Febrile convulsions increase risk of Tourette syndrome

PURPOSE Febrile convulsion (FC) and Tourette syndrome (TS) are both common neurological disorders in infants and children. Both disorders share clinical similarities, such as paroxysmal symptoms with normal neurodevelopment and expected remission over time. This population-based study investigated the association between FC with TS during childhood neurodevelopment. METHOD We used the Taiwan National Health Insurance Research Database to conduct a retrospective cohort analysis on 1586 FC patients. A reference cohort of 6344 non-FC patients, matched for age, sex, urbanization level, parental occupation, and index year, was used for comparison. The risk of the occurrence of TS in FC patients was assessed using a Cox proportional hazard regression model. RESULTS The overall incidence of TS was higher in the FC cohort than in the non-FC cohort (28.5 vs 13.9 per 10,000 person-years; adjusted hazard ratio=1.91, 95% confidence interval=1.32-2.75). The associated risk factors for FC patients to develop TS were boys, children living in rural areas, and children whose parents held blue-collar positions. Moreover, the risk of TS in FC patients rose from 0.89 to 16.0 (trend test P<0.0001) when the frequency of FC-related medical visits increased from 1 to 2 times to more than 4 times. The adjusted hazard ratio for TS in related to FC-related medical visits was 1.02 (95% CI=1.02-1.03) per one frequency increment. CONCLUSION FC may increase the risk of subsequent TS occurrence in children. Children who had frequent medical visits for FC were particularly vulnerable.