Immunogenetic heterogeneity and associated autoimmune disorders in myasthenia gravis: a population-based survey in Ferrara, northern Italy

INTRODUCTION: We planned a descriptive study on the incidence of intracranial gliomas spanning a 16-year period (1976-1991) in the Local Health Service 31 of Ferrara, Northern Italy. MATERIAL AND METHODS: We used a complete enumeration approach by reviewing all the possible sources of case collection available in the study area. RESULTS: The mean annual incidence rate was 5.8 new cases per 100,000 population (6.96 for men and 4.78 for women; p < 0.05), resulting in 4.7 per 100,000 when directly adjusted to the Italian population. The age-specific incidences showed a small peak in childhood, an increase with age, reaching a maximum in the age group 60 to 64 and then a decline in the elderly. This pattern is similar for both sexes. The adjusted rates increased from 3.94 per 100,000 population in the first five-year period to 5.6 per 100,000 in the third (a nonsignificant difference). The distribution of cases within the study area was substantially uniform. CONCLUSION: The incidence rates of Ferrara fell into the middle-high values so far reported and confirmed the male preponderance found in previous studies. The age-related pattern is similar to that observed, with few exceptions, in other surveys. Like other authors we did not find a significant temporal trend, although the incidence rates tended to increase with time. The data encourage further, wider epidemiological studies of a prospective nature.