Regularly analyzing the prevalence of autism spectrum disorder (ASD) is important to inform policies and strategies for proper management. The present study aimed to esti-mate trends in ASD prevalence according to age and time in Korean children.
We monitored the annual prevalence of ASD in children aged 2 to 18 years based on information from Statistics Korea and the Korean National Health Insurance Service. We estimated changes in prevalence between 2011 and 2021 after stratifying partici-pants into three age groups. Furthermore, we analyzed the prevalence of ASD by birth year.
The highest level of prevalence appeared in children aged 6 years, and thereafter, it de-clined with age. The prevalence of ASD in children aged 2 to 18 years increased from 0.05% in 2011 to 0.12% in 2021. During the same time, the prevalence in preschool children (2 to 5 years) remarkably increased from 0.04% in 2011 to 0.12% in 2021, while the prevalence in adolescents (13 to 18 years) increased from 0.05% in 2011 to 0.09% in 2021. The prevalence of ASD notably increased during the coronavirus disease 2019 (COVID-19) pandemic (2020 to 2021). Among children born between 2011 and 2015, the prevalence of ASD was higher for children with recent birth years, especially during the COVID-19 pandemic.
The overall ASD prevalence in children and adolescents in Korea seems to be increasing, especially in preschool children during the COVID-19 pandemic. Early and more effec-tive interventions are necessary for Korean children.
For several decades, children presenting with developmental deviations in language and social and repetitive behaviors have been distinguished from children having other mental disorders and given a diagnosis of autism spectrum disorder (ASD) [
Unfortunately, over the past decade, the prevalence of ASD diagnoses has in-creased considerably. A report from the United States focused on the prevalence and features of ASD among children aged 8 years in 2018 whose parents or guardians lived in 11 Autism and Developmental Disabilities Monitoring Network sites. The researchers found that 23 per 1,000 children (i.e., one in 44) aged 8 years had ASD and that the prevalence and median age of ASD identification varied widely across sites. These findings indicated a significant increase in ASD prevalence compared to 2014 (16.3 per 1,000). Furthermore, despite some small differences between regions, the prevalence of ASD was similar across racial groups in America. Potential reasons for the general increase in the prevalence of ASD include the extension of diagnostic criteria, the possibility of an earlier age at diagnosis age, better public awareness, or a mixture of factors; however, a consensus is yet to be reached [
According to earlier research using information from the Korean National Health Insurance Service (NHIS), the ASD prevalence was lower than the prevalence derived from questionnaire surveys [
To date, the ASD survey methodology has not been standardized. Existing studies all have unique designs that reflect the domestic social and health policies for children with disabilities [
We performed this retrospective study using information from the NHIS in Korea. We used data on ASD (codes F84.0, F84.1, F84.5, F88.8, or F88.9 according to the International Classification of Diseases [ICD], 10th revision), as in a previous study, through the homepage of the NHIS (
We estimated the number of patients who met the conditions every year by calculating the number of people who visited clinics at least once a year for the treatment of ASD. Information on the age and sex of the aggregated patients was also obtained. From the homepage of Statistics Korea (
The annual prevalence of ASD was derived by dividing the number of patients by the estimated population each year. We also calculated the prevalence of ASD by age and sex. Children and adolescents were stratified into three age groups (2–5, 6–12, and 13–18 years). Although ASD is sometimes diagnosed as early as the age of 18 to 24 months, the authors did not analyze those under the age of 2 [
Statistical values such as
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Institutional Review Board of Chuncheon Sacred Heart Hospital (CHUNCHEON 2022-01-015). Written informed consent by the patients was waived due to a retrospective nature of our study.
Our analysis of time trends in prevalence based on age group showed that the prevalence of ASD in Korean children (2 to 18 years) increased markedly from 0.05% in 2011 to 0.17% in 2021 (
We analyzed whether the trend of increasing ASD prevalence with age was similar every year (
In addition, the slopes of increasing ASD prevalence were not the same according to age based on the year of birth (2011 to 2015) (
The overall prevalence of ASD in children aged 2 to 18 years steadily increased from 2011 to 2021. Notably, the prevalence of ASD in preschool children (2 to 5 years of age) increased from 0.06% to 0.23% during the 11-year study period. The increasing prevalence of ASD in Korea is consistent with that of other developed countries [
Although the precise reason has not been definitively established, the increasing trend of ASD prevalence may be related to environmental changes and increased community awareness regarding the condition globally [
According to a global estimate of ASD prevalence prepared using the results of those studies, the median prevalence in 2022 is 65/10,000, which is higher than the rate of 62/10,000 reported in 2012. Most of the studies reported in this study were performed in the United States and Europe, Western Pacific, and South-East Asia, and a few studies from Africa and the Middle East were also included [
The observed patterns in the changing prevalence rate according to age in Korea may be explained by opinions specific to Korean culture, such as “a feeling of rejection about seeing a psychiatrist” and “fear of being diagnosed with ASD or registration as a person with disabilities” [
A typical limitation of research using information from the NHIS is diagnostic accuracy. Furthermore, since the prevalence of ASD is estimated on the basis of patients’ hospital visits, it may be affected by factors like ability to access clinics, patients’ socio-economic status, disease perceptions, or behavioral changes according to external considerations such as the COVID-19 pandemic. In other words, some patients may not seek medical care even if ASD has developed or if ASD symptoms persist. For this reason, all analyses using the NHIS data should be interpreted carefully. In fact, a previous study reported a higher prevalence rate than our findings (2.64% of the total population in 7 to 12 years old between 2005 and 2009, n=55,266) [
Clearly, national epidemiological studies using a different approach are necessary to determine the trends in ASD prevalence in Korean children. During the COVID-19 pandemic, hospital visits generally decreased significantly (Organization for Economic Co-operation and Development statistics on doctor consultations). Nevertheless, the prevalence of ASD in 2020 to 2021 markedly increased. As an explanation for the increased prevalence of ASD during the COVID-19 pandemic, we suggest that measures like mask-wearing during the COVID-19 pandemic might have interfered with children’s development, especially language development, in which children learn by looking at their caregivers’ mouths and facial expressions [
In conclusion, we first estimated the prevalence of ASD by year based on the Korean NHIS database and observed temporal trends over the past 10 years, including the COVID-19 pandemic. The overall prevalence of ASD in Korean children aged 2 to 18 years increased from 2011 to 2021, especially in 2 to 5 years old during the COVID-19 pandemic. In contrast, the prevalence of ASD in adolescents (13 to 18 years old) tended to increase slightly during the same period. Our results suggest that strategies need to be modified for timelier and more effective prevention and care of ASD in Korean children.
No potential conflict of interest relevant to this article was reported.
Conceptualization: JY and JYL. Data curation: HE. Formal analysis: HE. Methodology: MK. Writing-original draft: HE. Writing-review & editing: MK, JKY, EB, JY, and JYL.
Time trends in the prevalence of autism spectrum disorder (ASD) in Korean children aged 18 years and under from 2011 to 2021. Changes in ASD prevalence in each age group from 2011 to 2021 were observed in the following age groups: overall (2–18), 2–5, 6–12, and 13–18 years. COVID-19, coronavirus disease 2019.
Comparison of the prevalence of autism spectrum disorder (ASD) by age group among the years 2011, 2014, 2017, and 2021. The slope of ASD prevalence by age was different between the years. The prevalence of ASD in 2021 was much higher than in other years.
Comparison of the prevalence of autism spectrum disorder by age among children born from 2011 to 2015. Among children who were born in 2011, 2012, and 2013, the slopes of the increasing trend lines were similar. In contrast, in children born in 2014 and 2015, the slopes of prevalence with growth increased sharply. COVID-19, coronavirus disease 2019.
The estimated prevalence rate (%) of pediatric autism spectrum disorder in Korea from 2011 through 2021
Age (yr) | 2011 |
2012 |
2013 |
2014 |
2015 |
2016 |
2017 |
2018 |
2019 |
2020 |
2021 |
|||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | Boy | Girl | |
0 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
1 | 0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.01 | 0.00 | 0.01 | 0.00 | 0.01 | 0.00 |
2 | 0.05 | 0.01 | 0.05 | 0.01 | 0.05 | 0.02 | 0.06 | 0.02 | 0.05 | 0.01 | 0.05 | 0.01 | 0.05 | 0.01 | 0.06 | 0.02 | 0.07 | 0.02 | 0.11 | 0.03 | 0.14 | 0.05 |
3 | 0.10 | 0.02 | 0.12 | 0.03 | 0.14 | 0.03 | 0.15 | 0.03 | 0.13 | 0.04 | 0.13 | 0.03 | 0.14 | 0.04 | 0.15 | 0.04 | 0.17 | 0.05 | 0.22 | 0.06 | 0.33 | 0.12 |
4 | 0.13 | 0.03 | 0.11 | 0.03 | 0.15 | 0.04 | 0.16 | 0.04 | 0.19 | 0.04 | 0.18 | 0.04 | 0.16 | 0.04 | 0.22 | 0.05 | 0.26 | 0.07 | 0.29 | 0.08 | 0.39 | 0.12 |
5 | 0.10 | 0.02 | 0.14 | 0.03 | 0.14 | 0.03 | 0.16 | 0.04 | 0.17 | 0.04 | 0.22 | 0.05 | 0.21 | 0.05 | 0.24 | 0.05 | 0.28 | 0.06 | 0.32 | 0.10 | 0.44 | 0.12 |
6 | 0.10 | 0.02 | 0.13 | 0.02 | 0.17 | 0.03 | 0.17 | 0.04 | 0.19 | 0.05 | 0.22 | 0.05 | 0.27 | 0.05 | 0.27 | 0.07 | 0.32 | 0.06 | 0.33 | 0.09 | 0.49 | 0.13 |
7 | 0.12 | 0.02 | 0.11 | 0.02 | 0.12 | 0.02 | 0.15 | 0.03 | 0.16 | 0.03 | 0.17 | 0.04 | 0.22 | 0.05 | 0.25 | 0.05 | 0.27 | 0.07 | 0.28 | 0.05 | 0.38 | 0.10 |
8 | 0.10 | 0.02 | 0.10 | 0.02 | 0.10 | 0.02 | 0.11 | 0.02 | 0.13 | 0.02 | 0.14 | 0.03 | 0.17 | 0.04 | 0.23 | 0.04 | 0.26 | 0.05 | 0.27 | 0.06 | 0.32 | 0.07 |
9 | 0.09 | 0.02 | 0.09 | 0.02 | 0.10 | 0.02 | 0.09 | 0.02 | 0.11 | 0.02 | 0.14 | 0.02 | 0.15 | 0.03 | 0.18 | 0.04 | 0.23 | 0.05 | 0.25 | 0.05 | 0.29 | 0.06 |
10 | 0.08 | 0.02 | 0.10 | 0.02 | 0.09 | 0.02 | 0.10 | 0.02 | 0.10 | 0.02 | 0.11 | 0.02 | 0.15 | 0.03 | 0.16 | 0.03 | 0.19 | 0.04 | 0.22 | 0.05 | 0.28 | 0.06 |
11 | 0.08 | 0.02 | 0.08 | 0.02 | 0.10 | 0.02 | 0.09 | 0.01 | 0.10 | 0.02 | 0.10 | 0.01 | 0.12 | 0.02 | 0.15 | 0.03 | 0.16 | 0.04 | 0.20 | 0.04 | 0.25 | 0.06 |
12 | 0.09 | 0.02 | 0.10 | 0.02 | 0.09 | 0.02 | 0.10 | 0.02 | 0.09 | 0.02 | 0.13 | 0.03 | 0.12 | 0.02 | 0.14 | 0.02 | 0.19 | 0.04 | 0.20 | 0.04 | 0.23 | 0.05 |
13 | 0.11 | 0.02 | 0.10 | 0.02 | 0.11 | 0.02 | 0.09 | 0.02 | 0.10 | 0.02 | 0.10 | 0.03 | 0.13 | 0.03 | 0.14 | 0.02 | 0.16 | 0.03 | 0.18 | 0.04 | 0.20 | 0.04 |
14 | 0.08 | 0.01 | 0.12 | 0.02 | 0.10 | 0.02 | 0.10 | 0.02 | 0.10 | 0.02 | 0.11 | 0.02 | 0.11 | 0.02 | 0.11 | 0.03 | 0.13 | 0.02 | 0.15 | 0.03 | 0.17 | 0.03 |
15 | 0.07 | 0.01 | 0.09 | 0.01 | 0.11 | 0.02 | 0.10 | 0.02 | 0.11 | 0.02 | 0.11 | 0.02 | 0.12 | 0.02 | 0.11 | 0.03 | 0.13 | 0.03 | 0.12 | 0.02 | 0.16 | 0.03 |
16 | 0.07 | 0.01 | 0.08 | 0.02 | 0.09 | 0.01 | 0.12 | 0.02 | 0.12 | 0.02 | 0.12 | 0.02 | 0.12 | 0.02 | 0.12 | 0.02 | 0.12 | 0.03 | 0.14 | 0.03 | 0.14 | 0.02 |
17 | 0.06 | 0.01 | 0.08 | 0.02 | 0.08 | 0.02 | 0.09 | 0.02 | 0.12 | 0.02 | 0.12 | 0.03 | 0.12 | 0.02 | 0.11 | 0.02 | 0.13 | 0.02 | 0.14 | 0.03 | 0.15 | 0.03 |
18 | 0.07 | 0.01 | 0.08 | 0.02 | 0.09 | 0.02 | 0.10 | 0.02 | 0.10 | 0.02 | 0.14 | 0.02 | 0.14 | 0.02 | 0.14 | 0.02 | 0.13 | 0.02 | 0.15 | 0.03 | 0.16 | 0.03 |