Epidemiology of motor neuron disease in northern Sweden

Abstract

All cases of motor neuron disease (MND), encompassing amyotrophic lateral sclerosis (ALS), progressive bulbar paralysis (PBP) and progressive spinal muscular atrophy (PSMA), in northern Sweden, diagnosed between 1969-1980 have been analysed. 128 cases were found, corresponding to an average annual incidence rate of 1.67 per 100,000. The prevalence on December 31, 1980 was 4.8 per 100,000. Age-specific incidence rates were higher in the high age groups with a maximum at 60-64 years for males, at 70-74 years for females and at 65-69 years for the sexes combined. The median age at onset was 61 years. Clustering was not found in mining districts and overrepresentation of miners and stone treaters was not observed. Minor differences in incidence rates, as measured by the standardized morbidity ratio, SMR, were found between the inland, coastal and mountain areas. The median survival time after onset of disease was 32 months for ALS, 30 months for PBP and 70 months for PSMA. The combined survival rate for all MND cases was 28% after 5 years and 15% after 10 years. The male to female ratio was 1.1:1, and 4.7% were familial cases.

Prognosis and epidemiology of amyotrophic lateral sclerosis

“…The average age at diagnosis fell within the norms of population-based studies of 57 to 68. 1,4,5,7,9,15,16 Although several authors report increased survival in referral cohorts compared to population-based cohorts, 1,13 the median survival of 15.8 months in our registry is similar to that reported for other series. 9 The concern for bias generated by the exclusion of long-term survivors was partially addressed by re-analysis of the cohort after exclusion of those patients surviving .7 years after onset.…”

Survival of Patients with Amyotrophic Lateral Sclerosis in a Population-Based Registry

“…However, the clinical spectrum of the disease is wide and tends to refl ect the heterogeneity of the symptoms at onset and the variability of its course. Information on the prognosis of ALS has mostly been obtained from population-based studies or large clinical series [1,[4][5][6][7][8][9][10][11][12][13][14][15][16] . In these studies, survival of ALS patients varied signifi cantly depending on the methods used for case ascertainment, the different diagnostic criteria, and the small numbers of cases surviving beyond the fi rst few years.…”

127th ENMC International Workshop: Implementation of a European Registry of ALS Naarden, The Netherlands, 8–10 October 2004

“…Amyotrophic lateral sclerosis (ALS) is a rare neurological condition (overall annual incidence rate in Europe 0.4-2.5 per 100,000) [1][2][3][4][5][6][7] with severe prognosis and death within 3-5 years from diagnosis [8][9][10]. Several community studies have been performed to study the incidence and characteristics of ALS in Europe.…”

“…Several community studies have been performed to study the incidence and characteristics of ALS in Europe. These include surveys from well-defined populations [4][5][6][7] and studies from population-based regional [3] and national registries [1,2]. Although these registries provide fairly high and homogeneous incidence rates, they have insufficient power to study risk factors with low exposure levels, because of the small sample size.…”