A prospective study of smoking, caffeine, and alcohol as risk factors for seizures or epilepsy in young adult women: data from the Nurses' Health Study II.

PURPOSE: Seizures and epilepsy are associated with significant disability and substantial treatment costs, yet little is known about primary prevention. We prospectively examined the association of cigarette smoking, caffeine use, and alcohol intake with risk of seizure or epilepsy among women, aged 25-42 years, in the Nurses' Health Study II. METHODS: Participants provided dietary and cigarette smoking information on multiple questionnaires beginning in 1989. Among 116,363 women at-risk for incident seizure or epilepsy, we confirmed 95 cases of seizure and 151 cases of epilepsy occurring from 1989-2005 using information from a detailed supplementary questionnaire and medical records. Multivariable-adjusted relative risks (RRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression. RESULTS: Compared with never smoking, current cigarette smoking was associated with an increased risk of seizure (RR 2.60, 95% CI 1.53-4.42), after adjustment for stroke and other potential confounding factors. Past smoking was not associated with risk of seizure, but was associated with modestly increased risk of epilepsy (RR 1.46, 95% CI 1.01-2.12). Long-term caffeine and moderate alcohol intake were not associated with seizure or epilepsy. DISCUSSION: Cigarette smoking may be associated with increased risk of seizure. More prospective studies are needed to investigate potential factors to ultimately prevent the development of seizures or epilepsy.