BACKGROUND: Arterial age can be estimated from equations relating arterial stiffness to age and blood pressure in large cohorts. We investigated whether estimated arterial age (eAA) was elevated in patients with the metabolic syndrome and/or known cardiovascular disease (CVD), which factors were associated with eAA and whether eAA added prognostic information. METHODS: In 1993, 2366 study participants, 41, 51, 61, and 71 years old, had traditional cardiovascular risk factors and carotid-femoral pulse wave velocity (cfPWV) measured. Risk groups were identified based on known CVD and components of metabolic syndrome, Systematic COronary Risk Evaluation, or Framingham risk score. From age, mean blood pressure, and cfPWV, eAA and estimated cfPWV (ePWV) were calculated. In 2006, the combined cardiovascular endpoint (CEP) of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for ischemic heart disease was registered. RESULTS: cfPWV and ePWV increased with ageing and cardiovascular risk (all P