title: [Risk factors of prostate cancer in urban Qingdao: a case-control study].
abstract: OBJECTIVE
  To investigate the risk factors of prostate cancer in urban Qingdao and provide some theoretical evidence for the scientific prevention and treatment of the disease.
  
  
  METHODS
  We performed a hospital-based matched case-control study in Qingdao Municipal Hospital. The cases and controls were matched in age, gender, nationality and the place of residence. All the subjects were interviewed face to face in the hospital using a questionnaire, and the data analyzed by the conditional logistic regression method.
  
  
  RESULTS
  According to the 258 valid questionnaires collected, the prostate cancer risk was significantly higher in the cases with a family history of cancer than in those without (OR = 2.58), and so was it in the men with the first spermatorrhea at the age of < or = 15 years than in those at the age of > or = 18 years (OR = 2.27). A decreased risk of prostate cancer was found among the men with the first experience of sexual intercourse between 25 to 30 years of age (OR = 0.76). An increased risk was shown in those with sexual intercourses > or = 4 times per week before 35 years old (OR = 2.57), masturbations > or = 3 times per week (OR = 2.30) and a drinking history (alcohol > or = 150 g/d) of > or = 10 years (OR = 2.83).
  
  
  CONCLUSIONS
  Positive family history of cancer, earlier age of the first spermatorrhea, sexual intercourses > or = 4 times per week before 35 years old, frequent masturbations, and heavy drinking for more than 10 years are risk factors for prostate cancer.
authors.affiliation: Department of Urology, Qingdao Mumicipal Hospital, Qingdao, Shangdong 266071, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Jia
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Sun
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Gao
authors.forename: Lei-Yi
authors.initials: LY
authors.lastname: Zhu
authors.forename: Bo-Wen
authors.initials: BW
authors.lastname: Weng
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Liu
authors.forename: Hai
authors.initials: H
authors.lastname: Zhu
authors.forename: Zhi-Lei
authors.initials: ZL
authors.lastname: Qiu
authors.forename: Si-Chuan
authors.initials: SC
authors.lastname: Hou
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology*; D012307:Risk Factors; D011795:Surveys and Questionnaires