title: Semen quality of 1346 healthy men, results from the Chongqing area of southwest China.
abstract: BACKGROUND
  Large studies on semen quality of the general healthy population from China are rare.
  
  
  METHODS
  A cross-sectional study was performed to evaluate the semen quality of 1346 healthy men residing in Chongqing area of southwest China in 2007. The semen parameters were measured and compared with the World Health Organization (WHO) criteria. A linear regression model was used to examine the determinants of semen quality.
  
  
  RESULTS
  The medians were 2.3 ml for semen volume, 77.8 x 10(6) per ml for semen concentration, 167.7 x 10(6) for total sperm count, 33% for sperm rapid progressive motility, 52.6% for sperm progressive motility and 70.9% for total motility. According to WHO criteria, 61.1% of healthy males had at least one semen parameter below normal threshold values. Season and abstinence duration were found to be significantly associated with semen quality (P < 0.001). Age, smoking, alcohol use and BMI had little or no effect on semen parameters.
  
  
  CONCLUSIONS
  A high proportion of healthy males in Chongqing area of southwest China had abnormal semen parameters values according to WHO criteria. The semen parameters in the study population were markedly different from those reported for the other Chinese, USA and European populations. The differences remain unexplained and may be due to demographic characteristics, lifestyle, environmental factors or genetic variation.
authors.affiliation: Department of Epidemiology, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, People's Republic of China.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Lin
authors.forename: Mingfu
authors.initials: M
authors.lastname: Ma
authors.forename: Lianbing
authors.initials: L
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Cai
authors.forename: Niya
authors.initials: N
authors.lastname: Zhou
authors.forename: Xue
authors.initials: X
authors.lastname: Han
authors.forename: Huaqiong
authors.initials: H
authors.lastname: Bao
authors.forename: Liping
authors.initials: L
authors.lastname: Huang
authors.forename: Caizhong
authors.initials: C
authors.lastname: Zhu
authors.forename: Chuanhai
authors.initials: C
authors.lastname: Li
authors.forename: Hao
authors.initials: H
authors.lastname: Yang
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Rao
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiang
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Cui
authors.forename: Lin
authors.initials: L
authors.lastname: Ao
authors.forename: Ziyuan
authors.initials: Z
authors.lastname: Zhou
authors.forename: Hongyan
authors.initials: H
authors.lastname: Xiong
authors.forename: Jia
authors.initials: J
authors.lastname: Cao
mesh_terms: D000328:Adult; D002681:China; D003430:Cross-Sectional Studies; D005298:Fertility; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012621:Seasons; D012746:Sexual Abstinence; D013076:Sperm Count; D013081:Sperm Motility; D013997:Time Factors