Issue of Waist Circumference for the Diagnosis of Metabolic Syndrome Regarding Arterial Stiffness: Possible Utility of a Body Shape Index in Middle-Aged Nonobese Japanese Urban Residents Receiving Health Screening

Introduction: Abdominal obesity as a risk factor for diagnosing metabolic syndrome (MetS) is evaluated using waist circumference (WC), although WC does not necessarily reflect visceral adiposity. This cross-sectional study aimed to clarify whether replacing WC with "A Body Shape Index (ABSI)," an abdominal obesity index, in MetS diagnosis detects individuals with arterial stiffening assessed by cardio-ankle vascular index (CAVI). Methods: A retrospective cross-sectional study was conducted in 46,872 Japanese urban residents (median age 40 years) who underwent health screening. Exclusion criteria were current treatments and a past history of cardiovascular disease (CVD). The Japanese, International Diabetes Federation, and NCEP-ATPIII criteria were used to diagnose MetS. High CAVI was defined as CAVI >= 9.0. Results: CAVI correlated positively with ABSI (beta = 0.127), but negatively with WC (beta = -0.186), independent of age, sex, systolic blood pressure, fasting plasma glucose, and high-density lipoprotein--cholesterol. Receiver operating characteristic (ROC) analysis showed that ABSI had a stronger contribution to high CAVI (area under the ROC curve [AUC] = 0.730) than WC (AUC = 0.595) and body mass index (AUC = 0.520). ABSI >= 0.080 was defined as abdominal obesity based on the results of ROC analysis for high CAVI and estimated glomerular filtration rate Discussion/Conclusion: Use of ABSI can detect subjects with arterial stiffening, which may lead to efficient stratification of CVD risk. Further studies are needed to confirm whether MetS diagnosis using ABSI predicts CVD morbidity and mortality.