[joe_the_user]

This mis-characterizes the article. "Correlation is not causation" can be said about anything. The article has a number of specific findings which weaken the original finding.

Just about every strong and weak scientific finding involves correlation. "Correlation is not causation" comes into play most strongly when a correlation seems assign causation to something with no clear underlying physical mechanism - leap years and stock market behavior, etc. But one could imagine a number of plausible physical mechanism whereby sitting could be back bad for one. That still doesn't prove it but it different lines of reasoning could appropriate.

[pessimizer]

But the obvious correlation is that of the million situations that could cause someone to sit more, more of them lead to early death than extended life. For example, asthma, arteriosclerosis, and obesity are known to lead to both situations.

When a study comes out that exhaustively controls for at least all of known factors that cause both situations being correlated, give me a call.