Association between body mass index, waist circumference, and relative fat mass with the risk of first unprovoked venous thromboembolism

Background and aims: Obesity defined by body mass index (BMI) is independently associated with venous thromboembolism (VTE). Abdominal obesity, defined by waist circumference, is a predictor of cardiovascular events. Recently, relative fat mass (RFM) was proposed as a marker of cardiovascular risk. We assessed the role of three different measures of obesity to predict unprovoked VTE in a longitudinal study. Methods and results: Moli-sani is a prospective cohort study carried out in the general population of the Molise region, Italy. A total of 23,538 individuals (48% men, age 55.4 years) enrolled between 2005 and 2010 were eligible. Patients on anticoagulant treatment were excluded. BMI >30 kg/m2 defined obesity, waist circumference >102 cm for men or 88 cm for women defined abdominal obesity, tertiles of RFM were compared. The long-term incidence of first unprovoked VTE during follow-up was assessed. Overall, 29.6% individuals were obese and 44.2% had abdominal obesity. A total of 66 first unprovoked VTE events were diagnosed during a median follow-up of 8.2 years. After multivariable Cox regression analysis, the risk of unprovoked VTE was significantly higher in obese participants (HR 1.89, 95% CI 1.16-3.07) than in participants with BMI <30; in subjects with abdominal obesity than with normal waist circumference (HR 2.19, 1.26 -3.81); and in subjects with third vs first RFM tertile index (HR 2.46, 1.15-5.28). The areas under the curves for the models including the three obesity indexes were comparable. Conclusions: Three indexes of obesity based on BMI, waist circumference or RFM similarly predict first occurrence of unprovoked VTE. (c) 2021 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.