Background A high D‐dimer level and parameters of the thrombin generation (TG) potential are associated with the risk of a first venous thrombosis (VT) in young and middle‐aged populations. Objectives To investigate whether D‐dimer and TG potential (lag‐time, time‐to‐peak [ttPeak], peak thrombin, endogenous thrombin potential [ETP], and velocity index), are associated with the risk of a first VT in those aged 70 years and older. Methods We included 215 patients with a first VT and 358 controls, all aged >70 years, from the Age and Thrombosis, Acquired and Genetic Risk Factors in the Elderly (AT‐AGE) study. To assess the risk of VT, odds ratios with 95% confidence intervals (CIs) were estimated using logistic regression analysis. Results D‐dimer and all TG parameters except lag time were associated with an increased risk of VT in a dose‐response manner. Comparing the fourth with the first quartile (for ttPeak comparing the first with the fourth quartile), risk estimates were: 7.8 (95% CI, 4.0‐15.0) for peak, 2.0 (95% CI, 1.2‐3.3) for ttPeak, 9.1 (95% CI, 4.4‐18.9) for ETP, and 11.5 (95% CI, 5.7‐23.3) for velocity index. Comparing the highest quartile of D‐dimer with the lowest, the risk was 7.7‐fold increased (95% CI, 4.0‐14.8). Furthermore, all factors also increased the risk of VT after dichotomizing at more extreme cutoff values. The risk of VT was further increased in the presence of multiple prothrombotic TG parameters and elevated D‐dimer level or in combination with prothrombotic mutations. Conclusions D‐dimer and TG parameters (except lag time) are associated with the risk of first VT in elderly population.

Background The preponderance of the evidence supports no association between traditional cardiovascular risk factors and venous thromboembolism (VTE), other than obesity. There are limited data in older people. Objectives To investigate whether cardiovascular risk factors (body mass index, smoking, alcohol intake, hypertension, and diabetes) are associated with the risk of VTE in elderly and to assess the combined effect between cardiovascular risk factors and genetic risk factors for VTE (factor V Leiden/prothrombin 20210A, positive family history of VTE, and non‐O blood group). Methods The Age and Thrombosis, Acquired and Genetic risk factors in the Elderly study is a multicenter case‐control study performed in Vermont, USA and Leiden, the Netherlands, comprising 401 cases with first VTE and 431 control subjects, all aged ≥70 years. To assess the risk of VTE, odds ratios (OR) with 95% confidence intervals (CIs) were calculated, adjusting for potential confounders. Results Both height and weight were positively associated with VTE risk: the ORs were 2.2 (95% CI, 1.2–3.9) and 1.5 (95% CI, 1.0–2.4) in the top quartile for height and weight separately. This risk was more pronounced for unprovoked VTE. Smoking, alcohol intake, and diabetes were not associated with VTE. Higher systolic and diastolic blood pressure and hypertension were associated with a decreased risk of VTE. In the presence of a genetic predisposition, height and weight further increased the risk of VTE. Conclusions In the elderly, height and weight are positively associated with the risk of VTE. With genetic predisposition, higher levels of height and weight further increase the risk of VTE.