Febrile Seizures and School Performance.

Importance: Febrile seizures affect 2% to 5% of children and are associated with substantial parental distress and concerns about the child's long-term cognitive development. Objective: To examine the association between febrile seizures and school performance as measured by standardized tests. Design, Setting, and Participants: This is a nationwide register-based cohort study of children born in Denmark (1997-2009) who participated in the Danish National School Test Program from 2010 to 2019 (ages 7-17 years). Data were analyzed from March 2025 to June 2026. Exposure: Children with hospital contacts for febrile seizures identified through the Danish National Patient Register. Main Outcomes and Measures: The primary outcome was performance on norm-based standardized reading (grades 2, 4, 6, and 8) and mathematics (grades 3, 6, and 8) tests, scored as national percentiles (scale, 1-100). Adjusted differences in mean scores were estimated using linear regression. Results: Of 672 119 children (344 664 boys [51.3%]; 327 455 girls [48.7%]) participating in testing, 26 173 (3.9%) with a history of febrile seizures were identified. Combined test scores were marginally lower in children who experienced febrile seizures (108 265 tests; mean score, 54.7 points; 95% CI, 54.6 to 54.9 points) than in those who did not (2 684 629 tests; mean score, 55.8 points; 95% CI, 55.7 to 55.8 points), corresponding to an adjusted mean difference of -0.4 point (95% CI, -0.7 to -0.2 point). The difference was slightly more pronounced in girls (-0.7 point; 95% CI, -1.1 to -0.3 point) than in boys (-0.2 point; 95% CI, -0.5 to 0.2 point). School test performance declined with increasing number of febrile seizure-related hospital contacts, from -0.1 point (95% CI, -0.4 to 0.2 point) for those with 1 contact to -5.8 points (95% CI, -9.1 to -2.4 points) for those with 7 or more contacts. Epilepsy occurred more frequently in children with a history of febrile seizures (838 of 26 173 children [3.2%]) than in those without (5600 of 645 946 children [0.9%]), and was associated with substantially larger test score differences (children with febrile seizures and epilepsy vs children with neither, -7.2 points; 95% CI, -8.7 to -5.7 points). Test scores were also marginally lower in children with febrile seizures compared with their unaffected siblings (-0.6 point; 95% CI, -1.0 to -0.3 point). Conclusions and Relevance: In this cohort study of more than 26 000 children with febrile seizures, school performance was generally comparable to that of their peers, but a smaller subset (eg, children who had recurrent hospital contacts with febrile seizures or who developed epilepsy) were at risk of poorer academic outcomes and may benefit from additional educational support.