Does a new study really claim that standing at work is as unhealthy as a cigarette a day? Closer inspection suggests probably not
A headline in the Independent today has proclaimed that standing at work is as unhealthy as a cigarette a day, citing a new study published in the American Journal of Epidemiology. Illustrated with a picture of a woman bent over her standing desk clutching at her back, were instructed to sit back down.
But a closer look at the research in question reveals very little to do with standing desks. In fact, the study did not look at standing desks at all. The research was conducted on a sample of 7,320 residents of Ontario, Canada, followed up for over a decade. And its findings are striking people whose job requires them to stand for long periods of time were twice as likely to contract heart disease compared to those who do jobs that predominantly involve being seated.
So should we all lower our standing desks and recover our office chairs from wherever weve stashed them? I am not going to rush to do so (at this point I should fess up and say I have used a standing desk for the past three years and I love it).
Firstly, did the researchers ask people whether they stood or sat at work? No, they did not. People were categorised by the job they did. This immediately means that if youre an office worker with a standing desk, youll be categorised as a sitter, because thats predominantly what office workers do. The supplementary table of the paper lists a number of common jobs and how they were categorised for the study. Seated jobs included truck drivers, administrative officers, secretaries, professional occupations in business services and accounting clerks. Standing jobs on the other hand included retail salespersons, cooks, food and beverage servers and machine or tool operators.
Now here we get on to the classic problem with observational epidemiology. People who work different types of jobs are going to be different in loads of ways other than their jobs, all of which might also impact on risk of heart disease. This is called confounding. The authors of the study take a number of these in to account, for example pre-existing health conditions, whether the person smokes, whether they were obese, and various others. But its very hard to be sure that youve taken all of the potential confounding factors like these in to account. There could very easily be other differences rather than just whether a person is more likely to be standing or sitting. For example how much they exercise could have a big impact. Perhaps, as one person on Twitter suggested to me, after a day on your feet youre less inclined to go for a run of an evening.
Also, as can be seen from the list of jobs theyve included in each group, there might be socio-economic differences between people who do jobs that require standing at work and those who are more likely to sit and these might be related to how good your diet is, how much disposable income you have, all things that sadly are associated with ill health. Even if you attempt to take these factors in to account in a statistical model, if youre relying on self-reported or large scale data its almost impossible to be sure youve really accounted for all the variability.
So while this study is really interesting, and might indicate that jobs where youre more likely to stand are linked to an increased risk of heart disease, personally I think theres a little more going on than simply that we should all sit down at work if we want to protect our hearts. Not to mention that this study has absolutely nothing to do with standing desks, and didnt actually ask the individuals included whether they did stand or sit at work, but inferred it from the type of job they did. Im not lowering my standing desk just yet.