title: Association of serum calcium with serum sex steroid hormones in men in NHANES III.
abstract: BACKGROUND
  Bone is a positive regulator of male fertility, which indicates a link between regulation of bone remodeling and reproduction or more specifically a link between calcium and androgens. This possibly suggests how calcium is linked to prostate cancer development through its link with the reproductive system. We studied serum calcium and sex steroid hormones in the Third National Health and Nutrition Examination Survey (NHANES III).
  
  
  METHODS
  Serum calcium and sex steroid hormones were measured for 1262 men in NHANES III. We calculated multivariable-adjusted geometric means of serum concentrations of total and estimated free testosterone and estradiol, androstanediol glucuronide (AAG), and sex hormone binding globulin (SHBG) by categories of calcium (lowest 5% [<1.16 mmol/L], mid 90%, top 5% [≥1.30 mmol/L]).
  
  
  RESULTS
  Levels of total and free testosterone, total estradiol or AAG did not differ across categories of serum calcium. Adjusted SHBG concentrations were 36.4 for the bottom 5%, 34.2 for the mid 90% and 38.9 nmol/L for the top 5% of serum calcium (Ptrend = 0.006), free estradiol levels were 0.88, 0.92 and 0.80 pg/ml (Ptrend = 0.048).
  
  
  CONCLUSIONS
  This link between calcium and sex steroid hormones, in particular the U-shaped pattern with SHBG, may, in part, explain why observational studies have found a link between serum calcium and risk of prostate cancer.
authors.affiliation: Division of Cancer Studies, Cancer Epidemiology Group, School of Medicine, King's College London , London , UK .
authors.forename: Mieke
authors.initials: M
authors.lastname: Van Hemelrijck
authors.forename: Karl
authors.initials: K
authors.lastname: Michaelsson
authors.forename: William G
authors.initials: WG
authors.lastname: Nelson
authors.forename: Norma
authors.initials: N
authors.lastname: Kanarek
authors.forename: Adrian
authors.initials: A
authors.lastname: Dobs
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
mesh_terms: D001842:Bone and Bones / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000378:metabolism; D018570:Risk Assessment; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D013223:Statistics as Topic
chemical_list: D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin; D002118:Calcium