Results of Florida's Amyotrophic Lateral Sclerosis Surveillance Project, 2009-2011

Studies to determine the incidence and prevalence of amyotrophic lateral sclerosis (ALS) in defined geographic areas in the USA are needed. The Florida Department of Health received funding from the federal Agency for Toxic Substances and Disease Registry to implement a state-wide ALS Surveillance Project. The objectives of the project were to describe the demographic characteristics of ALS cases and to calculate the incidence and prevalence of ALS in Florida.

All neurologists were asked to submit case reports for persons with ALS diagnosed and/or under their care during 1 January 2009 through 31 December 2011. A medical record verification form and an electromyogram (EMG) report were requested for a sample of cases and reviewed by an independent consulting neurologist to confirm ALS diagnosis. Death data were used to aid with case report collection.

Demographics, relevant history and clinical characteristics, El Escorial classifications, time from symptom onset to diagnosis, crude annual incidence rates and 2009 period prevalence are presented.

The 1450 reported ALS cases were more likely to be older, male, white and non-Hispanic. Slightly more than 4% of cases were reported as also having dementia, and 4.8% were reported to have an immediate family member diagnosed with ALS. Incidence rates ranged from 1.7 to 1.9 per 100,000 person-years during the project period and the 2009 period prevalence was 4.0 per 100,000 persons.

Project findings are generally consistent with findings of population-based studies in Europe, as well as geographically limited studies in the USA. Our findings add to the growing body of epidemiological literature about ALS in the USA. Future epidemiological studies in the USA should focus on identifying cases from minority groups and those that may have limited access to healthcare, and should consider conducting capture-recapture analysis to assess case ascertainment.