title: Parity and risk of death from lung cancer among a cohort of premenopausal parous women in Taiwan.
abstract: BACKGROUND
  We examined the association between parity and risk of lung cancer.
  
  
  METHODS
  The study cohort consisted of all women with a record of a first singleton birth in the Taiwanese Birth Register between 1978 and 1987. We tracked each woman from the time of their first childbirth to 31 December 2009. Follow-up was terminated when the mother died, when she reached age 50 years, or on 31 December 2009, whichever occurred first. The vital status of mothers was ascertained by linking records with the computerized mortality database. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) for death from lung cancer associated with parity.
  
  
  RESULTS
  There were 1375 lung cancer deaths during 32 243 637.08 person-years of follow-up. The mortality rate of lung cancer was 4.26 cases per 100,000 person-years. As compared with women who had given birth to only 1 child, the adjusted HR was 1.13 (95% CI, 0.94-1.35) for women who had 2 children, 1.10 (0.91-1.33) for those who had 3 children, and 1.22 (0.96-1.54) for those who had 4 or more children.
  
  
  CONCLUSIONS
  The findings suggest that premenopausal women of higher parity tended to have an increased risk of lung cancer, although the trend was not statistically significant.
authors.affiliation: Division of Pulmonary and Critical Medicine, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Meng-Hsuan
authors.initials: MH
authors.lastname: Cheng
authors.forename: Shang-Shyue
authors.initials: SS
authors.lastname: Tsai
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Chen
authors.forename: Shu-Chen
authors.initials: SC
authors.lastname: Ho
authors.forename: Hui-Fen
authors.initials: HF
authors.lastname: Chiu
authors.forename: Trong-Neng
authors.initials: TN
authors.lastname: Wu
authors.forename: Chun-Yuh
authors.initials: CY
authors.lastname: Yang
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality*; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D017697:Premenopause; D018570:Risk Assessment; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult