title: Febrile convulsions increase risk of Tourette syndrome.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  FC may increase the risk of subsequent TS occurrence in children. Children who had frequent medical visits for FC were particularly vulnerable.
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Tu
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan; Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Cheng-Li
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chih-Hao
authors.initials: CH
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chao-Chin
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Management Office for Health Data, China Medical University Hospital, Taichung, Taiwan; Department of Public Health, China Medical University, Taichung, Taiwan.
authors.forename: Fung-Chang
authors.initials: FC
authors.lastname: Sung
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan; Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan. Electronic address: d10040@mail.cmuh.org.tw.
authors.forename: Chia-Huang
authors.initials: CH
authors.lastname: Kao
mesh_terms: D015897:Comorbidity; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D053208:Kaplan-Meier Estimate; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D003294:Seizures, Febrile / Q000150:complications / Q000453:epidemiology*; D012737:Sex Factors; D012923:Social Class; D013624:Taiwan / Q000453:epidemiology; D005879:Tourette Syndrome / Q000453:epidemiology* / Q000209:etiology; D014505:Urban Population / Q000706:statistics & numerical data
keywords: Children; Febrile convulsions (FC); National Health Insurance Research Database (NHIRD); Tourette syndrome (TS)