Wegener’s Granulomatosis and Microscopic Polyarteritis Case Control Study in Western Montana

Investigators: Helen Emery, M.D., Andrew Zeft, M.D. and Peggy Schlesinger, M.D.

Location: University of Washington, Children's Hospital and Regional Medical Center, Section of Rheumatology, Seattle, Washington

Timeline: August 1, 2004 – July 30, 2005

Abstract:  Etiologic factors for Wegener’s Granulomatosis (WG) and Microscopic Polyarteritis (MPA) have not been identified, although it is possible that specific environmental exposures may trigger disease onset in a susceptible host. Previous studies have shown an increased risk of these disorders in patients with certain environmental exposures, the clearest association being with occupational silica.
In the last ten years, the Montana rheumatology community has observed an increased incidence and case clustering of both WGA and MPA in certain counties of western Montana. The mining industry and areas with known high heavy metal concentrations make this region unique.

Specific aim:  To evaluate the relative risk of Wegener’s Granulomatosis and Microscopic Polyarteritis in a defined population in Western Montana, focusing on residential and occupational exposure to silica, heavy metals, and pesticides.

We will identify and characterize all WG and MPA cases in western Montana onset from January 1993 to June 2004 by case report from Montana rheumatologists, pulmonologists, nephrologists, and otolaryngology physicians. Using hospital records, we will identify two controls matched by age, gender, race, and distance to the hospital of index WG or MPA cases. We will interview index and control cases for residential and occupational exposures to silica, heavy metals, and pesticides.