Leptin concentrations do not correlate with fat mass nor with metabolic risk factors in morbidly obese females.
OBJECTIVE
To investigate the determinants of leptinemia in a cohort of morbid obese females compared to those of normal weight and mild-to-moderate obesity, and the relationships between leptin and metabolic derangements associated with obesity.


METHODS
Recruited females were: moderately obese [n=44; body mass index (BMI) 25-40 kg/m2], morbidly obese (n=34; BMI > or = 40 kg/m2) and normal weight volunteers (n=12; BMI 19-25 kg/m2). Fat mass assessed by bioelectrical impedance and fat distribution by waist-to-hip ratio (WHR) were determined in all subjects. Biochemical determinations included plasma leptin, lipoprotein profile, fasting insulin and cortisol.


RESULTS
Plasma leptin values were significantly increased in morbid obese patients (54.95 +/- 1.8 ng/ml) compared to those moderately obese (30.2 +/- 1.7 ng/ml; p<0.001) and to controls (9.77 +/- 1.4 ng/ml; p<0.001). Fat and age-adjusted leptin values were not different between groups. When subjects with a BMI <40 kg/m2 were considered, plasma leptin was significantly and positively related to anthropometric variables (BMI, percentage body fat and WHR), total cholesterol, LDL-cholesterol, plasma triglycerides, AST, ALT and uric acid; and negatively with HDL-cholesterol. In contrast, when morbidly obese patients were analyzed separately, no relationships were observed between leptin concentrations and BMI, percentage of adiposity or biochemical variables. For obese patients no significant differences were observed in the adjusted leptin values with respect to the presence of diabetes, dyslipidemia or hypertension.


CONCLUSIONS
In morbidly obese women, the plasma leptin concentrations, although increased, do not reflect the amount of adipose stores, and as such, factors other than simply adiposity need to be invoked to explain the variation in leptin values.
García-Lorda
P
P
Unitat de Nutrició Humana, Hospital Universitari Sant Joan de Reus, Facultat de Medicina i Ciencies de la Salut, Universitat Rovira i Virgili, Reus, Spain.
Bulló
M
M
Vilà
R
R
del Mar Grasa
M
M
Alemany
M
M
Salas-Salvadó
J
J
D000273:Adipose Tissue; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D017097:Electric Impedance; D005215:Fasting; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood*; D008074:Lipoproteins / Q000097:blood; D009767:Obesity, Morbid / Q000378:metabolism*; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D014527:Uric Acid / Q000097:blood
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D007328:Insulin; D020738:Leptin; D008074:Lipoproteins; D014280:Triglycerides; D014527:Uric Acid; D002784:Cholesterol; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D006854:Hydrocortisone