The disease risks associated with sitting are related to the amount of time spent in leisure sitting, NOT work sitting. 

The study done by Patel and the American Heart Association in 2010 showed

The risk of physiologic diseases like diabetes, obesity, heart disease, cancer and death from all causes are associated with non-work, leisure sitting, and the risk is even higher in the most sedentary population. The Patel study asked the question about the amount of sitting time not related to work, and the median age of that sample population was 64 years old.

Those same disease risks are not clearly related to the amount of sitting time at work. A report published the same year reviewed 43 different qualified papers that specifically measured the amount of time sitting at work, and they found no clear risk associated with the same five disease categories.

Low back pain has long been associated with work postures (Nachemson 1974, Wilke 1999) and that research has strongly influenced ergonomic chair and workstation designs

The next few slides will look more closely at posture in sitting to find better solutions