The study also identified a connection between premature birth, rapid weight gain in infancy, and autism. While there was no link found between leptin levels at birth and autism or weight gain, children with the highest leptin levels had eight times higher odds of being diagnosed with autism compared to those with the lowest levels. Additionally, children with rapid weight gain in infancy had three times higher odds of autism, although this association disappeared when controlling for prematurity.

The researchers suggest that leptin levels may serve as a potential biomarker for autism if validated in larger studies. They believe that leptin levels could be a proxy for prenatal factors related to autism and rapid weight gain in infancy. It is possible that rapid weight gain and elevated leptin are the body’s response to prematurity or an early life event. However, the role of prematurity in this association cannot be ruled out.

The study also highlighted the potential influence of obesity on the link between high leptin levels and autism. Obesity is associated with elevated leptin levels and autism, and it may be driving the observed association. The researchers emphasize the need for confirmation of these findings in children who were not born prematurely. Tracking leptin levels during infancy and childhood could provide further insight for future research.