Prevalence of Epilepsy in Rural Iceland: A Population‐Based Study

Abstract

Summary:Purpose: To determine the prevalence of epilepsy (recurrent unprovoked seizures) in the population of rural Iceland.Methods: Review of records of primary-care facilities for the population of rural Iceland supplemented by review of referrals to electroencephalographic facilities and neurologic specialists to identify all individuals with unprovoked seizures or receiving treatment for epilepsy in the calendar year 1993.Results: Crude prevalence was 4.8 per 1,000 and was 4.8/ 1,000 after age adjustment to the 1970 United States population. Age-adjusted prevalence was higher in male (5.1) than in female subjects (4.4) and increased with advancing age. Sixtytwo percent of prevalence cases were of unknown cause. Sixtythree percent of cases had major motor seizures without aura or generalized epileptiform pattern on EEG. Sixty-four percent of patients had had seizures in the year of observation. Seizure control was inversely correlated with number of medications. Ten percent of the prevalence group was taking no medication, although the frequency of seizures was high in this medicationfree group.Conclusions: Prevalence of epilepsy in rural Iceland is consistent with that reported in recent studies in other developed countries. The data provide insights into the approaches of treatment and use of specialized diagnostic testing in the country. The prevalence is similar to that in other European countries but lower than that reported from rural areas in Latin America. Key Words: Epidemiology-Epilepsy-SeizuresPrevalence-Iceland.The prevalence of epilepsy has been studied more frequently than the incidence, but results vary considerably. This difference in reported prevalence of epilepsy is due to differences in both definition and methodology (1). Prevalence studies include both recently diagnosed cases that are likely to remit and the more chronic cases, which are unlikely to resolve spontaneously. Prevalence studies provide insights into patterns of health care and are of value for the determination of health-care needs. Prevalence studies also can provide information for hypothesis generation in epilepsy research.We conducted a retrospective study in a well-defined population in rural Iceland to determine the prevalence of active epilepsy on December 31, 1993. METHODSIceland is an island with a total population of 262,000 in 1993. Approximately 110,000 live in rural Iceland.Accepted April 28, 1999.Addresa correspondence and reprint requests to Dr. E. Olafsson at Department of Neurology, National University Hospital (Landspitalinn), I01 Reykjavik, Iceland. E-mail eliasol@rsp.is Health care for the rural population is provided by welldefined health-care districts generally comprising one or two small towns and sparsely populated surrounding countryside. There are small hospitals in some districts. Government-run local health-care centers provide all medical care. Our study population comprises 37 of 42 medical districts in rural Iceland with a mean population of 89,656 on December 1, 1993. Case finding was done t...

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