title: Menstrual and reproductive factors in relation to risk of endometrial cancer in Chinese women.
abstract: Menstrual, reproductive and contraceptive factors have been associated with risk of endometrial cancer in populations where the incidence of this tumor is high. To investigate associations between these factors in a low-risk population with a low prevalence of hormone replacement therapy, we conducted a cohort study among 267,400 women employed in the textile industry in Shanghai, China. Menstrual, reproductive and other factors were ascertained at baseline in 1989-1991, and women were followed for incident endometrial cancer through 31 December 1998 (n = 206). Cox proportional hazards modeling was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Risk of endometrial cancer decreased with increasing age at menarche (p-trend = 0.004). Among menopausal women, risk increased with age at menopause and increasing years of menstruation. Compared to women with one live birth, risk was increased in relation to nulliparity (Hazard ratio = 3.95, 95% CI 1.43-10.86). Risk was decreased with increasing age at first live birth (p-trend = 0.03). There was a decreased risk associated with ever use of an intrauterine device (HR = 0.56, 95% CI 0.35-0.88) and use of oral contraceptives for > or =2 years (HR = 0.50, 95% CI 0.23-1.07). This prospective study confirms findings from previous case-control studies relating menstrual, reproductive, and contraceptive factors and endometrial carcinoma.
authors.affiliation: Program in Epidemiology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. kwernli@fhcrc.org
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Wernli
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Ray
authors.forename: Dao Li
authors.initials: DL
authors.lastname: Gao
authors.forename: Anneclaire J
authors.initials: AJ
authors.lastname: De Roos
authors.forename: Harvey
authors.initials: H
authors.lastname: Checkoway
authors.forename: David B
authors.initials: DB
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D016889:Endometrial Neoplasms / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008572:Menarche; D008593:Menopause; D008875:Middle Aged; D010298:Parity; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors