Amyotrophic lateral sclerosis mortality in Italy, 1958 to 1987: a cross-sectional and cohort study.

We analyzed the mortality rates of amyotrophic lateral sclerosis (ALS) in Italy from 1958 to 1987. The overall mean annual mortality rate, adjusted to the 1981 Italian population, was 0.68/100,000 (95% confidence interval, 0.64 to 0.72); 0.86 for men; and 0.62 for women. During that period, mortality increased for both sexes: from 1958/1962 to 1983/1987, mortality increased by 60% for women and 24% for men. The slope for women was 0.07, and for men, 0.02. Moreover, the mortality rate increased in older age groups and was stable for subjects under 45 years old. There was no clear birth-cohort effect, but in any cohort the age-specific mortality rate increased with advancing age, with no decline for the oldest age. Based on these data, the increase of ALS mortality rates is probably due to the effect of changing methodologic and demographic variables and the decrease of mortality of some competing diseases, rather than a real rise of the risk in the whole population or in specific birth cohorts.