Autism Spectrum Disorders in Catalonia, Spain: A New Population-Based Case-Cohort Study to Investigate Environmental Factors

摘要

Background: Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by impaired social interaction, deficits in social communication and restricted, repetitive, and stereotyped behaviors. Studies conducted in Northern Europe and United States have estimated an ASD prevalence of 0.61% and 0.67% respectively. In Spain there is only one small epidemiological study conducted in the Canary Islands in 2012 that shown a prevalenceof 0.61%. The aim of this study is to estimate the ASD prevalence in 2016 and the cumulative yearly incidence between 2010 and 2016 in children in Catalonia, Spain. Methods: We set up a population-based cohort that included all children between 0 and 18 years of age insured in the Catalan Health System between 2010 and 2016. We identified all ASD cases diagnosed between 2010 and 2016 from the registry of the Catalan Health System (named Minimum Basic Data Set) by the ICD-9 codes 299.0, 299.1, 299.8, and 299.9. We estimated the ASD prevalence for 2016 and the cumulative yearly incidence between 2010 and 2016 with the 95% confidence intervals based on Poisson error structure. Results: We estimated an ASD prevalence of 0,93% (95% CI 0.88, 0.98) in children from 0 to 18 years of age in Catalonia in 2016. The ASD prevalence was 0.76% (95% CI 0.67, 0.84) in boys and 0.17% (95% CI 0.10, 0.24) in girls, with a sex ratio 4.44-fold higher in boys than girls.The ASD incidence increased from 0.06% (95% CI 0.01, 0.10) in 2010 to 0.18% (95% CI 0.10, 0.26) in 2016. Conclusions: The estimated ASD prevalence of 0.93% was higher than the average estimate reported in previous studies in Europe or United States. The prevalence was higher in boys than girls, with a sex ratio similar to previous studies. We also observed an increasing temporal trend of the ASD incidence in recent years. This new case-cohort study on ASD will allow investigating the role of environmental factors in the origins of ASD.