Relationships of serum leptin to clinical and anthropometric findings in obese patients

Background: The authors evaluated the relationship between leptin and the clinical, anthropometric and metabolic variables connected to the metabolic syndrome in obese individuals. Methods: A large group of patients with different degrees of obesity was investigated: body mass index (BMI) values, serum leptin, fasting glucose and insulin, triglycerides and HDL-cholesterol concentrations, insulin resistance index and blood pressure were measured. Results: On multiple regression analysis, serum leptin levels appeared to be positively correlated to the BMI and to the serum HDL-cholesterol concentration. Principal component factor analysis revealed three factors, explaining 61.3% of the total variance of the sample. General features of these factors were: factor 1 - BMI values and serum leptin and fasting glucose concentration; factor 2 - systolic and diastolic blood pressure and serum triglycerides and HDL-cholesterol concentration; factor 3 - fasting serum insulin concentration and insulin resistance index. Conclusions: In obese subjects multiple factors underlie the metabolic syndrome and therefore more than one mechanism may account for the clustering characteristics. In obese patients leptin loads only one factor, and therefore leptin does not appear to be a key feature in the metabolic syndrome. On the contrary, multiple correlation and factor analysis data give rise to the hypothesis that in obese patients, leptin may play a protective role against cardiovascular risk.