Can sitting all day lead to an early death, is sitting an independent risk factor for heart disease

I should have found the news link to send you. Take a read and let me know what you think:

Why your desk job is slowly killing you? http://www.msnbc.msn.com/id/39523298/ns/health-mens_health/t/why-your-desk-job-slowly-killing-you/
- Dr. Mark Hamilton, who is a professor and physiologist at the Baton Rouge Pennington Biomedical Research Center, says that a more and more research is showing that time spent exercising and time spent sitting on your butt are completely independent risk factors for heart-disease. New evidence seems to suggest that there is a strong correlation between the more hours spent sitting, the greater your change of dying prematurely, regardless of how much time you spend exercising, or how lean your body is. That's right: Joe's six-pack apps can't protect him from spending too much time in his chair.