Prevalence of Autism Spectrum Disorders in Qatar: A National Epidemiological Survey
Objectives: To generate a first estimate of the prevalence of ASD among school age children in Qatar, using a whole population-based approach; and to evaluate correlates of ASD in a large representative sample of cases.
Methods: We surveyed the population of children age 5 to 12 (N=176,960) residing in Qatar in 2015. Children of Qatari and resident families were included. Case ascertainment relied on two complementary approaches. First, eligible children attending medical/special needs centers and schools providing diagnostic and treatment services for children with ASD were screened. Records of eligible children were abstracted and supplemented by parental interviews. Second, we performed a two-stage survey for regular primary school children. Following a screening with the locally validated version of the Social Communication Questionnaire (SCQ), random samples of screen positive and negative children were further evaluated to determine ASD case status. Prevalence among children age 6 to 11 was estimated after taking into account different sampling fractions and participation rates at each survey phase. Medical, developmental, educational and behavioral data were collected on all ASD cases and analyzed to describe trajectories of ASD children.
Results: 1,393 children already diagnosed with ASD were identified through the medical and educational centers. Among 9,074 participants in the school survey, 773 (8.5%) were screened positive. In the diagnostic confirmation phase, 163 screen positive and 760 screen negative children were evaluated; 17 were confirmed to have ASD, including 5 children newly diagnosed. Combining data from the two samples, prevalence was estimated to be: 1.14% (95% CI: 0.89-1.46) among 6 to 11 year olds, 1.81% (95% CI: 1.41-2.31) among boys, 0.44% (95% CI: 0.35-0.57) among girls, and 1.52% (95% CI: 1.19-1.94) among 8 year olds. Analysis of detailed information on 844 ASD cases (mean age: 7.2 years; 81% male) showed ASD recurrence in 5.9% full siblings and 9.65% relatives. Most children had experienced language delay (75.1% for words; 91.4% for phrase speech), and 19.4% reported developmental regression. At the time of the survey, a substantial minority of subjects had persisting deficits in expressive language (19.4%), peer interactions (14.0%), behavioral problems (ADHD: 30.2%; anxiety: 11.0%) and 20.5% required behavioral support at school. About 25% of the sample scored high on a composite indicator of severity. In multivariate logistic regression, ASD severity was associated with parental consanguinity, gestational diabetes, delay in walking, and developmental regression.
Conclusions: This study provides the first estimate of ASD prevalence in Qatar which is consistent with recent international studies. The instruments and methods employed should help in designing comparable surveys in the region. We estimated that 50,500 children under age 5 and 187,000 youths under age 20 have ASD in the Gulf countries. This estimate should guide planification of health and educational services in the Gulf countries for a population that is young and growing fast.