The epidemiology of ALS in Modena, Italy

To determine the incidence, prevalence, and mortality rates of ALS in the province of Modena, Northern Italy, from 1990 through 1999.

A retrospective epidemiologic study was conducted, ascertaining cases from all neurologic centers and hospitals of the province, death certificates, and the Italian ALS Association, section of Modena. All clinical records were reviewed, and only patients fulfilling the El Escorial revised diagnostic criteria were included.

During the period considered (1990 to 1999), 143 residents (67 men and 76 women) entered the study. The average annual incidence was 2.16 per 100,000, with a peak in the age class of 75 to 79 years. Mean prevalence rate was 4.02 per 100,000, and mean mortality rate was 1.69 per 100,000. The incidence rate remained constant over time, whereas the prevalence and mortality rates increased owing to a rise in survival time (ALS mean duration was 17.38 months in 1990, 43.18 months in 1999). In the mountainous areas, where agricultural work is more common, the incidence, prevalence, and mortality rates were higher than in urban areas and the disease onset occurred 10 years later. Of the risk factors examined, only agricultural work and rural residence were significant.

The incidence, prevalence, and mortality rates agree with those in recent Italian surveys and with most international studies, but the distribution of cases varied with higher rates in mountainous areas. Further prospective studies are required.