Objective: To identify risk factors predictive of a first febrile seizure.
Design: Case-control study.
Setting: Regional referral pediatric hospital emergency department.
Patients: Seventy-five patients aged 6 months to 4 years presenting with a first febrile seizure were age-matched to two febrile and two afebrile noninfectious controls who had never had a seizure.
Methods: Telephone interview of parents.
Main outcome measures: Risk factors assessed included family history of febrile or afebrile seizures, neurodevelopmental abnormality, and child-care arrangement. Analysis was done by matched case-control and logistic regression.
Results: Factors associated with a significant increase in risk of a first febrile seizure were febrile seizures in first-degree relative (odds ratio [OR], 4.5) or second-degree relative (OR, 3.5); neonatal discharge at 28 days or later (OR, 5.6); parental report of "slow" development (OR, 4.9); and day-care attendance (OR, 3.1). For children with two risk factors (an estimated 3% of the population), the risk of developing febrile seizures is approximately 28% (assuming a population incidence of febrile seizures of 4%).