Epilepsy in immigrants and Swedish-born: A cohort study of all adults 18 years of age and older in Sweden

Purpose: We aimed to study the association between country of birth and incident epilepsy in several immigrant groups using Swedish-born individuals as referents. Method: The study population included all adults aged 18 years and older in Sweden, living and deceased, 6,690,598 in the first-generation and 6,683,125 in the second-generation sub-study. Epilepsy was defined as having at least one registered diagnosis of epilepsy in the National Patient Register. The incidence of epilepsy in different immigrant groups, using Swedish-born as referents, was assessed by Cox regression, expressed as hazard ratios (HRs) and 95 % confidence intervals (CI). The models were stratified by sex and adjusted for age, geographical residence in Sweden, educational level, marital status, and neighbourhood socioeconomic status. Results: In the first-generation sub-study, totally 76,541 individuals had at least one registered diagnosis of epilepsy (1.14 % in total; men 1.22 % and women 1.07 %), and in the second-generation study 72,545 (1.09 %; men 1.18 % and women 0.99 %). After adjusting for confounders, in first-generation immigrants compared to their Swedish-born counterparts the incidence was somewhat lower among both men (HR 0.92, 0.90-0.96) and women (HR 0.93, 0.90-0.96), and in the second-generation immigrants among women (HR 0.95, 0.92-0.99) but not men (HR 0.99; 0.96–1.02). Among immigrant groups, a higher incidence of epilepsy was observed among first-generation women from Africa and Iraq, and second-generation men and women from Bosnia, and women from Finland. Conclusions: Risk of epilepsy was lower in immigrants in general compared to the Swedish-born population; but with higher incidence in some specific groups.