Increased Prevalence of Tic Disorders in Premature Children: A Prospective Study from Northern Italy

Environmental risk factors for tic disorders are not yet fully understood. Both prenatal and perinatal factors, especially prematurity and maternal smoking in pregnancy, have been suggested as predictors for the development of tic disorders in the offspring. We assessed possible associations with prenatal and perinatal factors using comprehensive clinical data of 406 premature and very/extremely low weight newborns admitted to a single Neonatal Intensive Care Unit between 2008 and 2012. Of these, 264 were followed up after 8–11 years to evaluate the possible development of a tic disorder via a two-stage process involving a telephone interview with their parents and a face-to-face assessment. We found that 6.8% of children born premature with birth weight lower than 1500 g developed a tic disorder during childhood (before the age of 8–11 years). The prevalence of tic disorders in the offspring of mothers who smoked more than five cigarettes per day during pregnancy was 20.0%, compared to 7.6% in nonsmoking mothers. Our findings support the hypothesis that premature children have an increased risk of developing a tic disorder and prompt further research into the possible contributing role of modifiable risk factors such as maternal smoking during pregnancy.