Abstract 129: Race-specific social gradients in breast cancer burden in Maryland: 1992-2003.

Abstract

There is substantial evidence linking adverse breast cancer characteristics, including more aggressive histology, larger tumor size, and advanced stage at diagnosis, to both African American race, and lower social class. However, it is not well known if social class affects black and white women similarly, and what behavioral or environmental factors may contribute to the social class gradient for each racial group. Using data from approximately 55,000 cases of breast cancer reported to the Maryland Cancer Registry between 1992-2003, we used multi-level random effects models to examine the relationship between case race, age, year of diagnosis, area-level social class indices (area-level rates of high school graduation, employment, white collar work, and income) and three characteristics associated with adverse cancer outcomes: SEER stage at diagnosis (stage 2-7 versus 1), large tumor size at diagnosis (>2 cm versus <=2 cm), and aggressive histological grade of tumor (grade 3 or 4, versus 1 or 2). We then examined the additional contribution to the model of an estimate of area-level smoking behavior, using estimates of area-level average per household tobacco spending. Finally, we examined whether effects of social class and tobacco use varied for white and black women. Results demonstrate that black women were more likely to be diagnosed with later stage cancers (O.R. =1.29, 95% C.I.= 1.22,1.35), larger tumors (O.R.= 1.45, 95% C.I.= 1.34, 1.56), and more aggressive tumor histology (O.R. 1.65, 95% C.I.= 1.56,1.74). Social class was protective for all three outcomes, but statistically significant interactions showed that this protective effect of social class was reduced for black women compared to white women. In addition, each $1000 increase in average household level of tobacco spending was significantly associated with aggressive grade (O.R.=1.01 per $1000) and larger tumor size (O.R. =1.03, 95% C.I.=1.01,1.06) but not significantly associated with late stage diagnosis. There were no statistically significant interactions of tobacco spending by race, indicating that the effect of tobacco spending are similar for black and white cases. Findings suggest that social class effects differ by race, and that intersectionality - the context-based understanding of multiple simultaneous social effects on health - may be an important approach to understanding excess breast cancer burden in women. This analysis also suggests that health risk behaviors, such as group-level tobacco use, may contribute additional risk, and should be further explored with more robust designs and data. Citation Format: Ann C. Klassen, Aaron Pankiewicz, Frank Curriero. Race-specific social gradients in breast cancer burden in Maryland: 1992-2003. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 129. doi:10.1158/1538-7445.AM2013-129