Race, poverty, affluence, and breast cancer.

Abstract

Nancy Krieger rightly argues that labeling breast cancer a disease of the affluent is simplistic and may lead to correspondingly oversimplified views on screening and prevention.1 We would like to extend her analysis of racial differences in US patterns of breast cancer incidence and mortality to consider the issue of heterogeneity of socioeconomic status within racial categories and the potential relevance of this issue for breast cancer incidence. According to cancer statistics collected by Surveillance, Epidemiology, and End Results (SEER) in the metropolitan Atlanta area, age-specific breast cancer incidence rates in Black women were higher than the corresponding rates in White women in all age groups younger than 55 years in the period 1992 through 1999.2 At older ages, rates in Black and White women were similar. By 1993, the overall age-adjusted incidence rate of breast cancer in Black women in Atlanta had modestly surpassed that of White women, suggesting that the “catch-up” phenomenon described by Krieger is at least a decade old in metropolitan Atlanta. In contrast, in metropolitan Detroit over the same time period, age-specific breast cancer incidence rates for Black and White women conformed to the pattern commonly noted by epidemiologists: Blacks’ rates were modestly higher than Whites’ rates up to the age of 40 years, while Whites’ rates were considerably higher than Blacks’ rates at older ages. Further, Black women in Detroit had lower incidence rates than Black women in Atlanta at all ages.2 Aggregate-level data indicate that Black women in metropolitan Atlanta are of higher socioeconomic status than Black women in other parts of the United States, including Detroit.3 Black women in Atlanta are more likely to be college educated and living above the poverty level than Black women in Detroit, and the total fertility rate (as estimated by the number of children ever born per 1000 women aged 35–44 years) of Black women in Atlanta is lower than that of Black women in Detroit. In some counties in the Atlanta metro area, Black women have a lower total fertility rate than White women, while in Detroit-area counties, Black women have a consistently higher total fertility rate than White women.4,5 This evidence suggests a reality that Krieger has pointed out: broad categorizations of “race” and “socioeconomic status” (SES) hide important heterogeneity within groups that is critical to a deeper understanding of the etiology of breast cancer.6 In many respects, the international data cited by Krieger1 and the data presented here suggest a similar explanation: as reproductive behaviors in different racial and ethnic groups converge to a pattern of later onset of childbearing and fewer births, breast cancer incidence rates similarly converge to the higher rates that have been well described in higher-SES White populations in industrial societies. However, this explanation does not address the higher breast cancer incidence in young Black women compared with young White women that has been observed since 1973, a gap that may be narrowing.2 The labels of “affluence” or “poverty,” when removed from the context of reproductive patterns, likely have little relevance for describing and predicting breast cancer incidence. However, given that there are few known or hypothesized risk factors that serve as accurate screeners of an individual woman’s risk of breast cancer, and given the current lack of broadly acceptable and effective primary prevention strategies against the disease, ensuring access to breast cancer screening and treatment services to all women, regardless of race or SES or reproductive profile, remains an important public health goal.