Abstract

Background: Leptin, an adipocyte-derived hormone, plays an important role in the regulation of body weight and energy homeostasis. Dysregulation of leptin has been associated with obesity, metabolic syndrome, and insulin resistance. Objective: To determine serum leptin levels and investigate their associations with age, sex, body mass index (BMI), metabolic syndrome, and insulin resistance. Subjects and Methods: A cross-sectional study was conducted on 163 individuals aged 18 years and older who underwent health check-ups at Hue Central Hospital between October 2025 and February 2026. Multivariate linear regression analysis was performed to evaluate the associations between serum leptin levels and the study variables. Results: The median leptin level was 1.95 (1.00 - 5.35). Females had higher leptin levels than males, 2.91 (1.54 - 9.93) vs. 1.15 (0.39 - 1.92), respectively (p < 0.001). Leptin levels tended to increase with BMI: 0.66 (0.18 - 1.45) in the underweight group, 1.48 (0.66 - 2.85) in the normal group, and 3.64 (1.63 - 9.85) in the overweight/obese group. Sex, BMI, and insulin resistance were independently associated with leptin levels. Conclusion: Leptin levels in individuals undergoing health check-ups at Hue Central Hospital were relatively low. Sex, BMI, and insulin resistance were independent factors associated with leptin levels.