Bone and muscle strength deficits in male children with autism spectrum disorder

PURPOSE: We compared bone and muscle strength and related factors between children with autism spectrum disorder (ASD) and typically developing children (TDC). METHODS: We included 15 male children with ASD (mean age: 10.3, SD: 2.7 years) and 45 TDC (11.4, 1.8), matched for sex, age, maturity, height and body mass. We used pQCT to assess bone strength, area, and content at the distal and shaft sites of the radius and tibia, as well as muscle area at the forearm and lower leg. We measured grip strength and long jump distance and recorded daily physical activity (PA) and vitamin D, calcium, and protein intakes. We used site-specific multivariate analyses of covariance to compare bone outcomes, adjusting for muscle area. We compared PA and nutrient intakes using multivariate analyses, and muscle area and performance outcomes using analysis of variance. RESULTS: Children with ASD had 13-31% lower bone strength, area, and content at the shaft sites of the radius and tibia, and distal tibia. They also had 26-33% lower grip strength and long jump distances, spent 76% more daily time in light PA, and accumulated 67% fewer bone impact counts compared with TDC. CONCLUSION: We report deficits in bone strength and content accompanied by lower muscle strength performance and fewer bone-impacting activities in male children with ASD. Future research should determine whether lower muscle strength and reduced bone-loading exposure contribute to bone deficits and may serve as targets to optimize bone development.