Leptin Concentrations in Non-Obese and Obese Non-Diabetes Nigerian-Africans

Abstract

Background 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.

Estimation of Leptin and Estrogen Hormones in Obese Women with Arthritis

“…Our study revealed that there was no difference in concentration of leptin between obese, obese RA and nonobese women. This result disagrees with previous study concluded that leptin hormone showed highly significant differences among obese and non-obese women (28) .…”