Diabetes, Metabolic Syndrome and Obesity (Dec 2021)
Leptin Concentrations in Non-Obese and Obese Non-Diabetes Nigerian-Africans
Abstract
Obiageli Uzoamaka Agbogu-Ike,1 Dimie Ogoina,2 Geoffrey Chukwubuike Onyemelukwe1 1Department of Medicine, Ahmadu Bello University (ABU) Teaching Hospital, Zaria, Nigeria; 2Department of Medicine, Niger Delta University Teaching Hospital, Okolobiri, Bayelsa, NigeriaCorrespondence: Obiageli Uzoamaka Agbogu-IkeDepartment of Medicine, ABUTH, Zaria, NigeriaTel +234 8129930000Email [email protected]: Controversial findings exist on the role of leptin in obesity and its correlation with metabolic variables, with few data emanating from Nigerian-Africans. Plasma leptin was therefore determined in obese and non-obese. Its relationship with obesity indices and metabolic variables were further envisaged.Materials and Methods: A cross-sectional comparative study on 87 randomly-selected non-diabetes Nigerians distributed into 3 groups (24 normal, 23 pre-obese and 40 obese). Obesity indices, fasting Insulin (FI) and homeostasis model assessment-insulin resistance (HOMA-IR) were determined. Plasma leptin was determined by sandwich enzyme-linked immunosorbent assay. Mann-Whitney U-test, Independent Kruskal-Wallis test, Spearman correlation and Step-wise Multivariate Logistic Regression analysis determined outcomes.Results: Median+IQR leptin concentrations were higher in obese {61.8(40.8, 91.4) ng/mL, p< 0.001} than pre-obese {42.7(28.0, 51.7) ng/mL, p=0.003} and normal {28.6(20.7, 39.8) ng/mL, p=0.03} BMI categories. Leptin was higher (p< 0.001) in females than males {Median+IQR, 52.0 (35.0, 80.0) ng/mL versus 34.0(24, 65.0 ng/mL)}. Leptin was positively correlated with body fat percentage (BFP), r=0.57; waist circumference (WC), r=0.46 and body mass index (BMI), r=0.50, p< 0.001, respectively in all subjects, with higher correlation coefficient in males than females. Leptin showed sex-specific correlations to age, FI and HOMA-IR. In the unadjusted models, central obesity/generalized obesity, WC, BMI, BFP, combined pre-obesity/obesity, younger age and female sex were significantly (p< 0.001) associated with log-transformed leptin. WC (OR: 1.2, 95% CI, 1.05– 1.38, p=0.009), BFP (OR: 1.41, 95% CI, 1.07– 1.84, p=0.013) and BMI (OR: 1.6, 95% CI, 1.13– 2.31, p=0.008) in men and all subjects, were independently associated with hyperleptinaemia following adjustments.Conclusion: Plasma leptin concentrations, fasting insulin and insulin resistance are higher in obese and pre-obese than normal controls, with females showing higher leptin concentrations than males. Leptin is independently related to BMI, BFP, WC, female sex and generalized/central obesity in Nigerian-Africans especially males. It showed sex-specific relations to age, fasting insulin and HOMA-IR.Keywords: plasma leptin, obese, pre-obese, normal healthy non-diabetics, body fat percentage, HOMA-insulin resistance, Nigerian-Africans
