Insulin Resistance and Inflammation in Black Women with and without Breast Cancer: Cause for Concern.

OBJECTIVE: After chemotherapy for breast cancer, Black women gain more weight and have an increased mortality rate compared with White women. Our study objective was to compare biomarkers associated with obesity in Black women with and without a history of breast cancer.

DESIGN: Case-control.

SETTING: Academic/federal institution.

PARTICIPANTS: Black women with a history of breast cancer (cases) and age-matched controls.

MAIN OUTCOME MEASURES: Insulin resistance (HOMA-IR); inflammation (TNF- α, IL-1b, IL-6, IL-8, CRP); lipids (cholesterol, triglycerides).

METHODS: We compared insulin resistance, inflammation, and lipids in overweight and obese Black women with a history of breast cancer (n=19), age similar controls (n=25), and older controls (n=32). Groups did not differ on mean body mass index (BMI), which was 35.4 kg/m2 , 36.0 kg/m2 , and 33.0 kg/m2 , respectively.

RESULTS: Cases had 1.6 and 1.38 times higher HOMA-IR values compared with age similar and older controls, respectively (P≤.001 for both). TNF- α and IL-1b were significantly higher in cases compared with both control groups (P<.001 for both). IL-6 was also higher in cases compared with age-similar controls (P=.007), and IL-8 was lower in cases compared with older controls (P<.05). Lipids did not differ between cases and either control group.

CONCLUSIONS: Black women with breast cancer were significantly more insulin resistant with increased inflammation compared not only with age similar controls but with women who were, on average, a decade older. These biomarkers of insulin resistance and inflammation may be associated with increased risk of breast cancer recurrence and require ongoing evaluation, especially given the relatively abnormal findings compared with the controls in this underserved group.