title: Association of cigarette smoking, alcohol consumption, and physical activity with sex steroid hormone levels in US men.
abstract: BACKGROUND
  We evaluated the associations of smoking, alcohol consumption, and physical activity with sex steroid hormone concentrations among 1,275 men > or =20 years old who participated in the Third National Health and Nutrition Examination Survey (NHANES III).
  
  
  METHODS
  Serum concentrations of testosterone, estradiol, and sex hormone-binding globulin (SHBG) were measured. We compared geometric mean concentrations across levels of smoking, alcohol, and physical activity using multiple linear regression.
  
  
  RESULTS
  Current smokers had higher total testosterone (5.42, 5.10, and 5.26 ng/ml in current, former, and never smokers), free testosterone (0.110, 0.102, and 0.104 ng/ml), total estradiol (40.0, 34.5, and 33.5 pg/ml), and free estradiol (1.05, 0.88, and 0.84 pg/ml) compared with former and never smokers (all p < or = 0.05). Men who consumed > or =1 drink/day had lower SHBG than men who drank less frequently (31.5 vs. 34.8 nmol/l, p = 0.01); total (p-trend = 0.08) and free testosterone (p-trend = 0.06) increased with number of drinks per day. Physical activity was positively associated with total (p-trend = 0.01) and free testosterone (p-trend = 0.05).
  
  
  CONCLUSIONS
  In this nationally representative sample of men, smoking, alcohol, and physical activity were associated with hormones and SHBG, thus these factors should be considered as possible confounders or upstream variables in studies of hormones and men's health, including prostate cancer.
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA.
authors.forename: Meredith S
authors.initials: MS
authors.lastname: Shiels
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Andy
authors.initials: A
authors.lastname: Menke
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Selvin
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Crespo
authors.forename: Nader
authors.initials: N
authors.lastname: Rifai
authors.forename: Adrian
authors.initials: A
authors.lastname: Dobs
authors.forename: Manning
authors.initials: M
authors.lastname: Feinleib
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Platz
mesh_terms: D000328:Adult; D017677:Age Distribution; D000428:Alcohol Drinking; D004958:Estradiol / Q000097:blood*; D006801:Humans; D016014:Linear Models; D008297:Male; D009043:Motor Activity; D009749:Nutrition Surveys; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D012907:Smoking / Q000097:blood*; D013739:Testosterone / Q000097:blood*; D014481:United States
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol