DXA-Derived Abdominal Adiposity and Obesity-Related Cancer Risk Among Postmenopausal Women in the Women's Health Initiative.

Abstract

Obesity is associated with the risk of several cancers, yet conventional anthropometric measures do not distinguish the contributions of different compartments of abdominal adipose tissue. This study examined the relationship between visceral (VAT) and subcutaneous (SAT) abdominal adiposity and the incidence of 13 obesity-related cancers (ObRCs) in postmenopausal women. Data from 9950 postmenopausal participants in the Women's Health Initiative (WHI) dual-energy X-ray absorptiometry (DXA) cohort were analyzed. Abdominal VAT and SAT were quantified from DXA scans using validated imaging software. Fine and Gray competing-risks models estimated associations with ObRC incidence over 177,295 person-years of follow-up. Higher abdominal VAT was significantly associated with higher ObRC risk, independently of BMI, waist circumference (WC), and other confounders. Each 100-cm² increase in VAT corresponded to a 32% higher risk, with a nearly twofold increase for women in the highest VAT quartile. SAT and the VAT/SAT ratio were also significantly associated with risk, though more modestly. Findings were consistent across BMI, WC, age, and race/ethnicity strata and in time-varying models. Visceral adiposity has a strong, independent association with ObRC risk in postmenopausal women. Incorporating imaging-based body composition measures may improve cancer risk stratification and guide targeted prevention strategies. ClinicalTrials.gov identifier: NCT00000611 https://clinicaltrials.gov/study/NCT00000611.