Introduction:
This study aimed to determine the prevalence of dyslipidemia and to assess the predictive performance of lipid ratios, specifically the Atherogenic Index of Plasma (AIP) and the total cholesterol (TC) to high-density lipoprotein cholesterol (HDL-C) (TC/HDL) ratio, compared to body mass index (BMI) in identifying dyslipidemia among non-obese male university students.

Material and methods:
A cross-sectional study was conducted among 150 male students aged 20–30 years at a Saudi Arabian university. Participants underwent fasting lipid profiling, anthropometric measurements, and assessments of lifestyle behaviors including diet, physical activity, and smoking. Dyslipidemia was defined based on the NCEP-ATP III criteria. Predictive accuracy of AIP, TC/HDL ratio, and BMI was evaluated using receiver operating characteristic (ROC) curve analysis and logistic regression.

Results:
Dyslipidemia was detected in 60.7% of participants, despite a mean BMI of 25.3 ±4.0 kg/m², indicating that a substantial proportion of metabolically at-risk individuals were not obese. Unhealthy lifestyle behaviors were associated with an approximately eightfold increase in the odds of dyslipidemia (p < 0.001). Both AIP (AUC = 0.865) and TC/HDL ratio (AUC = 0.873) demonstrated significantly superior predictive performance compared with BMI (AUC = 0.570). More than 63% of students were classified as high-risk based on AIP levels. Cluster analysis revealed a distinct LDL–TG dominant phenotype strongly associated with unhealthy lifestyle factors.

Conclusions:
Lipid ratios, particularly AIP and TC/HDL, outperformed BMI in predicting early dyslipidemia among non-obese young adults. Incorporating these indices into routine screening could facilitate earlier detection of cardiovascular risk in university and preventive health settings, emphasizing the importance of targeted lifestyle interventions.