title: Sex hormone-binding globulin, but not testosterone, is associated prospectively and independently with incident metabolic syndrome in men: the framingham heart study.
abstract: OBJECTIVE
  The association between total testosterone and metabolic syndrome has prompted speculation that low testosterone contributes to the pathophysiology of metabolic syndrome in men. We determined whether testosterone or sex hormone-binding globulin (SHBG) is independently associated with the risk of metabolic syndrome.
  
  
  METHODS
  Cross-sectional relationships of hormone levels with metabolic syndrome were assessed in a sample of men in generation 2 of the Framingham Heart Study (FHS) who did not receive testosterone or androgen-deprivation therapy (n = 1,625) and confirmed in a validation sample of men in FHS generation 3 (n = 1,912). Hormone levels in generation 2 examination 7 were related prospectively to incident metabolic syndrome 6.6 years later at examination 8. Testosterone was measured using liquid chromatography-tandem mass spectrometry, SHBG was measured by immunofluorometric assay, and free testosterone was calculated. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. RESULTS Cross-sectionally, testosterone and SHBG were more strongly associated with metabolic syndrome than free testosterone in the training sample. SHBG, but not testosterone or free testosterone, was significantly associated with metabolic syndrome after adjusting for age, smoking, BMI, and insulin sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR]). These findings were confirmed in a validation sample. Longitudinally, SHBG at examination 7, but not testosterone or free testosterone, was associated with incident metabolic syndrome at examination 8 after adjusting for age, smoking, BMI, and HOMA-IR. Multivariable analyses suggested that age, BMI, and insulin sensitivity independently affect SHBG and testosterone levels and the risk of metabolic syndrome and its components.
  
  
  CONCLUSIONS
  SHBG, but not testosterone, is independently associated with the risk of metabolic syndrome. These data do not reveal an independent prospective relationship between testosterone and metabolic syndrome in men.
authors.affiliation: Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA, USA. bhasin@bu.edu
authors.forename: Shalender
authors.initials: S
authors.lastname: Bhasin
authors.forename: Guneet K
authors.initials: GK
authors.lastname: Jasjua
authors.forename: Michael
authors.initials: M
authors.lastname: Pencina
authors.forename: Ralph
authors.initials: R
authors.lastname: D'Agostino
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Coviello
authors.forename: Ramachandran S
authors.initials: RS
authors.lastname: Vasan
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Travison
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002853:Chromatography, Liquid; D003430:Cross-Sectional Studies; D015200:Fluoroimmunoassay; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D024821:Metabolic Syndrome / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D053719:Tandem Mass Spectrometry; D013739:Testosterone / Q000097:blood*
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone