Since 2000, the rate of diagnosis for children with Autism Spectrum Disorder has nearly tripled. In 2000, approximately 1 of every 150 children received a diagnosis of ASD. In 2014, that number had skyrocketed to 1 of every 59 children.
The causes for this increase are a source of argument for many experts. There has been a broadening of the diagnostic criteria for Autism Spectrum Disorder. Many children who were previously diagnosed with an intellectual disability are now being classified as “on the spectrum.” It would seem one diagnosis is being substituted for another.
According to Santhosh Girirajan, a Penn State geneticist who specializes in neurodevelopmental disorders, there has been “no change in the overall proportion of children enrolled in the special education cohort from 2000 to 2010.” This suggests that the perception of a sharp increase in the number of ASD cases is due, at least in part, to the aforementioned diagnostic substitution. Girirajan and his research team published their findings in a July 2015 study published in the American Journal of Medical Genetics. (1)
Some experts have suggested that better “access to pediatricians and school-based health centers may lead to improved recognition of ASD.” (2) These factors, along with an improved understanding of ASD and better diagnoses may have contributed to the increased rate of diagnosis. Regardless of the root cause, with the sheer numbers of children being designated as ASD, there are considerable personal and public health questions.
One of those questions centers around obesity and the metabolic diseases related to it. Researchers at Children’s Hospital of Philadelphia (CHOP), the University of Pennsylvania and six other centers have just published a study which confirms what many of us working with the ASD population in the fitness field already knew. Children with developmental delays, including autism spectrum disorder (ASD), are far more likely to be overweight or obese compared with the general population.
According to the research team’s findings, published online by The Journal of Pediatrics, kids “on the spectrum” have up to a 50% greater risk of obesity than neurotypical children.
While there have been previous studies to confirm the obesity risk among children with Autism, this study is the first large-scale study to examine if children with other developmental disabilities are also at increased risk for developing obesity. Also, the researchers examined connections between excess weight gain and the presence of other medical, behavioral, developmental, or psychiatric conditions.
The CHOP study was a large sample study, including nearly 2,500 children between the ages of 2 and 5 years. This age group is particularly relevant to the question of obesity risk. Body fat and BMI (referred to as adiposity) in children increases rapidly in the first year of life. Then, between the ages of about 2 and 5, adiposity steadily decreases, bottoming out at around 5-6 years. At this point, referred to as adiposity rebound, both body fat and BMI begin to increase again. High levels of adiposity at the age of 5 is linked to obesity later in life. (3)
Research has found that early-onset obesity is linked to persistent obesity later in life. The period between 5 and 7 years of age, when adiposity is beginning it’s rebound, is often called a “critical period” for obesity onset or avoidance. (4) High levels of adiposity at the beginning of this period, then, bodes poorly for the child’s future.
This study is also the first large sample study to regard children with both ASD or developmental delays similarly for the assessment of obesity risk. Among kids with ASD, a higher degree of impairment and more severe symptoms were correlated to a greater risk of developing obesity by age five.
Conducted as part of the Study to Explore Early Development (SEED,) the multisite study analyzed 668 children with ASD, 914 with developmental delays or disorders and 884 neurotypical children who served as controls. Height and weight was measured during clinical visits. ASD severity was assessed using the Ohio State University Global Severity Scale for Autism.
The findings were rather astonishing. Children with ASD were 1.57 times more likely to be overweight or obese than the general population. Those with developmental delays had a risk of obesity 1.38 times that of the general population. In children with severe ASD, the risk was even more profound. These children bore a risk of obesity 1.7 times higher than the children with mild ASD symptoms. (5)
Susan E. Levy, MD, MPH, the study’s lead author and medical director of the Center for Autism Research at CHOP said, “These findings make it clear that monitoring these children for excess weight gain at an early age is critical, and that prevention efforts should be expanded to include not just children with ASD, but those with other developmental diagnoses, as well.”
“We need more research to understand why these children are more likely to develop obesity, and which children are at the highest risk,” said Levy. Children with ASD often suffer from other disorders which may be factors in excess weight gain. These include endocrine disorders, genetic disorders, gastrointestinal symptoms, sleep disturbances, side effects from medications or dietary rigidity (food choice limits and selectivity,) among others.
The obesity risk for ASD children is influenced by neuromuscular issues as well. A large body of research has shown a higher instance of gross motor deficits in children with ASD. They often lack proximal strength (strength in the muscles of the core and near the body’s midline,) hip flexibility/mobility and trunk stability. Compromised gait pattern is a pervasive problem for this population, as is kinesthetic awareness.
ASD children struggle with movement patterns that are “natural” to neurotypical kids. Squatting, lunging, pushing and pulling – multi-joint movements – are poorly executed (if at all) because they struggle to recruit the deep stabilizer muscles associated with success in these movements. Segmental stabilization is difficult for ASD children. Rooting the lower body to perform a throw, lift a weight or perform a pulling movement doesn’t occur as it would for the neurotypical. Full body movement (“en bloc”) or the use of momentum to complete a task is common.
These gross motor deficits can make exercise, and even the activities of daily living, difficult to do effectively. Inactivity becomes the preferred state. Hip flexors shorten and weaken over time, contributing to back pain and postural issues. Anterior chain muscles tighten, contributing further to the posture problems. Low back pain can ensue, which can be especially problematic for non-verbal individuals or those with other communication deficits, since they can’t communicate their physical discomfort effectively.
Because a large portion of the readily available fitness opportunities for children revolve around sports or sport-related activities, opportunities to participate become limited for ASD children. Their gross motor deficits and other neuromuscular issues place them at a disadvantage in the expression of movement, making sports activities a practical impossibility for most.
For the ASD child between 2 and 5, fitness and exercise activities should be focused on progressive benefits like increasing general strength, improving motor planning/task execution and increasing stability and control during the performance of gross motor movements. Preventative benefits like encouraging an active lifestyle by providing opportunities for successful activity completion and creating more physical literacy for these children also matter. These latter two will help reduce pain and discomfort from compensatory motor patterns and reduce future reliance on others to complete the tasks of daily living.
The CHOP findings underscore the urgency of addressing the obesity issue for ASD kids. The results may offer some direction related to early intervention. The authors suggest that clinicians monitor children who receive a diagnosis of ASD or developmental delays/disorders for signs of excess weight gain, and that they provide specific guidance for their parents in an effort to prevent obesity. Parents should discuss with their medical caregiver any concerns they have about their child who may be showing signs of obesity.
Perhaps a more proactive way to address the obesity risk is to institute more effective programs for activity for these individuals. Giving thought to their actual needs and deficits before beginning an anti-obesity program may help alleviate the problem before it becomes one. Starting these programs with kids as young as 2 or 3 would go a long way to improving health outcomes later in life.
Keep the faith and keep after it!
- Polyak A, Kubina RM, Girirajan S. 2015. Comorbidity of intellectual disability confounds ascertainment of autism: implications for genetic diagnosis. American Journal of Medical Genetics Part B 168B:600–608.
- Mandell DS, Palmer R. Differences Among States in the Identification of Autistic Spectrum Disorders. Arch Pediatr Adolesc Med. 2005;159(3):266–269.
- Lawlor, D and Chaturvedi, N, Treatment and prevention of obesity – are there critical periods of intervention?; International Journal of Epidemiology, February 2006
- Dietz, WH, Critical periods in childhood for the development of obesity; The American Journal of Clinical Nutrition, May 1994
- Susan E. Levy, et al., Relationship of Weight Outcomes, Co-Occurring Conditions, and Severity of Autism Spectrum Disorder in the Study to Explore Early Development. The Journal of Pediatrics, 2018