But those studies focus on a sedentary lifestyle and tout standing desks as a way to avoid that lifestyle. Except, standing for long periods at a standing desk isn't exactly a cure to a sedentary lifestyle. In fact, there are circulatory issues with standing in place for long periods, like blood pooling and a decrease in venous return, which can lead to all kinds of circulatory problems in the lower extremities. Anyone who has been in the military and had to stand at parade rest for two or three hours in a show of troops to honor a visiting dignitary can vouch for the issues involves in standing (and not moving around) for long periods. The real solution is to move around. Standing desks don't guarantee the user will move around any more than a sitting person, although I can see the standing person will likely be making more postural shifts during the working period.
Standing desks are worth a try for people in resonable health. Anyone with lower extremity joint issues, back issues, circulation issues, and a variety of other issues might be at higher risk with a standing desk. People with diabetes, in particular, tend to have several extremity issues, particularly with circulation in the legs, that likely would be antagonized by a standing desk. Same for obese people.
I bristle at any new thing that has a "[fill in your human activity] will shorten your life by X number of years" statement, unless it is something that presents a direct, known health challenge (like smoking). Those statements are advertising propaganda and they make me immediately distrust the product (if the marketers feel they have to resort to that kind of scare tactic). So my suggestion is to read the articles cited by various people here, consider your own personal health and health goals, and if appropriate, give a standing desk a try. But realize that standing to type is not the same as giving up a sedentary lifestyle. And also realize that someting like this does not represent a one-size-fits-all health benefit.