Interesting discussion on impact on ADHD medication and growth.
https://chadd.org/adhd-weekly/could-your-childs-meds-affect-his-height-likely-not/
I think the general concept that taller kids have less mental health issues like schizophrenia or ADHD, could account for their better performance in the pool.
https://www.jaacap.org/article/S0890-8567(23)00185-5/fulltext