title: Breast Density and Risk of Breast Cancer in Asian Women: A Meta-analysis of Observational Studies.
abstract: OBJECTIVE
  The established theory that breast density is an independent predictor of breast cancer risk is based on studies targeting white women in the West. More Asian women than Western women have dense breasts, but the incidence of breast cancer is lower among Asian women. This meta-analysis investigated the association between breast density in mammography and breast cancer risk in Asian women.
  
  
  METHODS
  PubMed and Scopus were searched, and the final date of publication was set as December 31, 2015. The effect size in each article was calculated using the interval-collapse method. Summary effect sizes (sESs) and 95% confidence intervals (CIs) were calculated by conducting a meta-analysis applying a random effect model. To investigate the dose-response relationship, random effect dose-response meta-regression (RE-DRMR) was conducted.
  
  
  RESULTS
  Six analytical epidemiology studies in total were selected, including one cohort study and five case-control studies. A total of 17 datasets were constructed by type of breast density index and menopausal status. In analyzing the subgroups of premenopausal vs. postmenopausal women, the percent density (PD) index was confirmed to be associated with a significantly elevated risk for breast cancer (sES, 2.21; 95% CI, 1.52 to 3.21; I2=50.0%). The RE-DRMR results showed that the risk of breast cancer increased 1.73 times for each 25% increase in PD in postmenopausal women (95% CI, 1.20 to 2.47).
  
  
  CONCLUSIONS
  In Asian women, breast cancer risk increased with breast density measured using the PD index, regardless of menopausal status. We propose the further development of a breast cancer risk prediction model based on the application of PD in Asian women.
authors.affiliation: Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Jong-Myon
authors.identifier: 0000-0003-3080-7852
authors.initials: JM
authors.lastname: Bae
authors.affiliation: Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Eun Hee
authors.identifier: 0000-0002-1065-1080
authors.initials: EH
authors.lastname: Kim
mesh_terms: D044466:Asian People; D000071060:Breast Density / Q000502:physiology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology*; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008327:Mammography; D017698:Postmenopause; D012307:Risk Factors
keywords: Breast neoplasms; Mammography; Meta-analysis; Risk factors