One in Six US Children Diagnosed With a Developmental Disability

By Reuters Staff

September 27, 2019

NEW YORK (Reuters Health) - The prevalence of children diagnosed with any developmental disability increased significantly in recent years, potentially due to greater awareness and access to health care in some demographic and socioeconomic groups, a new analysis indicates.

Overall, about one in six U.S. children aged 3 to 17 years (about 17%) had a developmental disability between 2009 and 2017, up from about 14% between 1997 and 2008, Dr. Benjamin Zablotsky of the Centers for Disease Control and Prevention (CDC) and colleagues report in Pediatrics, online September 26.

"The prevalence of any developmental disability increased among boys, older children, non-Hispanic white and Hispanic children, children with private insurance only, children with birth weight >= 2500 g, and children living in urban areas and with less-educated mothers," they report. Their analysis was based on data from the 2009 to 2017 National Health Interview Survey (NHIS).

The increase in developmental disabilities between 2009 and 2017 was driven largely by increases in attention-deficit/hyperactivity disorder (ADHD, 8.5% to 9.5%, P<0.01), autism spectrum disorder (ASD, 1.1% to 2.5%, P<0.001), and intellectual disability (ID, 0.9% to 1.2%, P<0.05).

The period also saw a significant decline in any other developmental delay (4.7% to 4.1%, P<0.05).

The uptick in diagnosed ADHD in U.S. children and adolescents since the late 1990s has been "well documented," the investigators note, although there is evidence that the prevalence of ADHD symptoms and impairment has remained steady over time.

"Taken together, this suggests that the increases in diagnosed prevalence could be driven by better identification of children who meet criteria for ADHD," they write.

Updated guidelines on diagnosis and treatment of ADHD released in 2011 by the American Academy of Pediatrics may have influenced diagnostic practices over the study time period, and the availability of effective treatment may also be related to increases in the diagnosis of ADHD, Dr. Zablotsky and colleagues say.

The uptick in ASD diagnoses is also not surprising as this has been shown in the U.S. and other industrialized countries in recent decades, the researchers say. "However, understanding changes to ASD prevalence remains particularly challenging given that the diagnosis of ASD is based on a symptom profile, and health care provider and school practices for ASD screening, diagnosis, and classification continue to evolve," they note.

A "sizable" portion of the ASD increase is likely due to improved identification of children with ASD linked to increased awareness among parents and changing practices among providers, including universal screening by 18 to 24 months and ongoing monitoring of a child's development as recommended in 2007, they write.

The increase in the prevalence of ID appears to coincide with changes to the wording or ordering of survey questions in the NHIS. The prevalence of ID was relatively stable between 1997 and 2008 when the survey asked about "mental retardation" but was 72% higher in 2011 to 2013 when the survey asked about "intellectual disability, also known as mental retardation," Dr. Zablotsky and colleagues explain.

The wording changes "may have decreased social desirability pressures (eg, parents may be more comfortable endorsing ID rather than mental retardation) while increasing the ability to recognize and correctly endorse the condition by including both terms," they note.

"Other developmental delay" was the only condition to show a statistically significant decrease over time. It may be that parents responding to the NHIS have become less likely to pick this category because their children have increasingly been diagnosed with another specific condition on the survey.

Dr. Zablotsky and colleagues say more research is needed to "better understand the characteristics of children with developmental disabilities, the complex risk factors associated with developmental disabilities, and the accessibility of services and interventions, which have been shown to improve long-term outcomes for those diagnosed with a developmental disability."


Pediatrics 2019.