Using capture-recapture method to estimate multiple sclerosis prevalence in areas around Spokane, Washington

Multiple sclerosis (MS) is a chronic autoimmune disease with suspected environmental contributors, including exposure to ionizing radiation. To investigate community concerns about high MS prevalence near the former Hanford nuclear site, this study estimated MS prevalence in twelve counties surrounding Spokane, Washington, from 1998 to 2003. Medical records from two major MS care systems identified 1,088 unique cases; capture‑recapture analysis estimated 1,626 total cases. Crude MS prevalence was 196.8 per 100,000 adults, with a higher estimate of 294.1 per 100,000 using capture‑recapture methods. County‑level analyses showed an association between MS prevalence and per‑capita income. Findings confirm elevated MS prevalence in the region and highlight the need for expanded diagnostic resources, improved access to care, and further investigation incorporating additional data sources.