Race, anthropometric factors, and stage at diagnosis of breast cancer.

A recent study suggested that the greater prevalence of severe obesity among African-American women explained almost one third of the observed differences between African-American and White women in stage at diagnosis of breast cancer. The objective of this investigation was to attempt to replicate these findings in a second, larger population and to expand the analyses by including a measure of body fat distribution, the waist:hip ratio. The authors used data from a population-based study in North Carolina comprising 791 breast cancer cases (302 in African-American women and 489 in White women) diagnosed between 1993 and 1996. African-American women were more likely to have later-stage (TNM stage >/=II) breast cancer (odds ratio (OR) = 2.2; 95% confidence interval (CI): 1.6, 2.9). They also were much more likely to be severely obese (body mass index >/=32.3) (OR = 9.7; 95% CI: 6.5, 14.5) and to be in the highest tertile of waist:hip ratio (OR = 5.7; 95% CI: 3.8, 8.6). In multivariate logistic regression models, adjustment for waist:hip ratio reduced the odds ratio for later-stage disease in African-American women by 20%; adjustment for both waist:hip ratio and severe obesity reduced the odds ratio by 27%. These observations suggest that obesity and body fat distribution, in addition to socioeconomic and medical care factors, contribute to racial differences in stage at breast cancer diagnosis.

Duke Scholars

Author Patricia Gripka Moorman Family Medicine and Community Health, Prevention Research