title: Meat intake and reproductive parameters among young men.
abstract: BACKGROUND
  In the United States, anabolic sex steroids are administered to cattle for growth promotion. There is concern regarding the reproductive consequences of this practice in men who eat beef. We investigated whether meat consumption was associated with semen quality parameters and reproductive hormone levels in young men.
  
  
  METHODS
  Semen samples were obtained from 189 men aged 18-22 years. Diet was assessed with a previously validated food frequency questionnaire. We used linear regression to analyze the cross-sectional associations of meat intake with semen quality parameters and reproductive hormones while adjusting for potential confounders.
  
  
  RESULTS
  There was an inverse relation between processed red meat intake and total sperm count. The adjusted relative differences in total sperm counts for men in increasing quartiles of processed meat intake were 0 (ref), -3 (95% confidence interval = -67 to 37), -14 (-82 to 28), and -78 (-202 to -5) million (test for trend, P = 0.01). This association was strongest among men with abstinence time less than 2 days and was driven by a strong inverse relation between processed red meat intake and ejaculate volume (test for trend, P = 0.003).
  
  
  CONCLUSIONS
  In our population of young men, processed meat intake was associated with lower total sperm count. We cannot distinguish whether this association is because of residual confounding by abstinence time or represents a true biological effect.
authors.affiliation: From the aDepartment of Nutrition, bDepartment of Biostatistics, and cDepartment of Epidemiology, Harvard School of Public Health, Boston, MA; d Division of Preventive Medicine and Public Health, University of Murcia School of Medicine, Murcia, Spain; eUniversity Department of Growth and Reproduction, University of Copenhagen, Rigshospitalet, Copenhagen, Denmark; fDepartment of Obstetrics and Gynecology, School of Medicine, University of Rochester, Rochester, NY; gDepartment of Preventive Medicine, Mount Sinai School of Medicine, New York, NY; and hChanning Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors.forename: Myriam C
authors.initials: MC
authors.lastname: Afeiche
authors.forename: Paige L
authors.initials: PL
authors.lastname: Williams
authors.forename: Audrey J
authors.initials: AJ
authors.lastname: Gaskins
authors.forename: Jaime
authors.initials: J
authors.lastname: Mendiola
authors.forename: Niels
authors.initials: N
authors.lastname: Jørgensen
authors.forename: Shanna H
authors.initials: SH
authors.lastname: Swan
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Chavarro
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D000731:Androstanes / Q000009:adverse effects / Q000494:pharmacology; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005247:Feeding Behavior; D006801:Humans; D015994:Incidence; D007248:Infertility, Male / Q000097:blood / Q000453:epidemiology* / Q000209:etiology; D016014:Linear Models; D008297:Male; D008461:Meat Products / Q000009:adverse effects*; D015596:Nutrition Assessment; D012098:Reproduction / Q000502:physiology; D018570:Risk Assessment; D055101:Semen Analysis; D013076:Sperm Count; D013081:Sperm Motility / Q000187:drug effects*; D011795:Surveys and Questionnaires; D013739:Testosterone / Q000097:blood* / Q000378:metabolism; D014481:United States; D055815:Young Adult
chemical_list: D000731:Androstanes; D013739:Testosterone