Environmental Factors in Autism Spectrum Disorder: A Case Control Study from Tunisia
Objectives: to investigate environmental factors that may interfere with ASD physiopathology
A case-control study was conducted from July 2014 to August 2015, at the Child and Adolescent Psychiatry Unit at the University Hospital of Monastir. We included all outpatients diagnosed with ASD seen during their routine follow-up. A control group was chosen randomly in 4 different kindergarten of the region of Monastir. Each group included 200 children, with a sex ratio M/F of 4.2 and a mean age of 3.3 years. ASD was diagnosed according to DSM-IV criteria (including autistic disorder, Asperger’s disorder and PDD-NOS) by certified Child and Adolescent Psychiatrists and the Childhood Autism Rating Scale (CARS). We excluded children with neurological or genetic comorbidities. In the control group, we excluded children with abnormal m-CHAT or abnormal psycho-emotional development.
Environmental factors were assessed by a structured questionnaire eliciting obstetric, family and social factors. One-way ANOVA test was used for statistical analysis.
Statistically significant differences were found for the use of ovulation induction by the mother, and for the proportion of first borns, both factors being more prevalent in ASD group. Partner violence and use of physical punishment were also significantly more reported in ASD group.
No statistical difference was found for the following factors:
- Age of the mother or the father,
- In vitro fertilization and twin pregnancy,
- Mother depression during pregnancy and the use of antidepressant medication during pregnancy
- Work of the mother and duration of maternal leave
- Breastfeeding duration
- Presence of multiple attachment figures
Some environmental factors may be associated with autism in a way that needs to be further assessed.