doi: 10.1161/01.ATV.0000157142.64490.e9
© 2005 American Heart Association, Inc.
Letters to the Editor |
Dyslipidemia and Thrombosis: Causal Relationship or Epiphenomenon of Sedentary Lifestyle?
Innsbruck Medical University, Innsbruck, Austria
An extract of the first 250 words of the full text is provided, because this article has no abstract. |
To the Editor:
Doggen et al report that low HDL cholesterol and high triglyceride levels are associated with an increased risk for venous thrombosis in a population-based case–control study. The authors explain their results with an interaction of triglycerides with different coagulant factors as activated protein C (APC), factor VIIc, factor VIII, factor IX, and fibrinogen.1 However, low HDL cholesterol and high triglycerides are found frequently in subjects with a predominantly sedentary lifestyle and are key features of the metabolic syndrome.2 Individuals with the metabolic syndrome are characterized by prothrombotic hemostatic abnormalities such as elevated plasma fibrinogen, elevated factor VIIc, and raised concentrations of plasminogen activator inhibitor (PAI).3 Regular aerobic exercise leads to an improved metabolism of serum lipids with increased levels of HDL cholesterol and decreased plasma triglycerides, resulting in a lower risk of atherothrombotic events.4 Moreover, a recent publication shows that moderate-intensity aerobic exercise leads to a decreased platelet coagulation, hematocrit and blood viscosity, and PAI 1 antigen.5 All these factors are beneficial to hemostatic balance and presumably reduce the risk for thromboembolic events. However, Doggen et al provide no data on physical activity and basic hematologic parameters such as hematocrit.
We suggest that the reported association of low HDL cholesterol and hypertriglyceridemia with thrombosis might be explained, besides the pathomechanisms discussed by Doggen et al,1 in part by lower physical activity resulting in a procoagulant state with increased coagulant factors and higher blood viscosity.
1. Doggen CJM, Smith NL, Lemaitre RN, Heckbert SR, Rosendaal FR, Psaty BM. Serum lipid levels and the risk of venous thrombosis. Arterioscler Thromb Vasc Biol. 2004; 24: 1970–1975.
2. Grundy SM, Brewer HB Jr, Cleeman JI, Smith SC Jr, Lenfant C, for the Conference Participants. Definition of metabolic syndrome: report of the National Heart, Lung, and Blood Institute/American Heart association conference on scientific issues related to definition. Arterioscler Thromb Vasc Biol. 2004; 24: 13–18.
3. Marckmann P. dietary treatment of thrombogenic disorders related to the metabolic syndrome. Br J Nutr. 2000; 83 (Suppl 1): S121–S126.
4. Foger B, Patsch JR. Exercise and postprandial lipaemia. J Cardiovasc Risk. 1995; 2: 316–322.[CrossRef][Medline] [Order article via Infotrieve]
5. Coppola L, Grassia A, Coppola A, Tondi G, Peluso G, Mordente S, Gombos G. Effects of a moderate-intensity aerobic program on blood viscosity, platelet aggregation and fibrinolytic balance in young and middle-aged sedentary subjects. Blood Coagul Fibrinolysis. 2004; 15: 31–37.[CrossRef][Medline] [Order article via Infotrieve]
In response:
Departments of Epidemiology (C.J.M.D., N.L.S., S.R.H., F.R.R., B.M.P.), Medicine (R.N.L., B.M.P.), and Health Services (B.M.P.), University of Washington, Seattle; and the Departments of Clinical Epidemiology (C.J.M.D., F.R.R.) and Hematology (F.R.R.), Leiden University Medical Center, Leiden, the Netherlands
We thank the authors for their interest in our study, in which we