title: Prenatal and Perinatal Morbidity in Children with Tic Disorders: A Mainstream School-based Population Study in Central Spain.
abstract: BACKGROUND
  While current research suggests that genetic factors confer the greatest risk for the development of tic disorders, studies of environmental factors are relatively few, with a lack of consistent risk factors across studies. Our aim is to analyze the association of tic disorders with exposure to prenatal and perinatal morbidity.
  
  
  METHODS
  This was a nested case-control study design. Cases and controls were selected and identified from a mainstream, school-based sample. The diagnosis of tic disorders was assigned by a movement disorder neurologist using 'Diagnostic and statistical manual of mental disorders, 4th edition, text revision' criteria, and neuropsychiatric comorbidities were screened using the Spanish computerized version of the Diagnostic Interview Schedule for Children Predictive Scale. Information regarding the exposure to pre-perinatal risk factors was collected by a retrospective review of the birth certificates. Logistic regression analyses were then performed to test the association of tic disorders with pre-perinatal risk factors.
  
  
  RESULTS
  Out of 407 participants, complete pre-perinatal data were available in 153 children (64 with tics and 89 without tics). After adjusting for family history of tics, neonatal respiratory distress syndrome, body mass index, prenatal infection, and coexisting comorbid neuropsychiatric disturbances, tic disorders were associated with prenatal exposure to tobacco (odds ratio [OR] = 3.07, 95% confidence interval [CI] 1.24-7.60, p = 0.007), and cesarean section (OR = 5.78, 95% CI 1.60-20.91, p = 0.01).
  
  
  CONCLUSIONS
  This nested case-control study of children with tic disorders demonstrates higher adjusted odds for tics in children with exposure to cesarean delivery and maternal smoking. Longitudinal, population-based samples are required to confirm these results.
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Cubo
authors.affiliation: Pediatrics Department; Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Montesclaros
authors.initials: M
authors.lastname: Hortigüela
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Jorge-Roldan
authors.affiliation: Pediatrics Department; Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Selva Esther
authors.initials: SE
authors.lastname: Ciciliani
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lopez
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Leticia
authors.initials: L
authors.lastname: Velasco
authors.affiliation: Pediatrics Department; Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Sastre
authors.affiliation: Research Unit, Hospital Universitario Burgos, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Ausin
authors.affiliation: Research Unit, Hospital Universitario Burgos, Spain.
authors.forename: Vanesa
authors.initials: V
authors.lastname: Delgado
authors.affiliation: Research Unit, Hospital Universitario Burgos, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Saez
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: José Trejo
authors.initials: JT
authors.lastname: Gabriel-Galán
authors.affiliation: Neurology Department, Hospital Universitario Burgos, Burgos, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Macarrón
keywords: Tics; Tourette syndrome; cesarean delivery; cohorts; tobacco