title: Associations between visceral adipose tissue, inflammation and sex steroid concentrations in men.
abstract: BACKGROUND
  In men, obesity and the metabolic syndrome are accompanied by decreased testosterone levels, but little is known about the associations between visceral adipose tissue (VAT), VAT-related inflammation and sex steroids.
  
  
  OBJECTIVE
  To examine the relative impact of VAT, abdominal subcutaneous adipose tissue (SAT) and interleukin 6 (IL-6), a marker of VAT-induced inflammation, on testosterone (T) and 17β-oestradiol (E2) levels in dysmetabolic men.
  
  
  METHODS
  We study the NUMEVOX cohort of 229 men, aged 27-77 years, who all had at least one metabolic syndrome criterion (on average three). IL-6, C-reactive protein, Homeostasis Model Assessment of (HOMA) insulin resistance index (HOMA-IR), liver enzymes, E2, LH, sex hormone-binding globulin (SHBG), T, waist circumference and body mass index (BMI) were measured; bioavailable testosterone (BT) was calculated from T and SHBG; MRI-assessed VAT and SAT were analysed in 109 of these men.
  
  
  RESULTS
  Visceral adipose tissue was strongly correlated with E2 (Spearman r = 0.38, P < 0.001) and with BT/E2 ratio (r = -0.42, P < 0.001), while SAT was not correlated with either. IL-6 was correlated with E2 (r = 0.19, P = 0.007), BT (r = -0.19, P = 0.006) and BT/E2 ratio (r = -0.30 P < 0.001). In multivariate linear analysis, the relation between VAT and E2 was independent of age, BMI (P = 0.008), leptin (P < 0.001), T and SHBG. Log(IL-6) was significantly inversely related with log(BT) (P = 0.032) independently of age, VAT, leptin and HOMA-IR.
  
  
  CONCLUSIONS
  17β-oestradiol levels were positively associated with VAT, but not with SAT, while T and BT were negatively and independently associated with IL-6. The significant inverse association between IL-6 and T suggests an important role of low-grade visceral fat inflammation in the central hypogonadism associated with the metabolic syndrome.
authors.affiliation: Département d'Endocrinologie-Diabétologie-Nutrition, CHU Rennes, Université Rennes1, Hôpital Sud, Rennes, France. al_gautier@hotmail.com
authors.forename: Alain
authors.initials: A
authors.lastname: Gautier
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bonnet
authors.forename: Séverine
authors.initials: S
authors.lastname: Dubois
authors.forename: Catherine
authors.initials: C
authors.lastname: Massart
authors.forename: Catherine
authors.initials: C
authors.lastname: Grosheny
authors.forename: Anne
authors.initials: A
authors.lastname: Bachelot
authors.forename: Christophe
authors.initials: C
authors.lastname: Aubé
authors.forename: Beverley
authors.initials: B
authors.lastname: Balkau
authors.forename: Pierre-Henri
authors.initials: PH
authors.lastname: Ducluzeau
mesh_terms: D000328:Adult; D000368:Aged; D004958:Estradiol / Q000097:blood; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism*; D015850:Interleukin-6 / Q000097:blood; D050152:Intra-Abdominal Fat / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013256:Steroids / Q000097:blood*; D013739:Testosterone / Q000097:blood
chemical_list: D015850:Interleukin-6; D013256:Steroids; D013739:Testosterone; D004958:Estradiol