Abstract 1634: Risk Factors for Venous Thromboembolism: Results From the Copenhagen City Heart Study
Objectives Venous thromboembolism (VTE) (deep vein thrombosis and pulmonary embolism) and atherosclerotic disease (AD) have for many years been considered two different entities. Recent studies, though, have suggested that the two may share risk factors, but much heterogeneity exists between studies. We therefore undertook the hitherto largest prospective cohort study of risk factors for VTE with a focus on AD risk factors.
Methods Data was taken from the Copenhagen City Heart Study; a prospective cohort study started in 1976 with follow up until 2007. Outcome data was retrieved from electronic national registries. Known risk factors and other variables of interest, including clinical and laboratory measurements, lifestyle factors and socioeconomic factors, for both VTE and AD were studied.
Results The study population comprises 18,954 subjects (median follow up: 21.0 years) representing 365,512 person-years of follow-up. During follow-up 992 subjects experienced at least one VTE event, corresponding to a crude incidence rate of 2.71 (95%CI, 2.55–2.89) per 1,000 person-years. The variables found to be significantly associated with VTE in a Cox multivariate model with age as underlying time scale and adjusted for calendar time were: diastolic blood pressure (hazard ratio (HR) for 100 mmHg: 1.33 [95% CI, 1.07–1.64, P=0.009]), body mass index (HR for <20 vs. >35: 2.12 [95%CI, 1.42–3.17, P=0.0003]), smoking (HR for never smoker vs. 25 g tobacco per day: 1.60 [95%CI, 1.22–2.11, P=0.0007]) gender (HR for male vs. female: 1.22 [95%CI 1.06 –1.40, P=0.004]), and household income (HR for low vs. medium: 0.81 [95%CI 0.70 – 0.94, P=0.006]). The well-established AD risk factors; systolic blood pressure and total/HDL/LDL cholesterol levels did not reach significance, and neither was a trend towards this observed.
Conclusions In this, the hitherto largest, study in the field, we found body mass index, diastolic blood pressure, smoking, gender and household income to be risk factors for venous thromboembolism. In conclusion, although some risk factors are shared, important risk factors for AD such as dyslipidemia and systolic blood pressure was not associated with VTE.