HealthDay News — African American women with type 2 diabetes (T2D) appear to be at increased risk of developing estrogen receptor-negative (ER-) breast cancer, with the highest risk among nonobese individuals, according to a study published online in Cancer Research.
Julie R. Palmer, ScD, from Slone Epidemiology Center at Boston University, and colleagues examined the correlation between T2D and incidence of ER- and ER+ breast cancer using data from the Black Women’s Health Study, which enrolled African American women in 1995.
The researchers identified 1851 incident invasive breast cancers during 847,934 person-years of follow-up, including 914 ER+ and 468 ER- cases. For overall breast cancer incidence, the hazard ratio (HR) was 1.18 (95% CI, 1 to 1.4) for T2D versus no T2D; ER- cancer accounted for the increase, with HRs of 1.02 (95% CI, 0.8 to 1.31) and 1.43 (95 percent confidence interval, 1.03 to 2) for ER+ and ER- cancer, respectively. The highest HR for T2D and ER- breast cancer was seen for nonobese women (1.92; 95% CI, 1.22 to 3.04).
“Given the high prevalence of T2D in African American women, the observed association could, in part, explain racial disparities in incidence of ER- breast cancer,” the authors write.
Palmer JR, Castro-Webb N, Bertrand K, Bethea TN, Denis GV. Type II diabetes and incidence of estrogen receptor negative breast cancer in African American women [published online November 15, 2017]. Cancer Res. doi:10.1158/0008-5472.CAN-17-1903