title: Reduced-calorie dietary weight loss, exercise, and sex hormones in postmenopausal women: randomized controlled trial.
abstract: OBJECTIVE
  Estrogens and androgens are elevated in obesity and associated with increased postmenopausal breast cancer risk, but the effect of weight loss on these biomarkers is unknown. We evaluated the individual and combined effects of a reduced-calorie weight loss diet and exercise on serum sex hormones in overweight and obese postmenopausal women.
  
  
  METHODS
  We conducted a single-blind, 12-month, randomized controlled trial from 2005 to 2009. Participants (age 50 to 75 years; body mass index > 25.0 kg/m(2), exercising < 100 minutes/wk) were randomly assigned using a computer-generated sequence to (1) reduced-calorie weight loss diet ("diet"; n = 118), (2) moderate- to vigorous-intensity aerobic exercise ("exercise"; n = 117), (3) combined reduced-calorie weight loss diet and moderate- to vigorous-intensity aerobic exercise ("diet + exercise"; n = 117), or (4) control (n = 87). Outcomes were estrone concentration (primary) and estradiol, free estradiol, total testosterone, free testosterone, androstenedione, and sex hormone-binding globulin (SHBG) concentrations (secondary).
  
  
  RESULTS
  Mean age and body mass index were 58 years and 30.9 kg/m(2), respectively. Compared with controls, estrone decreased 9.6% (P = .001) with diet, 5.5% (P = .01) with exercise, and 11.1% (P < .001) with diet + exercise. Estradiol decreased 16.2% (P < .001) with diet, 4.9% (P = .10) with exercise, and 20.3% (P < .001) with diet + exercise. SHBG increased 22.4% (P < .001) with diet and 25.8% (P < .001) with diet + exercise. Free estradiol decreased 21.4% (P < .001) with diet and 26.0% (P < .001) with diet + exercise. Free testosterone decreased 10.0% (P < .001) with diet and 15.6% (P < .001) with diet + exercise. Greater weight loss produced stronger effects on estrogens and SHBG.
  
  
  CONCLUSIONS
  Weight loss significantly lowered serum estrogens and free testosterone, supporting weight loss for risk reduction through lowering exposure to breast cancer biomarkers.
authors.affiliation: University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Campbell
authors.forename: Karen E
authors.initials: KE
authors.lastname: Foster-Schubert
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Alfano
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Wang
authors.forename: Ching-Yun
authors.initials: CY
authors.lastname: Wang
authors.forename: Catherine R
authors.initials: CR
authors.lastname: Duggan
authors.forename: Caitlin
authors.initials: C
authors.lastname: Mason
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Imayama
authors.forename: Angela
authors.initials: A
authors.lastname: Kong
authors.forename: Liren
authors.initials: L
authors.lastname: Xiao
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Bain
authors.forename: George L
authors.initials: GL
authors.lastname: Blackburn
authors.forename: Frank Z
authors.initials: FZ
authors.lastname: Stanczyk
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D000368:Aged; D000728:Androgens / Q000097:blood*; D015992:Body Mass Index; D004038:Diet, Reducing / Q000379:methods*; D004967:Estrogens / Q000097:blood*; D015444:Exercise; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D012307:Risk Factors; D016037:Single-Blind Method
chemical_list: D000728:Androgens; D004967:Estrogens; D012739:Gonadal Steroid Hormones