Amyotrophic lateral sclerosis in Sardinia (Italy): epidemiologic features from 1957 to 2000

To evaluate epidemiological variables of amyotrophic lateral sclerosis (ALS) in Sardinia (Italy) in the 1991-2000 periods and compare them with the preceding decades.Survey, critical reappraisal or clinical re-evaluation of all ALS cases with onset in the decade 1991-2000; calculation of crude and age-adjusted incidence, duration of disease, survival rates and the latency between onset of symptoms and diagnosis.A significant increase in the mean annual incidence was observed in comparison with the values found in the two previous decades, 1971-1980 and 1981-1990. The distribution of the disease in various areas of the island was found to be not at all homogeneous. No significant modifications of the duration of the disease and survival rates were observed.The role of particular exogenous factors, albeit still unclear, can be invoked.