Epidemiology of Wegener's granulomatosis: Lessons from descriptive studies and analyses of genetic and environmental risk determinants.

During the past 15 years, the epidemiology of Wegener's granulomatosis (WG) has become better understood. Descriptive epidemiological studies carried out primarily in European countries estimate a prevalence of WG ranging from 24 to 157 per million and annual incidence rates from 3 to 14 per million. These studies suggest a North-South declining gradient in disease risk in the Northern Hemisphere and an increase in incidence over time, although the latter is likely largely due to improved diagnostic ascertainment. Data also indicate the presence of potential secular and seasonal variations in WG incidence and a decreasing disease risk among non-Caucasians. Furthermore, analytic epidemiological studies have pointed out putative genetic and non-genetic risk factors for WG. Genetic investigations have identified various candidate genes, with alpha1-antitrypsin deficiency being the most consistently reported genetic susceptibility factor to date. Even though much less research has been devoted to environmental risk factors, evidence has grown for a possible relationship between WG and occupational exposure to crystalline silica. Thus far, data support the concept of WG as a multifactorial disease in which genetic and environmental determinants are involved but a major gap in understanding persists regarding the extent to which both factors contribute to its development. This and many other questions remain to be answered by future structured epidemiological research. This review focuses on the current knowledge of descriptive epidemiology and genetic and environmental factors associated with WG.