DXA-Derived Visceral and Subcutaneous Adipose Tissue and Postmenopausal Breast Cancer Mortality

Background: Elevated abdominal adipose tissue at time of diagnosis is associated with breast cancer mortality. We sought to understand the association between abdominal adipose tissue (subcutaneous, SAT and visceral, VAT) assessed via dual-energy X-ray absorptiometry (DXA) and breast cancer mortality in the prevention setting. Methods: Women enrolled in the Women’s Health Initiative study with baseline whole-body DXA scans were included in the study (n = 9767). Causes of death were adjudicated up to 27 years of follow-up. Competing risk models were used to examine independent associations between baseline VAT, SAT, per 100 cm², and breast cancer-specific deaths; findings were reported as sub-hazard ratios (SHR) and confidence intervals (CI). Time-varying analyses additionally included DXA at years 3 and 6. Covariates included demographic, lifestyle, and tumor factors. Results: Baseline VAT and SAT ranged from undetectable to 616.25 cm² and 55.26–952.46 cm², respectively. There were 738 incident breast cancer cases post-enrollment, and 87 breast cancer-related deaths. Median age at diagnosis was 62 years. In adjusted models, higher baseline VAT and SAT were significantly associated with higher risk breast cancer mortality (49% and 40%, respectively); time-varying models were similar. Conclusions: Higher VAT and SAT were similarly associated with breast cancer mortality in this group of postmenopausal women.