Autism spectrum disorder prevalence and associated sociodemographic factors in the school population: EPINED study
Authors: Morales Hidalgo Paula , Voltas Moreso Núria , Canals Sans Josefa 
Published: April 2021

The autism spectrum disorder prevalence data for southern Europe seem to be lower than international reports. The objective of the Neurodevelopmental Disorders Epidemiological Research Project was to estimate the prevalence of autism spectrum disorder in a representative school sample of Tarragona, Spain. Screening was performed through parents ( N = 3727) and teachers ( N = 6894), and 781 children were individually assessed. The overall estimated prevalence was 1.53% (1.78% in preschoolers; 1.30% in primary school children), being significantly higher than the 0.83% previously registered (0.92% and 0.74%, respectively). Respectively, 4.23% and 2.85% of the children showed subclinical autism spectrum disorder. Girls showed a significantly lower prevalence in all the conditions. Severity profiles were distributed as 46% mild, 47% moderate and 7% severe. A high ratio of males (90%) and children from Eastern Europe (16%) was found among severe autism spectrum disorder. Language therapy (51%) and psychological (65%) and educational supports (65%) were given to children with autism spectrum disorder. Pharmacological treatment was only found among school-aged children (37.5%). Public schools provided more educational support (72%) than private schools (36%). The heterogeneity of autism spectrum disorder makes it difficult to determine specific associated sociodemographic factors. The results confirmed a high prevalence of autism spectrum disorder in this province, suggesting a current under-diagnosis by public health services. Lay abstract An increase in the prevalence of autism spectrum disorder has been reported around the world over the past decade. However, the prevalence data for southern Europe seem to be lower than international reports and notable methodological differences have been reported among studies. The objective of the Neurodevelopmental Disorders Epidemiological Research Project was to estimate the prevalence of autism spectrum disorder in a representative school sample of the province of Tarragona, Spain. The study included a screening procedure through parents ( N = 3727) and teachers ( N = 6894), and an individual assessment of children at risk and a comparison group ( N = 781). The overall estimated prevalence in our sample was 1.53%, being significantly higher than the 0.83% previously registered diagnoses. A total of 3.31% of the children presented subclinical characteristics of autism spectrum disorder. Girls showed a significantly lower estimated prevalence in all the conditions. Severity profiles were distributed as 46% mild, 47% moderate and 7% severe. Psychological support (65%), educational support (65%) and language therapy (51%) were given to children with autism spectrum disorder. Pharmacological treatment was only found among school-aged children (37.5%). Public schools provided more educational supports (72%) than private schools (36%). The heterogeneity of autism spectrum disorder makes it difficult to determine specific associated sociodemographic factors. The results confirmed a high prevalence of autism spectrum disorder in the province, suggesting a current under-diagnosis in public health services. In view of the results, it is important to promote early diagnosis and intervention, especially in particular groups such as girls, children with intellectual disabilities and children from immigrant families.