Background: The risk for breast cancer and the sex hormone abnormalities noted in breast cancer patients have been demonstrated in women with upper body fat obesity. The objective of this study was to determine if the visceral component of upper body fat obesity was correlated with breast cancer risk.
Methods: A case-control study of 40 consecutively enrolled women with breast cancer and 40 community-based age, weight, and waist circumference-matched control subjects was conducted. The areas of visceral fat, subcutaneous fat, and total fat were measured using computed tomography at the L-4 vertebral body. Calculations of relative risk for breast cancer were based on these fat compartments.
Results: Patients with breast cancer had a significantly greater visceral fat area (P = 0.01), visceral-to-total-fat area ratio (VT ratio) (P < 0.001) and significantly lower subcutaneous-to-visceral-fat area ratio (SV ratio) (P < 0.001) compared with the matched controls. The relative risk for breast cancer increased with increasing VT ratio (< or = 0.24 = 1.0; > 0.24 = 9.5) (P < 0.0001) and decreasing SV ratio (> or = 3.64 = 1.0; < 3.64 = 8.5) (P = 0.0002).
Conclusions: Visceral obesity, as assessed by computed tomography, was a significant risk factor for breast cancer in women matched for age, weight, and waist circumference. Comparing the VT ratio for both groups, breast cancer patients had 45% more visceral fat compared with matched control subjects.