title: Investigating reasons for ethnic inequalities in breast cancer survival in New Zealand.
abstract: OBJECTIVE
  This study investigated the role that demographic and tumour factors play in explaining ethnic inequalities in breast cancer survival.
  
  
  METHODS
  Breast cancer cases notified to the New Zealand Cancer Registry (NZCR) from April 2005 to April 2007 were followed up to April 2009. Māori, Pacific and non-Māori/non-Pacific women were categorised according to ethnicity on the NZCR. Deprivation was analysed as quintiles of the New Zealand area-based index of socio-economic position. Relative survival rates were estimated using ethnic-specific life tables. Missing values were imputed and excess mortality modelling was used to estimate the contribution of demographic and tumour factors to ethnic inequalities in survival.
  
  
  RESULTS
  There were 2968 breast cancer cases (76.5% non-Māori/non-Pacific, 17% Māori, and 6.5% Pacific) included and 433 recorded deaths. Relative survival rates at 4 years were 91.5% (95% confidence interval (CI) 89.7 to 92.9) for non-Māori/non-Pacific, 86.2% (CI 80.3 to 90.4) for Māori, and 79.6% (CI 68.2 to 87.2) for Pacific women. Using non-Māori/non-Pacific as the reference group, the age-adjusted hazard ratio (HR) dropped for Māori from 1.76 (CI 1.22 to 2.48) to 1.43 (CI 0.97 to 2.10) when further adjusted by deprivation. For Pacific the HR dropped from 2.49 (CI 1.57 to 3.94) to 1.94 (CI 1.20 to 3.13). Inequalities persisted after adjustment for subtype variables (ER/PR/HER2), but adjusting for access to care variables (extent/size) eliminated the ethnic inequalities in excess mortality.
  
  
  CONCLUSIONS
  Ethnic disparities in breast cancer survival in New Zealand can be attributed to deprivation and differential access to health care rather than differences in breast cancer subtypes.
authors.affiliation: Centre for Public Health Research, Massey University, Private Bag 756, Wellington, New Zealand. f.j.mckenzie@massey.ac.nz
authors.forename: Fiona
authors.initials: F
authors.lastname: McKenzie
authors.forename: Lis
authors.initials: L
authors.lastname: Ellison-Loschmann
authors.forename: Mona
authors.initials: M
authors.lastname: Jeffreys
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000208:ethnology / Q000401:mortality*; D016001:Confidence Intervals; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D015994:Incidence; D007182:Income; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011203:Poverty; D012042:Registries; D018570:Risk Assessment; D012959:Socioeconomic Factors; D016019:Survival Analysis