Insulin resistance contributes to racial disparities in breast cancer prognosis in US women

A new study in Breast Cancer Research suggests that, among others, insulin resistance is a contributing factor in the association between race and poor prognosis in US women with breast cancer.¹

Although mortality rates have declined in some ethnic populations, the overall cancer incidence among African American and Hispanic populations continue to grow.² The lack of data on the possible connection between race and breast cancer prognosis is what led a group of Mount Sinai researchers to conduct this new multicenter, cross-sectional study.

They used data from 10 hospitals across the country and patients included self-identified black women and white women with newly diagnosed invasive breast cancer. According to the authors, metabolic syndrome disproportionately affects more black women than white women.

The primary goal of the study was to determine if insulin resistance, determined by the homeostatic model assessment of insulin resistance (HOMA-IR), mediated the effect of race on prognosis. Researchers also included demographic data, anthropometric measurements, and fasting blood.

In total, 515 women participated (83% white, 17% black). Researchers ultimately found that MetS was more prevalent in black women than in white women (40% vs. 20%, P=0.0001).

The study also found that the mediation model, when adjusted for age, revealed that HOMA-IR was higher in black women than in white women (1.9± 1.2 vs. 1.3 ± 1.2, p=0.0005).

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References

1. Gallagher EJ, Fei K, Feldman, SM, et al. Insulin resistance contributes to racial disparities in breast cancer prognosis in US women. Breast Cancer Res. 2020;22:40https://doi.org/10.1186/s13058-020-01281-y

2. Yedjou CG, Sims JN, Miele L, et al. Health and racial disparity in breast cancer. Adv Exp Med Biol. 2019;1152:31‐49. doi:10.1007/978-3-030-20301-6_3