EPIDEMIOLOGIC FEATURES OF GUILLAIN-BARRE-SYNDROME IN SWEDEN, 1978-93

Objectives-To describe the incidence of Guillain-Barre syndrome in Swe den during the period 1978-93 and its temporal and geographical variat ions. Methods-Stratified and Poisson regression analyses and tests for detection of small epidemics were applied to population based hospita l discharge data from 2257 incident cases of Guillain-Barre syndrome i n Sweden during the study period. Results-The incidence of Guillain-Ba rre syndrome was (1) 1.77 per 100 000 person-years when age adjusted t o the European population; (2) higher in males; and (3) stable across time, although occasional increases of annual incidence rates were fou nd-namely, in 1978 (relative risk (RR) 1.30 (95% CI 1.10-1.54)), and i n 1983 (RR 1.24 (95% CI 1.06-1.40)). The incidence increased with age and was bimodal, with peaks at 20-24 and 70-74 years. There was a mode rate but significant seasonality with a peak in August, particularly a mong the young age groups. The age adjusted incidence by county varied from 1.11 to 2.57 per 100 000 person-years. Neither temporal nor spat ial clustering was significant, except during the period July-Septembe r in 1983 at ages below 40 years. Conclusions-The incidence of Guillai n-Barre syndrome in Sweden during the period 1978-93 had a magnitude s imilar to those described in other surveys, a bimodal distribution by age, and modest geographical and temporal variations with significantl y high rates in 1978 and 1983 and in autumn. Minor outbreaks might hav e passed unnoticed up to the present. Whereas reported drug induced ca ses of Guillain-Barre syndrome may in part explain the high incidence in 1983, the cause of the aberrant incidence in 1978 remains unknown. Epidemiological surveillance of Guillain-Barre syndrome in Sweden migh t have been useful.