The Greek that is translated into English as “vain” or “in vain” in English is (back-) translated in various ways:
Guhu-Samane: “with the front teeth of their mouths they worship me” (“‘In vain’ caused puzzlement [because] why should their efforts to worship God produce no results, try as they may? [But the idiom] ‘with the front teeth of their mouths they worship me’ comes from the picture of one who is making a pretense at eating food, hence their deceit is apparent.’ Source: Ernest L. Richert in Notes on Translation December 1963: p. 4-7; reprinted in The Bible Translator 1965, p. 198ff. )
The Greek that is translated as something like “worried (or: anxious) and bothered about many things” is translated in Tzeltal as “doing all kinds of things has gone to your heart and you have difficulty because of it” (source: Reiling / Swellengrebel) and in Bariai as “You are concerned (lit. your interior is here and there) and worried (lit. you have various interiors) about very many things” (source: Bariai Back Translation).
In the German New Testament translation by Berger / Nord (publ. 1999) it is translated idiomatically as ich will dir anerkennen, dass du vor lauter Machen und Tun nicht weiß, wo dir der Kopf steht or “I will acknowledge that you don’t know where your head is because of all the doing and making.”
The term that is translated as “worried (or anxious)” in English is often translated idiomatically. Examples include “eating for oneself one’s heart” (Shona, version of 1966), “black with worry” (Chichewa), “breaking one’s head” (Sranan-Tongo), “hanging up the heart” (Bulu), “crumbling in one’s abdomen” (Western Kanjobal), “one’s stomach is rising up” (Farefare), or “one’s mind is killing one” (Navajo (Dinė)). (Source: Reiling / Swellengrebel)