Autism spectrum disorder (ASD) is a complex developmental disability that affects how a person communicates, interacts, behaves, and learns. The Centers for Disease Control and Prevention (CDC) estimates that around 1 in 44 children in the United States has autism spectrum disorder (ASD) based on the latest prevalence data from 2018. This marks a significant increase from previous decades. So what’s behind the rising autism rates? Here’s a closer look at the key facts and statistics on autism spectrum disorder prevalence among children.
Autism Diagnoses are Rising
The reported prevalence of autism has increased dramatically over the past few decades. For example, data from the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network shows:
- In 2000, around 1 in 150 8-year-old children were identified with ASD.
- In 2010, this had risen to 1 in 68.
- By 2016, approximately 1 in 54 children were identified with ASD.
- In 2018, an estimated 1 in 44 children were diagnosed with ASD.
This upward trend in autism rates has also been documented globally, with estimates ranging from 1% to 2% of children worldwide having ASD.
The reasons behind the rise are complex. Increased awareness, screening and earlier diagnoses have played a major role. There also may be environmental risk factors. It’s unlikely the increase stems from vaccines, however, as thorough scientific research has shown no link between vaccines and autism (UCLA).
Boys are Diagnosed with Autism More than Girls
Autism spectrum disorder is around 4 times more common in boys than girls. According to the CDC’s ADDM data, 1 in 34 boys were identified with ASD in 2018, compared to 1 in 144 girls.
Researchers are still investigating the reasons for this gender difference. Possible biological and social factors include:
- Genetic and hormonal differences.
- Differences in how girls may manifest symptoms.
- Gender bias in screening and diagnosis.
The gap has narrowed slightly in recent prevalence reports. And clinicians are getting better at recognizing autism in girls. But more work is needed to ensure equal identification among genders.
Autism Prevalence Varies by Race and Ethnicity
The CDC’s data also reveals differences in autism prevalence across racial, ethnic, and socioeconomic groups. In 2018, non-Hispanic white children were more likely to be identified with ASD than non-Hispanic black or Hispanic children.
However, these gaps have narrowed over time. And studies show when adjusting for socioeconomic factors, differences in prevalence by race and ethnicity are reduced or disappear.
Unequal access to screening and diagnostic services likely contributes to the disparity. More outreach and research is needed to understand and address these differences fully.
Most Children Are Still Diagnosed After Age 4
Catching autism early is key, as early intervention can greatly improve outcomes. The American Academy of Pediatrics recommends universal screening for ASD at 18 and 24 months.
However, many children are diagnosed much later. The median age of diagnosis is around 4 years, according to the CDC. Their 2018 data found:
- 37% of children were diagnosed by age 3.
- 18% were diagnosed between ages 3 and 4.
- 29% were diagnosed between ages 5 to 8.
- 16% were diagnosed after age 8.
Delayed diagnosis prevents children from accessing crucial therapies and support when they’re likely to benefit most. Efforts to promote and improve early screening are critical for the wellbeing of children with ASD.
Autism Prevalence is Rising Globally
While the latest statistics are for the United States, autism is a global public health concern. The estimated prevalence worldwide is between 1-2% of children, according to Autism Speaks.
Studies from South Korea and other countries show similarly high and rising autism rates. Increased awareness and research around the world is identifying more cases. Though the reasons for the worldwide rise remain complex and multi-faceted.
More work is also needed to improve autism identification and services in low-resource regions. The needs of individuals with autism and their families extend across borders and cultures.
Ongoing Monitoring is Needed
The figures highlight the urgent need for continued monitoring of autism rates and trends. Ongoing surveillance and research is critical to:
- Understand and address the increase in autism over time.
- Ensure early and equitable identification among all groups.
- Plan for the service needs of the autism community.
- Discover potential risk factors that may inform prevention.
Programs like the ADDM Network provide crucial data to guide efforts to support individuals with autism and their families. Continuing this work will require commitment from policymakers, clinicians, and the public.
Autism Prevalence FAQs
Here are answers to 5 of the most frequently asked questions about autism rates and statistics:
How many people have autism worldwide?
Global estimates indicate around 1-2% of the world’s population has autism spectrum disorder. This equates to over 70 million individuals worldwide based on a meta-analysis in JAMA Psychiatry. However, prevalence varies across regions and precise counts are lacking for many low-resource countries.
What is the main cause of the increase in autism?
There is no single cause. The rise stems from a complex mix of greater awareness, expanded diagnostic criteria, earlier identification, and potential shifts in risk factors. However, vaccines are NOT a credible cause, as rigorous research has found no link between vaccines and autism.
Are autism rates still going up?
In the U.S., the latest CDC data shows autism prevalence continuing to increase as of 2018. The rates have risen steadily for decades, though time will tell if they plateau moving forward. Monitoring is needed to track trends and inform policies to meet the growing needs.
Are more children being misdiagnosed with autism?
There is little evidence of widespread autism misdiagnoses. Diagnostic criteria have become more precise over time. Clinicians look for established symptoms and behaviors before diagnosing autism spectrum disorder. However, earlier identification means some “milder” cases may now get appropriately diagnosed.
Is autism more common in certain regions?
In the U.S., the CDC’s data does not show major regional differences. Globally, autism prevalence appears similar across studied countries. However, reported rates vary, likely reflecting differences in study methods and access to services. Much more research is needed on the worldwide epidemiology.