Visceral Adipose Tissue Cut-Points for Increased Metabolic Risk in Chinese Adults using Low Dose Computed Tomography: a Nationwide Multi-Centre Study

Introduction: Visceral adipose tissue (VAT) is a significant driver for metabolic disease risk. Low dose computed tomography (LDCT) imaging obtained for other clinical indications is useful for the opportunistic screening of osteoporosis and demonstrates additional potential for the screening of metabolic risk through the measurement of visceral adipose tissue. In this study, we explored LDCT-derived VAT and calculated VAT thresholds indicative of elevated metabolic risk in a population cohort of Chinese men and women. Methods: A total of 21,772 adults (64.2% men, 35.8% women) received a LDCT chest scan for routine lung cancer screening between 2018 and 2019, and abdominal VAT area (L2 region) was derived from these scans using QCT software. The presence of metabolic syndrome (MetS) was ascertained from clinical records and based on the Chinese national guidelines. All data for this current study were obtained from the China Biobank Project, a prospective, nationwide, multi center population study. Results: MetS was prevalent in 29.5% of men and 10.5% of women. Using ROC curves, the optimum VAT area cut-points to identify MetS were 213 cm2 in men (OR 6.15, 95%CI 5.65 - 6.69) and 136 cm2 in women (OR 9.25, 95%CI 7.58 - 11.4). A further analysis of population attributable risk showed that VAT above threshold was significantly associated with an increased risk for metabolic syndrome. A population attributable risk for MetS by VAT area above sex-specific cut-points was 70.9% in men and 74.1% in women. Conclusion: LDCT-based opportunistic screening could identify patients at increased risk of MetS through the evaluation of VAT area and application of sex-specific VAT cut-points. Future cohort studies are needed to ascertain the clinical utility and health economic benefits of the derived cut-points in terms of the prevention of MetS and associated morbidity and mortality.