title: Risk factors for epithelial ovarian cancer in Japan - results from the             Japan Public Health Center-based Prospective Study cohort.
abstract: The aim of this study was to evaluate the risk factors for invasive primary             epithelial ovarian cancer among Japanese women. In 1990-1994, 45,748 women aged             40-69 years were enrolled in the Japan Public Health Center-based Prospective             Study cohort. Only 86 epithelial ovarian cancer cases were diagnosed during follow-up             through 2008, reflecting the low ovarian cancer incidence rates in Japan. Cox             proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence             intervals (CI) according to the exposure of interest. The median age at epithelial             ovarian cancer diagnosis was 59 years, with a median follow-up before diagnosis             of 7.6 years. There were no statistically significant associations for age at             menarche or first birth, breastfeeding, use of exogenous hormones, menopausal             status at cohort enrollment, height, body mass index, smoking status, second-hand             smoke, alcohol consumption, physical activity and family history of cancer in             a first-degree relative. The linear decrease in HR associated with each additional             birth was 0.75 (95% CI 0.56-0.99). Among women who usually slept >7 h per day,             an HR of 0.4 (95% CI 0.2-0.9) emerged compared to those who slept <6 h. This             study did not confirm risk factors for epithelial ovarian cancer among Japanese             women that have been reported in studies carried out elsewhere. Usual sleep duration             of >7 h per day was inversely associated with epithelial ovarian cancer risk,             which is a novel finding that needs to be confirmed in other studies.
authors: Karolinska Institutet, Department of Medical Epidemiology and                     Biostatistics, PO Box 281, 171 77 Stockholm, Sweden.
authors: Elisabete
authors: E
authors: Weiderpass
authors: Sven
authors: S
authors: Sandin
authors: Manami
authors: M
authors: Inoue
authors: Taichi
authors: T
authors: Shimazu
authors: Motoki
authors: M
authors: Iwasaki
authors: Shizuka
authors: S
authors: Sasazuki
authors: Norie
authors: N
authors: Sawada
authors: Taiki
authors: T
authors: Yamaji
authors: Shoichiro
authors: S
authors: Tsugane
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000077216:Carcinoma, Ovarian Epithelial; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000453:epidemiology*; D010051:Ovarian Neoplasms / Q000453:epidemiology*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011634:Public Health; D012307:Risk Factors