Applied nutritional investigationSex differences in serum leptin and its relation to markers of cardiometabolic risk in middle-aged adults: Evidence from a population-based study

- Serum leptin concentration for women was almost threefold that of men.
- Serum leptin was indirectly related to all cardiometabolic risk factors in women.
- Men's serum leptin was directly related to high-sensitivity C-reactive protein.

ObjectiveAt elevated concentrations, circulating leptin has been associated with metabolic disturbances, namely insulin resistance, elevated blood pressure, inflammation, and endothelial dysfunction. Because women have higher leptin concentrations than men, it is possible that the effects of leptin on the metabolic profile are different between the sexes. The aim of this study was to investigate whether leptin is one of the key hormones to sex affect differences in the pathophysiology of cardiometabolic risk.MethodsParticipants were 178 men and 284 women (average age: 53.9 y), evaluated in a cross-sectional, population-based study performed in Brazil. A structural equation model was used to test a theoretic pathway for the relationship between serum leptin, obesity indicators (body weight and waist circumference), and cardiometabolic risk factors (high-sensitivity C-reactive protein; blood pressure; atherogenic dyslipidemia-total cholesterol/high-density lipoprotein cholesterol (HDL-C) ratio and triacylglycerol /HDL-C ratio; and fasting plasma glucose) stratified by sex.ResultsIn men, increasing 1 SD in serum leptin predicted an increase in 0.731 SD in body weight and in 0.123 SD in C-reactive protein. Serum leptin had positive and significant indirect effects on men's ratios of total cholesterol to HDL-C (β = 0.215) and triacylglycerol to HDL-C (β = 0.209), as well as fasting glucose (β = 0.173). In women, serum leptin predicted an increase of 0.675 SD in body weight and had positive indirect effects on all cardiometabolic risk factors evaluated.ConclusionsSerum leptin was indirectly related to cardiometabolic risk factors and its relation was modest and different between sexes. The effects of leptin through mediation of body weight and waist circumference highlight the importance of weight control to prevent cardiometabolic disorders in middle-aged adults.