Motor neuron disease in the province of Ferrara, Italy, in 1964-1982.

We carried out an intensive incidence, prevalence, and mortality survey of motor neuron disease (MND) in the province of Ferrara, northern Italy. Based on 72 patients, the mean incidence per year for the period 1964 through 1982 was 0.98 cases per 100,000. On December 31, 1981, the prevalence rate was 3.95 per 100,000. In the 19-year period the average mortality rate was 0.83 per 100,000 per year. The disease was more common in men, in individuals aged 50 to 70 years, and in residents in rural areas engaged in agricultural work. A retrospective case-control study, confirming a significantly higher frequency of MND in farmers and persons living in rural areas, revealed that the disease was more common in the lower social classes to which most unskilled and heavy laborers belong. In addition, a significantly increased risk for MND was found in patients with previous histories of trauma, but confounding variables may account for this association.