categories and changes in AIP from baseline to follow-up was examined using logistic regression.

The median baseline age of the 1 023 participants was 14.0 years, with 43.7% being male. The RCS curve indicated that baseline BMI was linearly associated with follow-up AIP (P_general<0.001, P_nonlinearity=0.108). In contrast, baseline WC exhibited a nonlinear association with follow-up AIP (P_general<0.001, P_nonlinearity=0.002). Mediation analysis revealed that baseline AIP fully mediated the association between baseline BMI (or WC) and follow-up AIP (BMI: P_direct=0.06,P_indirect<0.001; WC: P_direct=0.13, P_indirect<0.001). Compared with adolescents with normal BMI, those who were overweight or obese at baseline had significantly higher odds of persistent elevated AIP levels (OR=3.570, P<0.001). Similar findings were observed when WC was used as the indicator of weight status (OR=3.388, P<0.001).

Both elevated BMI and increased WC in adolescents are associated with an increased short-term risk of high AIP. Preventive strategies targeting middle school students should be implemented to mitigate the early onset of atherosclerosis.