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IAN Research Report #4: School Settings, Plus Height and Weight

Date First Published: December 7, 2007

One-on-One Aides by State
Children with ASDs: Classroom Settings Over the Years
IAN Reports on New Weight and Height Data


The Interactive Autism Network (IAN) has one overarching purpose: to accelerate the pace of autism research. Toward this goal, we continue to collect information via the Internet from families of children with Autism Spectrum Disorders (ASDs) from throughout the United States. More than 19,500 individuals -- children with ASDs and their mothers, fathers, and siblings -- have registered to participate so far.

Often, participants in research never learn what became of the data they provided, the samples they gave, or the tests they took. This is not the case with IAN families. We view all of you who are sharing your information with us as active participants in this project. Through these IAN Research Reports we share preliminary information with you, both as a way to thank you and to acknowledge you as ongoing partners in the project. In addition, your comments and suggestions are taken into account as we choose which IAN questionnaires to develop next, what topics to cover on the IAN Community website, or which ideas to explore in these reports.

Remember, we value your feedback and comments. Share your ideas, concerns, and opinions by writing to


One-on-One Aides: Use by State

In our most recent IAN Research Report (September '07), we provided information on the number of children with ASDs who are assigned a one-on-one aide or personal assistant in the classroom. Roughly half of children with ASDs were assigned such a "shadow," and use of full- or part-time aides was fairly high across diagnoses and across grade levels.

Following our report, an IAN parent wrote to ask: "How does the use of one-on-one aides vary by state?" To respond to this request, we returned to the data and took a simple count. In Table 1, we present the results. Please note that we only display states for which we have more than 45 children with ASDs registered in IAN who also answered the question about aides in the classroom.

Table 1. Use of One-on-One Aides by Children with ASDs by State as of 11/5/07

States and Territories with >45 children registered in IAN who answered the "Aide" question

Have Part- or Full-Time Aide

Kansas (n=53)
Connecticut (n=104)
Colorado (n=56)
Alabama (n=46)
Massachusetts (n=143)
New Jersey (n=233)
Minnesota (n=76)
Missouri (n=167)
Pennsylvania (n=262)
Kentucky (n=57)
Oregon (n=70)
New York (n=398)
Ohio (n=195)
Illinois (n=172)
California (n=355)
Maryland (n=183)
Wisconsin (n=50)
Virginia (n=156)
Indiana (n=119)
Texas (n=269)
Arizona (n=60)
Michigan (n=135)
Washington (n=120)
Georgia (n=132)
Tennessee (n=65)
Florida (n=261)
North Carolina (n=104)


Clearly, the number of children receiving the services of a personal assistant varies a great deal by state. This likely reflects different programming practices in different locales.

Keep in mind that this information is based on IAN registrants only. Their experience may differ from that of the general population, and the smaller the number of children with ASDs representing any one state, the less likely statewide experience is reflected in this number. These data are difficult to interpret, as well. Is a high number of aides an indication that school districts are meeting students' needs, or does the use of aides become a substitute for providing other meaningful types of accommodations? What techniques and practices serve which children with ASD best? These are all important questions for research to address.

Children with ASDs: Classroom Settings Over the Years

In our most recent IAN Research Report (September '07), we examined how much of the day children with ASDs were spending in a special education vs. a regular education setting, and how this varied by diagnosis. We now look at the same issue with regard to grade level. Do children spend less and less time in a special education as compared with a regular education setting as they grow?

Not exactly. Our preliminary data do show that more children spend more of their day in special education settings at younger ages. During the elementary grades, the proportion of the day spent in a special education setting decreases for many children. It increases slightly again, however, as children age. (See Figure 1.)

Figure 1. Children with ASDs: Classroom Setting by Grade LevelBar chart showing use of one-on-one aides by grade level for children with ASDs

Perhaps part of the answer is the growing social complexity faced by older children who attend regular classes with their peers. The social nuances at play in a middle or high school setting may be more challenging for children with ASDs than those faced in elementary school. There may be increasing maturity and competence, but also an increasing need for a sheltered part of the day.

In addition, note that fewer families of older children are participating in IAN. We have less information about older children, and that makes our analysis less certain. Are the highest functioning teens simply missing from our sample? Or do our data reflect a true shift from a more inclusive setting back to a more restrictive one for some students? Further study -- and more participating teenagers -- will be needed before we can answer that question.

IAN Reports on New Weight and Height Data

Preliminary analysis shows that children with ASDs tend to be taller than expected for their age, and heavier than expected for their height, compared with typical peers.


The IAN Weight and Height Questionnaire was launched on the afternoon of October 22, 2007. Families participating in IAN Research were notified, and got out their scales and tape measures. By the end of the next day, October 23, families had submitted height and weight measurements for more than 1,000 children. By November 21, IAN had received data for nearly 2,000 children with ASDs and more than 1,200 of their nonaffected siblings. 

Why is body size an important topic to investigate?

There are at least two major reasons body size, which is measured by head circumference, weight, height, and body mass index (BMI), is an important topic to investigate in autism. First of all, differences in any of these may help point the way to specific subtypes of autism -- different kinds of autism characterized by measurable physical, biochemical, or other factors, and which may be due to different causes. In addition, issues related to weight and BMI may be related to the future health of individuals with ASDs.


A recent paper, "Clinical, Morphological, and Biochemical Correlates of Head Circumference in Autism," is an excellent example of research tying a certain physical picture in ASD to other important characteristics. Studying 241 individuals with autism, ages 3 to 16, researchers found that head size, as well as overall body size, tended to be large and that those with the largest head size also tended to have more impaired adaptive behaviors and less impaired IQ, motor development, and verbal language, as well as a family history of allergic/immune disorders. 1  Another study, this one focusing on 28 children with autism and 25 with Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), discovered growth of body length was accelerated in very young children with ASDs. 2

In a preliminary look at the data, what have we found?

Children with ASDs: Taller, Heavier Than Typical Peers

To compare children with ASDs and their unaffected siblings -- who were considered "typical peers" for the purposes of this analysis -- IAN used both height and BMI. (BMI is a measure that is used to calculate whether someone's weight is more or less than would be expected for his or her height.)


As a group, children with ASDs appear to be taller than their typical peers. Children with Asperger's Syndrome and Autism, specifically, appear taller than those with PDD-NOS who, in turn, do not differ from typical children in height. (See Figure 2.)

Figure 2. Height Status: Children with ASDs and Unaffected Siblings -- Nov. 21, 2007
Bar chart Nov 28 showing height status for children with ASDs vs. unaffected siblings

For the purposes of this analysis, "very short" is defined as being equal to or below the 5th percentile for height, while "very tall" is equated with being above the 95th percentile.  (These are the same types of percentiles your pediatrician would talk about when going over your child's growth chart with you.)

In late October, about a week into data collection, we conducted an analysis which showed a much bigger difference in height between children with various ASD diagnoses than the current one does. (See Figure 3.)

Figure 3. Height Status: Children with ASDs and Unaffected Siblings -- Oct. 28, 2007Bar chart Oct 28 showing height status of children with ASDs vs unaffected siblings

When we had only 328 children with Autism, 153 children with PDD-NOS, and 142 children with Asperger's Syndrome to go on, the differences between the children with Asperger's and those with PDD-NOS, for example, looked fairly large. As we collected information from more families about additional children, more than doubling our original numbers, these differences evened out to reflect a more accurate picture.

This illustrates perfectly why it is so important to have the maximum number of people participating in this or any study. According to the laws of statistics, the more participants in a study, the more likely researchers are to arrive at findings that are not due to chance, but to a real difference in whatever is being measured. The Asperger's group that seemed extraordinarily taller than the other groups was made up of only 142 individuals, only 40 of whom were in the very tall group.

Because this group was small, statistics reported about it were less likely to be accurate. Once the number of Asperger's individuals included in the analysis grew, it was clear they were not quite so much taller than the other children as it had first appeared. Note, however, that it is still clear that more children with ASDs are above the 95th percentile for height compared with their typical peers.

(For those of you interested in statistics and probabilities, the p value for the difference in height categories -- very short, normal, very tall -- between children with ASDs and unaffected children was less than 0.001.)

Body Mass Index
Contrary to expectations that there might be a large number of children with ASDs who are very undernourished due to gastrointestinal (GI) problems, feeding problems, or pickiness regarding foods, preliminary IAN data show no major difference in the number of children with ASDs with a BMI below the 5th percentile as compared with their typical peers.

In fact, the data show that children on the autism spectrum are more likely to be obese than are typical children. ("Obese" is defined as having a BMI in the 95th percentile or above.) About 15% of typical children fall into the obese category, while 23% of children with an ASD do so.

Some of this difference may not be due to differences in body type, but to other factors affecting children with an ASD. In fact, 40% of parents who are concerned that their child is underweight, and 37% of parents who worry that their child is overweight, report that their child has a health problem or is taking medication that contributes to the weight issue. It will therefore be important for researchers to investigate the extent to which the apparent higher rate of obesity in autism is accounted for by factors such as medication side-effects.

Children with Autism, PDD-NOS, and Asperger's Syndrome all appear more likely to be obese than typical peers. (See Figure 4.)

Figure 4. Weight/BMI Status: Children with ASDs and Unaffected Siblings -- Nov. 21, 2007Bar chart showing BMI status of children with ASD vs. unaffected siblings

This is an intriguing result, with both scientific and practical implications. These data may provide support for the findings of the studies mentioned above, for example, and certainly should be taken into account by those guiding individuals with ASDs in their daily choices regarding exercise and nutrition. According to the data, children with ASDs may be at even higher risk for obesity than other children their age.

(For those of you interested in statistics and probabilities, the p value for the difference in BMI categories -- very low BMI, normal, and very high BMI -- between children with ASDs and unaffected children was 0.008.)

In the context of other recent research on body size or length in Autism, these findings are very relevant. We encourage autism researchers studying these topics to apply for access to the IAN database in order to further explore this issue.

Thank You, Families, Supporters, Researchers

We would like to thank all individuals with an ASD, family members, and researchers who have made the IAN project's success possible. Your contributions have been invaluable, and we appreciate your feedback, suggestions, and input. Please keep it coming! You can reach us at:

Spread the Word About IAN

Please remember: we have still reached relatively few of the families affected by ASDs in the United States. You can help! Spread the word about IAN to families and the professionals who work with them.

View the IAN brochure (PDF) and order free brochures to share.

Disclaimer -- Please Note: These Findings Are Preliminary

The analyses presented here by the Interactive Autism Network are preliminary. They are based on information submitted via the Internet by parents of children with autism spectrum disorders (ASDs) from the United States who choose to participate. They may not generalize to the larger population of parents of children with ASDs. The data have not been peer-reviewed -- that is, undergone evaluation by researchers expert in a particular field -- or been submitted for publication. IAN views participating families as research partners, and shares such preliminary information to thank them and demonstrate the importance of their ongoing involvement.

We encourage autism researchers investigating these topics to apply for access to the IAN database. Contact


  1. Sacco, R., Militerni, R., Frolli, A., Bravaccio, C., Gritti, A., Elia, M., Curatolo, P, Manzi, B., et al. (2007). Clinical, morphological, and biochemical correlates of head circumference in autism. Biological Psychiatry, 62, 1038-1047. View abstract
  2. Van Daalen, E., Swinkels, S.H., Dietz, C., van Engeland, H., & Buitelaar, J.K. (2007). Body length and head growth in the first year of life in autism. Pediatric Neurology, 37(5), 324-330. View abstract
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