Systemic Vasculitis: An Epidemiological Perspective

The aetiology of the systemic vasculitides is unknown, clues to the causation may be revealed by their epidemiology. The epidemiology of vasculitis poses considerable challenges to epidemiologists. These challenges include the difficulty of defining a case with a lack of clear distinction between the different disorders, case capture and case ascertainment. The vasculitides are generally rare and therefore a large population is required to accurately determine incidence and prevalence, and this poses questions of feasibility. Nonetheless, despite these difficulties a considerable body of data on the epidemiology of the vasculitides has developed over the past 30 years with interesting age, geographic and ethnic tropisms gradually being revealed. Most of the data comes from Caucasian populations of European descent. In this article we describe the epidemiology of systemic vasculitis focusing on possible risk factors such as age, ethnicity, infection, drugs and other possible environmental agents.