Writing in the journal Clinical Endocrinology, Dr. James Mills of the NICHD and colleagues said they compared the height, weight, head circumference and levels of growth-related hormones to growth and maturation in 71 boys with autism to a group of 59 healthy boys.
The boys with autism had higher levels of two hormones that directly regulate growth — insulin-like growth factor-1 and IGF-2. The boys also had higher levels of hormones that indirectly affect growth.
The researchers did not measure the boys’ levels of human growth hormone, which for technical reasons is difficult to evaluate.
The boys with autism and those with autism spectrum disorders had a greater head circumference on average, weighed more and had a higher body mass index than the other boys, although there was no difference in height between the two groups of boys.