title: Relationship between physical occupational exposures and health on semen quality: data from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study.
abstract: OBJECTIVE
  To study the relationship among occupation, health, and semen quality in a cohort of men attempting to conceive.
  
  
  METHODS
  Observational prospective cohort.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  A total of 501 couples discontinuing contraception were followed for 1 year while trying to conceive; 473 men (94%) provided one semen sample, and 80% provided a second sample.
  
  
  METHODS
  None.
  
  
  METHODS
  Semen data obtained through at-home semen collection with next-day analysis/quantification.
  
  
  RESULTS
  In all, complete data were available for 456 men, with a mean age of 31.8 years. Work-related heavy exertion was consistently associated with lower semen concentration and total sperm count. Thirteen percent of men who reported heavy exertion displayed oligospermia, compared with 6% who did not report workplace exertion. Shift work, night work, vibration, noise, heat, and prolonged sitting were not associated with semen quality. Men with high blood pressure had significantly lower strict morphology scores compared with normotensive men (17% vs. 21%). In contrast, hyperlipidemia, diabetes, and composite of total comorbidities were not associated with semen quality. The number of medications a man was taking as a proxy of health status was associated with semen quality. There was a negative association between number of medications and sperm count.
  
  
  CONCLUSIONS
  A negative relationship among occupational exertion, hypertension, and the number of medications with semen quality was identified. As these are potentially modifiable factors, further research should determine whether treatment or cessation may improve male fecundity.
authors.affiliation: Departments of Urology and Obstetrics and Gynecology, Stanford University, Stanford, California. Electronic address: eisenberg@stanford.edu.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Eisenberg
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Maryland.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Glotec, Rockville, Maryland.
authors.forename: Aijun
authors.initials: A
authors.lastname: Ye
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Rockville, Maryland.
authors.forename: Germaine M
authors.initials: GM
authors.lastname: Buck Louis
mesh_terms: D000328:Adult; D015897:Comorbidity; D005298:Fertility; D006304:Health Status; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007248:Infertility, Male / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D007587:Job Description; D008137:Longitudinal Studies; D008297:Male; D008824:Michigan / Q000453:epidemiology; D009790:Occupations; D009845:Oligospermia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D010561:Personnel Staffing and Scheduling; D005082:Physical Exertion; D019338:Polypharmacy; D011446:Prospective Studies; D012307:Risk Factors; D012661:Semen / Q000166:cytology*; D013076:Sperm Count; D013094:Spermatozoa / Q000187:drug effects / Q000473:pathology*; D013781:Texas / Q000453:epidemiology; D013997:Time Factors; D016526:Workload; D017132:Workplace
keywords: Male infertility; comorbidity; health; oligospermia; workplace