title: Sex differences in serum leptin and its relation to markers of cardiometabolic risk in middle-aged adults: evidence from a population-based study.
abstract: OBJECTIVE
  At 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.
  
  
  METHODS
  Participants 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.
  
  
  RESULTS
  In 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.
  
  
  CONCLUSIONS
  Serum 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.
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, São Paulo, Brazil. Electronic address: michelle.castro@usp.br.
authors.forename: Michelle Alessandra
authors.initials: MA
authors.lastname: de Castro
authors.affiliation: Department of Epidemiology and Biostatistics, Fluminense Federal University, Niteroi, RJ, Brazil.
authors.forename: Valéria Troncoso
authors.initials: VT
authors.lastname: Baltar
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, São Paulo, Brazil.
authors.forename: Dirce Maria Lobo
authors.initials: DM
authors.lastname: Marchioni
authors.affiliation: Department of Nutrition, School of Public Health, University of São Paulo, São Paulo, Brazil.
authors.forename: Regina Mara
authors.initials: RM
authors.lastname: Fisberg
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D001835:Body Weight; D001938:Brazil; D002097:C-Reactive Protein / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000097:blood* / Q000209:etiology; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D008076:Cholesterol, HDL; D020738:Leptin; D008055:Lipids; D014280:Triglycerides; D002097:C-Reactive Protein; D002784:Cholesterol
keywords: Adults; Cardiometabolic risk factors; Cross-sectional study; Leptin; Obesity; Structural equation model