i wonder about confounding variables like childhood nutrition. in a study like this height may actually be a proxy for socioeconomic status.

edit: and if i’d bothered to read the article i’d have noticed it said exactly that:

Instead, the authors favor an “early environment” explanation, such that people who grow up in healthy, constructive environments become taller, smarter, and more successful than those who grow up in impoverished, destructive environments.