title: Determinants of testosterone recovery after bariatric surgery: is it only a matter of reduction of body mass index?
abstract: OBJECTIVE
  To explore the correlation models between body mass index (BMI) and sex hormones constructed from a male cross-sectional survey and evaluate the effects of surgery-induced weight loss on sex hormones in morbidly obese subjects that are not predicted by the constructed BMI correlation models.
  
  
  METHODS
  Cross-sectional population and longitudinal studies.
  
  
  METHODS
  Bariatric surgery center in a university hospital.
  
  
  METHODS
  A cross-sectional survey of a male general population of 161 patients (BMI median [interquartile range] = 29.2 [24.8-41.9] kg/m(2)) in addition to 24 morbidly obese subjects (BMI = 43.9 [40.8-53.8] kg/m(2)) who were undergoing bariatric surgery were prospectively studied for 6 and 12 months.
  
  
  METHODS
  Bariatric surgery on 24 morbidly obese men.
  
  
  METHODS
  Cross-sectional population: construction of the best-fitting models describing the relationship between baseline BMI with total (TT) and calculated free (cFT) testosterone, E2, sex hormone-binding globulin (SHBG), FSH, and LH levels. Longitudinal study deviation between the observed sex hormone levels at 6- and 12-month follow-up and those expected on BMI bases.
  
  
  RESULTS
  The correlation of BMI with sex hormones was not univocally linear (E2), but the best-fitting model was exponential for TT, cFT, FSH, LH, and TT/E2 and power for SHBG. In addition to the significant improvement of all parameters observed after surgery in the longitudinal cohort, the increase in TT and SHBG, but not in cFT, was significantly higher than expected from the corresponding weight loss at 6 months from surgery (14.80 [12.30-19.00] nM vs. 12.77 [10.92-13.64] nM and 40.0 [28.9-54.5] nM vs. 24.7 [22.5-25.8] nM for TT and SHBG, respectively), remaining rather stable at 12 months.
  
  
  CONCLUSIONS
  The increase in TT and SHBG, but not the increase in cFT, after bariatric surgery is greater than expected based on weight loss.
authors.affiliation: Department of Clinical Physiopathology, Endocrinology Unit, University of Florence, Florence, Italy.
authors.forename: Michaela
authors.initials: M
authors.lastname: Luconi
authors.forename: Jinous
authors.initials: J
authors.lastname: Samavat
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Seghieri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Iannuzzi
authors.forename: Marcello
authors.initials: M
authors.lastname: Lucchese
authors.forename: Carlo
authors.initials: C
authors.lastname: Rotella
authors.forename: Gianni
authors.initials: G
authors.lastname: Forti
authors.forename: Mario
authors.initials: M
authors.lastname: Maggi
authors.forename: Edoardo
authors.initials: E
authors.lastname: Mannucci
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood; D043373:Follicle Stimulating Hormone, Human / Q000097:blood; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009767:Obesity, Morbid / Q000097:blood / Q000175:diagnosis / Q000601:surgery*; D011446:Prospective Studies; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013739:Testosterone / Q000097:blood / Q000172:deficiency*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D043373:Follicle Stimulating Hormone, Human; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol; D007986:Luteinizing Hormone