INCIDENCE OF AMYOTROPHIC-LATERAL-SCLEROSIS IN 3 COUNTIES IN WESTERN WASHINGTON-STATE

We conducted a population-based study of amyotrophic lateral sclerosis (ALS) in King, Pierce, and Snohomish counties in western Washington s tate. Between April 1, 1990 and March 31, 1995, neurologists diagnosed 235 patients with ALS, including 127 men (54%) and 108 women (46%). T he incidence rate, age-adjusted to the 1990 total U.S. population, was higher for men at 2.1 per 100,000 per year (95% CI, 1.3 to 2.9) than for women at 1.9 (95% CI, 1.1, 2.7) and increased with age for both me n and women. These incidence rates are consistent with other studies f rom northern latitudes.