title: Risk Factors of Female Breast Cancer in Vietnam: A Case-Control Study.
abstract: OBJECTIVE
  Rates of women with breast cancer have increased rapidly in recent years in Vietnam, with over 10,000 new patients contracting the disease every year. This study was conducted to identify demographic, reproductive and lifestyle risk factors for breast cancer in Vietnam.
  
  
  METHODS
  Breast density, demographic, reproductive and lifestyle data of 269 women with breast cancer and 519 age-matched controls were collected in the two largest oncology hospitals in Vietnam (one in the north and one in the south). Baseline differences between cases and controls in all women, premenopausal and postmenopausal women were assessed using chi-squared tests and independent t tests. Conditional logistic regression was used to derive odds ratios (OR) for factors that had statistically significant associations with breast cancer.
  
  
  RESULTS
  Vietnamese women with breast cancer were significantly more likely to have a breast density > 75% (OR, 1.7), be younger than 14 years at first menstrual period (OR, 2.2), be postmenopausal (OR, 2.0), have less than three pregnancies (OR, 2.1), and have less than two babies (OR, 1.7). High breast density (OR, 1.6), early age at first menstrual period (OR, 2.6), low number of pregnancies (OR, 2.3), hormone use (OR, 1.8), and no physical activities (OR, 2.2) were significantly associated with breast cancer among premenopausal women, while breast density (OR, 2.0), age at first menstrual period (OR, 1.8), number of pregnancies (OR, 2.3), and number of live births (OR, 2.4) were the risk factors for postmenopausal women.
  
  
  CONCLUSIONS
  Breast density, age at first menarche, menopause status, number of pregnancies, number of babies born, hormone use and physical activities were significantly associated with breast cancer in Vietnamese women.
authors.affiliation: Faculty of Health Sciences, The University of Sydney, New South Wales, Australia.|University of Medicine and Pharmacy, Ho Chi Minh City, Vietnam.
authors.forename: Phuong Dung Yun
authors.initials: PDY
authors.lastname: Trieu
authors.affiliation: Faculty of Health Sciences, The University of Sydney, New South Wales, Australia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mello-Thoms
authors.affiliation: Australian Catholic University, Queensland, Australia.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Peat
authors.affiliation: Department of Diagnostic Imaging, Vietnam National Cancer Hospital, Hanoi, Vietnam.
authors.forename: Thuan Doan
authors.initials: TD
authors.lastname: Do
authors.affiliation: Faculty of Health Sciences, The University of Sydney, New South Wales, Australia.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Brennan
mesh_terms: D000328:Adult; D000071060:Breast Density; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008019:Life Style; D008593:Menopause; D008875:Middle Aged; D016017:Odds Ratio; D011159:Population Surveillance; D012098:Reproduction; D012307:Risk Factors; D014744:Vietnam / Q000453:epidemiology
keywords: Breast neoplasms; Case-control studies; Demography; Life style; Reproductive behaviour; Risk factors