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

## TL;DR

This study finds that both deep belly fat and surface belly fat are equally linked to higher breast cancer death risk in postmenopausal women.

## Contribution

Shows visceral and subcutaneous abdominal fat are similarly associated with breast cancer mortality in the prevention setting.

## Key findings

- Higher baseline visceral and subcutaneous adipose tissue were each linked to 49% and 40% increased breast cancer mortality risk.
- Time-varying models confirmed similar associations between belly fat and mortality over time.
- 738 breast cancer cases and 87 breast cancer-related deaths were observed over 27 years of follow-up.

## Abstract

Prior research shows that higher levels of body fat, particularly deep belly fat that hugs the organs, can increase the risk of postmenopausal breast cancer. After a breast cancer diagnosis, belly fat has also been implicated in death. However, it is unclear if belly fat increases the risk of dying from breast cancer among women that have never been diagnosed with cancer before. This study showed that greater amounts of fat in two different fat compartments in the belly (i.e., surface subcutaneous and deep visceral) were equally associated with death from breast cancer. Future studies are needed to determine if these detailed measurements of belly fat are necessary for prediction of death from breast cancer or if simple measures like BMI and waist circumference are sufficient.

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.