This headline is heavily editorialized and does not correspond with the title or findings of the study linked.

The paper's original title is 66 characters too long for HN.

The "25% higher mortality" comes from the all-cause mortality result in "Findings", which is one of the main results of the paper. The paper expresses it as a hazard ratio (HR) of 1.25 [1.10–1.42]. Hazard ratios are standard in medical research, but I wanted to summarize the main result without jargon.