Head size does not appear to impact a child’s likelihood of developing autism, a new study suggests. (Thinkstock)

There’s long been talk of a connection between autism risk and infant head size, but a large new study suggests that no such link exists.

In looking at data on nearly 700 children collected at a dozen sites across the United States and Canada, researchers said they found no evidence that large head size serves as a predictor of autism.

For the study, data was collected on 442 children considered to be high risk because they had an older sibling with autism as well as 253 kids with no family history of the developmental disorder. Researchers tracked the children’s growth between the ages of 6 months and 3 years, at which point the kids in the high-risk group were evaluated for an autism diagnosis.

Ultimately, 77 children in the high-risk group were diagnosed with autism and 32 had developmental delay. However, no differences were seen in head growth or height between children who developed autism and those who did not, according to findings published online this month in the Journal of the American Academy of Child and Adolescent Psychiatry.

“There are no significant differences in the overall model comparing head growth between (high-risk) infants (regardless of outcome) and (low-risk) controls in the first three years of life,” the researchers wrote in their findings, adding that “head growth was largely uninformative as an ASD risk marker.”

Though head growth was not associated with autism in the study, the researchers said the current findings do not include sufficient data to consider the role that accelerated brain growth may play as a predictor of autism.