title: Habitual alcohol consumption associated with reduced semen quality and changes in reproductive hormones; a cross-sectional study among 1221 young Danish men.
abstract: OBJECTIVE
  Study associations between three measures of alcohol consumption (recent, typical/habitual, binging), semen quality and serum reproductive hormones.
  
  
  METHODS
  Cross-sectional population based study.
  
  
  METHODS
  1221 young Danish men, aged 18-28 years were recruited when they attended a compulsory medical examination to determine their fitness for military service from 2008 to 2012. Total alcohol consumption: (1) in the week preceding (habitual/typical) the visit (recent alcohol intake), (2) in a typical week and (3) frequency of 'binge drinking' (consuming more than 5 units/day)) in the past 30 days was estimated.
  
  
  METHODS
  Semen quality (volume, sperm concentration, total sperm count, and percentages of motile and morphologically normal spermatozoa) and serum concentration of reproductive hormones (follicle-stimulating hormone, luteinising hormone, testosterone, sex hormone binding globulin, oestradiol, free testosterone and inhibin B).
  
  
  RESULTS
  Sperm concentration, total sperm count and percentage of spermatozoa with normal morphology were negatively associated with increasing habitual alcohol intake. This association was observed in men reporting at least 5 units in a typical week but was most pronounced for men with a typical intake of more than 25 units/week. Men with a typical weekly intake above 40 units had a 33% (95% CI 11% to 59%) reduction in sperm concentration compared to men with an intake of 1-5 units/week. A significant increase in serum free testosterone with increasing alcohol consumption the week preceding the visit was found. Binging was not independently associated with semen quality.
  
  
  CONCLUSIONS
  Our study suggests that even modest habitual alcohol consumption of more than 5 units per week had adverse effects on semen quality although most pronounced associations were seen in men who consumed more than 25 units per week. Alcohol consumption was also linked to changes in testosterone and SHBG levels. Young men should be advised to avoid habitual alcohol intake.
authors.affiliation: Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Tina Kold
authors.initials: TK
authors.lastname: Jensen
authors.affiliation: Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: Mads
authors.initials: M
authors.lastname: Gottschau
authors.affiliation: Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: Jens Otto Broby
authors.initials: JO
authors.lastname: Madsen
authors.affiliation: The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anne-Maria
authors.initials: AM
authors.lastname: Andersson
authors.affiliation: The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Tina Harmer
authors.initials: TH
authors.lastname: Lassen
authors.affiliation: The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Niels E
authors.initials: NE
authors.lastname: Skakkebæk
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Shanna H
authors.initials: SH
authors.lastname: Swan
authors.affiliation: Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark.
authors.forename: Lærke
authors.initials: L
authors.lastname: Priskorn
authors.affiliation: The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Juul
authors.affiliation: The Faculty of Medical and Health Sciences, University Department of Growth and Reproduction, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects*; D000437:Alcoholism / Q000150:complications; D063425:Binge Drinking / Q000150:complications; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D004958:Estradiol / Q000097:blood*; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006801:Humans; D007265:Inhibins / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D012661:Semen / Q000187:drug effects; D055101:Semen Analysis; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D013076:Sperm Count; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D012738:Sex Hormone-Binding Globulin; C422364:inhibin B; D013739:Testosterone; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: EPIDEMIOLOGY; PUBLIC HEALTH; REPRODUCTIVE MEDICINE