title: An epidemic-like cluster of motor neuron disease in a Swedish county during the period 1973-1984.
abstract: We have tried to find all cases of motor neuron disease (MND) with onset during the study period 1961-1990 in the county of Skaraborg, Sweden, and in this retrospective study we have identified 168 cases, 107 men and 61 women. Fifty percent of them were alive 2 years after onset. The number of MND cases in consecutive 5-year intervals during the study period was shown to be statistically significantly elevated for males in the period 1981-1985 (Knox test disjoint procedure, p = 0.02). During the period 1973-1984, 70 males had onset of MND, corresponding to an average annual incidence of 4 per 100,000 person-years. This epidemic-like cluster was compared to the MND morbidity in a neighbouring county and was shown to be statistically significantly elevated even when the p value was adjusted for multiple comparisons. Agricultural work was significantly more common among the cases compared to the rest of the population.
authors.affiliation: Department of Occupational Medicine, Orebro Medical Center Hospital, Sweden.
authors.forename: L G
authors.initials: LG
authors.lastname: Gunnarsson
authors.forename: P E
authors.initials: PE
authors.lastname: Lygner
authors.forename: J
authors.initials: J
authors.lastname: Veiga-Cabo
authors.forename: J
authors.initials: J
authors.lastname: de Pedro-Cuesta
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000382:Agricultural Workers' Diseases / Q000453:epidemiology / Q000209:etiology; D016001:Confidence Intervals; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D016472:Motor Neuron Disease / Q000453:epidemiology* / Q000209:etiology; D012189:Retrospective Studies; D017678:Sex Distribution; D013029:Space-Time Clustering; D013548:Sweden / Q000453:epidemiology