Staying hydrated is linked to lower risk for disease, faster aging, early death

From the "a news release" link:

"Using health data gathered from 11,255 adults over a 30-year period, researchers analyzed links between serum sodium levels – which go up when fluid intake goes down – and various indicators of health. They found that adults with serum sodium levels at the higher end of a normal range were more likely to develop chronic conditions and show signs of advanced biological aging than those with serum sodium levels in the medium ranges. Adults with higher levels were also more likely to die at a younger age. "

Um. Clearly that's correlation.

I don't see how the submission title is consistent with the article:

"Staying hydrated is linked to ... faster aging, early death"

The article makes the opposite claim.