Metabolic syndrome and risk of venous thromboembolism: Longitudinal Investigation of Thromboembolism Etiology

Background: In a recent case-control study, the odds of metabolic syndrome (MetSyn) among deep vein thrombosis cases were almost twice those among controls. We tested the hypothesis that the incidence of non-cancer-related venous thromboembolism (VTE) is higher among adults with MetSyn and further, that associations are stronger for idiopathic than secondary VTE. Methods: A total of 20374 middle-aged and elderly adults were followed for over 12 years for incident VTE in the Longitudinal Investigation of Thromboembolism Etiology (LITE). All hospitalizations were identified and VTEs validated by chart review. Baseline MetSyn was defined using ATP III guidelines, including ≥3 of the following components: abdominal obesity, elevated blood pressure, low HDL-cholesterol, high triglycerides and high glucose. Because sex modified the relation between MetSyn and VTE (p interaction = 0.001), proportional hazards regression analyses were stratified by sex to assess the associations of MetSyn and its components with risk of incident non-cancer-related VTE, adjusting for potential confounders. Results: Incident VTE (n = 358) included 196 idiopathic events. Baseline MetSyn was associated with risk of total VTE (hazard ratio (HR) = 1.84, 95% CI = 1.30, 2.59) and idiopathic VTE (HR = 1.59, 95% CI = 1.02, 2.47) among men, but not women. The association was largely attributable to abdominal obesity (HR of VTE=2.10, 95% CI = 1.51, 2.93, in men; HR of VTE = 1.70, 95% CI = 1.24, 2.34, in women), with no additional contribution by the other MetSyn components. Conclusion: Although abdominal obesity was associated with increased risk of VTE in both men and women, MetSyn and its other components do not seem important in VTE etiology.