In this case, I find it likely there's an underlying common cause. I suspect the real culprit is the overall activity level of the person, and sitting is just a part of that.
What's particularly interesting about recent research is the revelation that sitting for extended periods of time does significant damage to human health that cannot be undone by exercising. Sitting for several hours each day is bad for you, like smoking is bad for you, regardless of whether you do healthful activities, too.
Which is why this story keeps coming up. Sitting for 8-10 hours a day is NOT countered by going to the gym for another 2.
The study, as far as I can tell from CNN's reporting, does not support this conclusion. The relevant data: In particular, the American Cancer Society study finds that women who sit for more than six hours a day were about 40% more likely to die during the course of the study than those who sat fewer than three hours per day. Men were about 20% more likely to die.
They make no mention of also measuring overall activity levels, which you would need to do to account for that potential confounding common cause. Perhaps the real study did this, but CNN does not tell us, nor do they tell us which study this actually was so we can look for ourselves. I suspect the real study's conclusions are not as strong as this reporting on it.
Why is your quote from the article meaningful while mine is not? It's right there!
"What's particularly interesting about recent research is the revelation that sitting for extended periods of time does significant damage to human health that cannot be undone by exercising."
Crappy reporting on science as usual, but it says it right there "recent research" + "revelation" + "sitting for extended periods" + "damage" + "cannot be undone by exercising."
Because I find it less likely for the reporter to get basic facts wrong. Conclusions are more subtle, and I don't know if it's the reporter's own conclusions, the reporter's interpretation of the conclusions from the original study, or an almost direct lift from the conclusions from the original study. Since the data the reporter does present does not support the conclusions he presents, I remain skeptical of them.
Your back and leg muscles are much more active while standing than sitting. You are actively burning calories, building bone mass, building muscle mass. Despite tightening my belt a notch over the last year of having a standing desk, I have stayed the same weight with only marginal additional exercise.
Your experience is not inconsistent with my hypothesis: your overal activity level increased. A counter-example would be someone who is active on a regular basis, sits for many hours in the other parts of the day, and still suffers from the same health problems as someone who is inactive.
"Correlation does not imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'."