Family history of myocardial infarction is an independent risk factor for venous thromboembolism: the Tromsø study.

BACKGROUND: Recent studies indicate that arterial cardiovascular diseases and venous thromboembolism (VTE) share common risk factors. A family history of myocardial infarction (MI) is a strong and independent risk factor for future MI.

OBJECTIVES: The purpose of the present study was to determine the impact of cardiovascular risk factors, including family history of MI, on the incidence of VTE in a prospective, population-based study.

PATIENTS AND METHODS: Traditional cardiovascular risk factors and family history of MI were registered in 21,330 subjects, aged 25-96 years, enrolled in the Tromsø study in 1994-95. First-lifetime VTE events during follow-up were registered up to 1 September 2007.

RESULTS: There were 327 VTE events (1.40 per 1000 person-years), 138 (42%) unprovoked, during a mean of 10.9 years of follow-up. In age- and gender-adjusted analysis, age [hazard ratio (HR) per decade, 1.97; 95% confidence interval (CI), 1.82-2.12], gender (men vs. women; HR, 1.25; 95% CI, 1.01-1.55), body mass index (BMI; HR per 3 kg m(-2), 1.21; 95% CI, 1.13-1.31), and family history of MI (HR, 1.31; 95% CI, 1.04-1.65) were significantly associated with VTE. Family history of MI remained a significant risk factor for total VTE (HR, 1.27; 95% CI, 1.01-1.60) and unprovoked VTE (HR, 1.46; 95% CI, 1.03-2.07) in multivariable analysis. Blood pressure, total cholesterol, HDL-cholesterol, triglycerides, and smoking were not independently associated with total VTE.

CONCLUSIONS: Family history of MI is a risk factor for both MI and VTE, and provides further evidence of a link between venous and arterial thrombosis.