Yes, it's a meta study, and it focuses on young people since they are primarily the age group that use these products.
My take was that, as it said
To me, this means that the users have the other isues listed that the drinks exacerbated. That was in the first paragraph. That said they HAD those conditions, or med use, not that the drinks caused them. The drinks are thought to have made the pre-existing conditions worse. Did you read that differently?