Physical Exercise and Bone Fracture Rates in North American Children with Autism Spectrum Disorder

Background: Physical exercise has been shown to improve motor skills, physical fitness and social skills in youth with autism. However, children with autism may not exercise as much and have lower bone density than their typically developing peers.

Objectives: The study examined the frequency of physical exercise and bone fracture rates as well as underlying factors in children with Autism Spectrum Disorder (ASD).

Methods: We compared the reported frequency of recent physical exercise activity between children with ASD in the Autism Treatment Network (ATN) sample and national data derived from the National Survey of Children’s Health (NSCH). In addition, we compared lifetime bone fracture rates in children with ASD in the ATN sample with relevant prior publications. Furthermore, we examined the contribution of demographic, child, and family (parent) factors on reported frequency of recent physical exercise activity and lifetime prevalence of bone fractures in children with autism.

Results: The results confirmed that the overall distribution of physical exercise rates were significantly different between the ATN and NSCH samples for 6-11 year old males (p< 0.001). Compared to the NSCH sample in the male 6-11 year old group, children with autism tended to exercise less often. A similar effect was seen across other age groups and in females, which was not statistically significant. Although the fracture prevalence rate increased by age group, no differences were found between children with autism and the general population.

Conclusions: The findings confirm that 6-11 year old boys with autism exercise less frequently compared to the NSCH sample. Although older children and girls with autism showed decreased frequencies in physical exercise compared to NSCH, the findings did not reach statistical significance. Fracture rates depend on both bone density and nature and frequency of physical activity. Fracture rates for children with autism increased by age group, similar to reported fracture rates in the general population, despite a lower frequency of exercise in children with autism. Demographic, child, and family (parent) factors did not contribute to the findings in a meaningful way. Future studies should include more heterogeneous samples as well as objective measures of physical exercise activity and bone density assessments to better understand predictors of physical exercise and bone fracture rates in this population.