The Effect of Patient and Contextual Characteristics on Racial/Ethnic Disparity in Breast Cancer Mortality

Cancer Epidemiol Biomarkers Prev. 2016 Jul;25(7):1064-72. doi: 10.1158/1055-9965.EPI-15-1326. Epub 2016 Apr 26.

Abstract

Background: Racial/ethnic disparity in breast cancer-specific mortality in the United States is well documented. We examined whether accounting for racial/ethnic differences in the prevalence of clinical, patient, and lifestyle and contextual factors that are associated with breast cancer-specific mortality can explain this disparity.

Methods: The California Breast Cancer Survivorship Consortium combined interview data from six California-based breast cancer studies with cancer registry data to create a large, racially diverse cohort of women with primary invasive breast cancer. We examined the contribution of variables in a previously reported Cox regression baseline model plus additional contextual, physical activity, body size, and comorbidity variables to the racial/ethnic disparity in breast cancer-specific mortality.

Results: The cohort comprised 12,098 women. Fifty-four percent were non-Latina Whites, 17% African Americans, 17% Latinas, and 12% Asian Americans. In a model adjusting only for age and study, breast cancer-specific HRs relative to Whites were 1.69 (95% CI, 1.46-1.96), 1.00 (0.84-1.19), and 0.52 (0.33-0.85) for African Americans, Latinas, and Asian Americans, respectively. Adjusting for baseline-model variables decreased disparity primarily by reducing the HR for African Americans to 1.13 (0.96-1.33). The most influential variables were related to disease characteristics, neighborhood socioeconomic status, and smoking status at diagnosis. Other variables had negligible impact on disparity.

Conclusions: Although contextual, physical activity, body size, and comorbidity variables may influence breast cancer-specific mortality, they do not explain racial/ethnic mortality disparity.

Impact: Other factors besides those investigated here may explain the existing racial/ethnic disparity in mortality. Cancer Epidemiol Biomarkers Prev; 25(7); 1064-72. ©2016 AACR.

MeSH terms

  • African Americans / statistics & numerical data
  • Asian Americans / statistics & numerical data
  • Body Size
  • Breast Neoplasms / ethnology
  • Breast Neoplasms / mortality*
  • California / epidemiology
  • Cohort Studies
  • Comorbidity
  • European Continental Ancestry Group / statistics & numerical data
  • Exercise
  • Female
  • Healthcare Disparities*
  • Hispanic Americans / statistics & numerical data
  • Humans
  • Proportional Hazards Models
  • Risk Factors