Further studies on multiple sclerosis in iceland

A third survey of multiple sclerosis (MS) in Iceland has been performed covering the decade 1956–1965 and the patients have been followed-up to 1973. The same diagnostic criteria have been used as in the second survey (1946–1955). During the period 37 new patients were encountered and, of these, 34 were classified as definitely or probably suffering from MS. The whole material, i.e. including MS-patients alive or dead at some time during 1946–1965, now amounts to 129 definite and probable cases of which 50 are males and 79 are females, and 13 possible cases of which 7 are males and 6 are females. The possible cases are not included in the statistical figures in this abstract. The mean age at onset was higher in this survey than in the second survey, i.e. 32 years as compared to 27 before. In 1960 the prevalence rate was 42.8 100,000 for males, 62.1 for females and 52.4 for both sexes, and in 1965 the figures were 44.0, 60.7 and 52.3 respectively. The age-specific prevalence rate was highest in the age groups 30–39 and 40–49, figures similar to those obtained in the second survey. The incidence rate during the survey period 1956–1965 was 1.9 100,000 per annum. In the previous decade it was somewhat higher at 3.1 100,000 per annum. There were 9 families containing more than 1 case and the familial incidence was 7.0%. There was some evidence of accumulation of cases in Eastern Iceland and of a local accumulation in Southern Iceland.