An early diagnosis of autism spectrum disorder, a type of developmental disorder was found to be effective from routine health checkups of infants at 18 months of age.
Health checkups are provided at no cost to all children at 18 months and 3 years of age in Japan. Doctors at Shinshu University School of Medicine designed a study to utilize the 18-month health checkup as an opportunity to screen for autism spectrum disorder (ASD), because early detection of ASD can lead to better prognosis for children with ASD.
Infants born between the year 2009 to 2012 in Okaya city, located in Nagano prefecture, participated in the study to investigate the incidence and risk factors of ASD organized by Shinshu University School of Medicine, Department of Child and Adolescent Developmental Psychiatry and Department of Psychiatry; Associate Professor Daimei Sasayama, Professor Hideo Honda, Professor Shinsuke Washizuka, and Professor Tetsuo Nomiyama of the Department of Preventative Medicine and Public Health.
1067 children, or 85% of the children born in Okaya city during the 3-year period received the 18-month health checkup. With the help of Shinano Medical and Welfare Center, 3.1% of the children examined were later diagnosed to have ASD by the time they became of school age (6 years old by April 1st). Many of these children were noted to have impaired motor skills and social communication skills at 18-months. The results of this study suggest that the medical examination that most children in Japan receive at 18 months can be an effective method to screen for ASD.
This study was published online July 21, 2020 in the Journal of Autism and Developmental Disorders, one of the most prestigious international autism journals.
The proportion of people diagnosed with ASD has increased worldwide over the last two decades. A 2014 US survey reported a prevalence of 1.68% in 8 year-olds. One of the main reasons for the increase in prevalence in recent years is the improvement of screening accuracy.
Early detection and early intervention of ASD is important for improving the prognosis of children with ASD. However, it is considered difficult to detect ASD in children under the age of 2 using common screening tools used today. Okaya City strives to improve the accuracy of early detection of autism spectrum disorders during the 18-month health checkup and experienced public health nurses carefully screen each child. In addition, they have established a system in which children who are suspected of having ASD are referred to the Shinano Medical and Welfare Center for early diagnosis and support.
This study investigated the cumulative incidence of autism spectrum disorders in Okaya city, where an early diagnosis system is in place. In addition, the team examined the features that were found at age 18-months in children who were later diagnosed with ASD.
Research methods and results
The research subjects were 1,067 children who were born between April 2, 2009 to April 1, 2012, who received the 18-month old health checkup in Okaya City. A survey of the medical information provided by the Shinano Medical and Welfare Center found that 33 of the 1,067 subjects (22 boys, 11 girls) has been diagnosed with autism spectrum disorder before entering elementary school (cumulative incidence 3.1% [4.3% of boys, 2.0% of girls]).
A comparison of 33 children with ASD and 1,034 children without autism revealed that children diagnosed with ASD tended to have lower fine and gross motor skills and social communication skills at the time of the 18-month health checkup.
Implications/ Future plans
The cumulative incidence reported in this study was the highest incidence of medically diagnosed ASD in the general population reported compared to previous studies. These results suggest that a diagnosis with high sensitivity would be possible by establishing a careful screening system at the 18-month health checkups. In addition, children with ASD have been shown to have underdeveloped fine and gross motor skills and social communication abilities at the age of 18-months, which are factors that predict ASD at an early stage. It is anticipated that the continuation of research will lead to the development of an early diagnosis system for autism spectrum disorders that utilizes infant health checkups.
Sasayama, D., et al. (2020) Brief Report: Cumulative Incidence of Autism Spectrum Disorder Before School Entry in a Thoroughly Screened Population. Journal of Autism and Developmental Disorders. doi.org/10.1007/s10803-020-04619-9.