About 3,000 adolescents in Texas, ages 13 to 17, were questioned between 2015 and 2019. The researchers compared the results with responses from more than 32,000 teens in the broader United States.

To me this appears garbled in the usual science journalism way, although it doesn't change the overall gist of it which seems legit. They analyzed each population separately and found significant results in both populations. Reported vaping was associated with an additional chance of asthma of something approximately like 0.1% to 3% at the 95% confidence interval among US adolescents, the exact range depending on numbers not included in the excerpt provided on Science Direct.

Edit: I initially thought the 15-19 age range, being the only one I saw mentioned in the excerpt, was the one studied. That does not appear to be the case. That complicates things in a way that makes it unclear precisely where the bounds of that confidence interval are when described in a way that quantifies the overall public health risk. Read the full study if you need more precise information.