title: Psychological stress and testicular function: a cross-sectional study of 1,215 Danish men.
abstract: OBJECTIVE
  To study the associations between self-reported psychological stress, semen quality, and serum reproductive hormones among young Danish men.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  University hospital-based research center.
  
  
  METHODS
  Danish men (median age 19 years) from the general population were investigated from 2008 to 2012.
  
  
  METHODS
  Participants completed a questionnaire on health and lifestyle, including a four-item questionnaire about self-rated stress, had a physical examination performed, delivered a semen sample, and had a blood sample drawn.
  
  
  METHODS
  Semen parameters (semen volume, sperm concentration, and percentages of motile and morphologically normal spermatozoa) and serum levels of reproductive hormones (LH, FSH, T, calculated free T, sex hormone-binding globulin, and inhibin B).
  
  
  RESULTS
  Poorer semen quality was detected among men with self-reported stress scores above an intermediate stress level, in a dose-response manner. For example, men with the highest stress levels had 38% (95% confidence interval [CI] 3%; 61%) lower sperm concentration, 34% (95% CI 59%; 106%) lower total sperm count, and 15% (95% CI 1%; 27%) lower semen volume than men with intermediate stress levels. No significant associations between self-reported stress and levels of reproductive hormones were detected.
  
  
  CONCLUSIONS
  A negative association between self-reported stress and semen quality was detected. If causal, stress may be a contributing factor for suboptimal semen quality among otherwise healthy men.
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Loa
authors.initials: L
authors.lastname: Nordkap
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Tina Kold
authors.initials: TK
authors.lastname: Jensen
authors.affiliation: Department of Public Health, University of Copenhagen, Copenhagen, Denmark; National Research Center for the Working Environment, Copenhagen, Denmark.
authors.forename: Åse Marie
authors.initials: ÅM
authors.lastname: Hansen
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Tina Harmer
authors.initials: TH
authors.lastname: Lassen
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Anne Kirstine
authors.initials: AK
authors.lastname: Bang
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Ulla Nordström
authors.initials: UN
authors.lastname: Joensen
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Blomberg Jensen
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Niels Erik
authors.initials: NE
authors.lastname: Skakkebæk
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark. Electronic address: Niels.Joergensen@rh.regionh.dk.
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
mesh_terms: D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D003718:Denmark / Q000453:epidemiology; D005298:Fertility; D043373:Follicle Stimulating Hormone, Human / Q000097:blood*; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology / Q000523:psychology; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000473:pathology*; D013315:Stress, Psychological / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology / Q000523:psychology; D011795:Surveys and Questionnaires; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D043373:Follicle Stimulating Hormone, Human; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D007986:Luteinizing Hormone
keywords: Stress; normal men; reproductive hormones; semen quality; sperm concentration