I would just take it for what it is. The sample is not that small, and there can be more things included, like people who run do other things beneficial for their health. Even so, if somebody smokes and starts running, they might quit smoking because they want a better breathing pattern and it obstructs them while running. So might that be attributed to running? Dunno, I'm not an expert. But I would write this thing off.

I would also like to see data on walking. For example people who walk regularly more than x kilometers daily (those who go to work by foot) and so on. Do other activities like the elliptical have the same benefit? I shouldn't run for any prolonged period because of ankle issues, but I can happily ride the elliptical for 30-45 minutes. I suppose the answer is yes...