November 13, 2017

expert reaction to study reporting an association between workplace bullying and violence, and risk of type 2 diabetes

A new study, published in Diabetologia, researchers report finding a higher risk of incident type 2 diabetes among employees exposed to bullying or violence in the workplace.

Prof. Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said:

“This is a carefully conducted study on a large number of people of working age in Scandinavia. A strength of the study is that individuals were followed up over time, which is important because diseases like type 2 diabetes take time to develop and become apparent. The study found clear evidence of an association between being bullied at work and developing type 2 diabetes. They also found evidence of an association between workplace violence and type 2 diabetes, though that evidence is rather weaker statistically.

“It’s important to understand, though, that an observational study like this cannot establish beyond doubt that it is the bullying or violence that causes people to develop diabetes. It’s possible, for instance, that people may have some characteristic that makes it more likely they will be bullied, and also, independently, makes it more likely that they will develop type 2 diabetes. The position on what causes what is particularly complex with something like bullying and diabetes. For instance, it’s plausible that drinking too much alcohol may be a cause of bullying, but it may also be a consequence of bullying, and drinking alcohol is known to increase the risk of type 2 diabetes. The researchers made extensive and praiseworthy statistical efforts to rule out the influence of several such characteristics, but such adjustments can never be perfect, and they cannot deal with characteristics that the researchers have no data on. This is why the researchers explicitly state in their report that their results “should be interpreted with caution”. They also make it clear that if in fact bullying or violence do cause diabetes risk to increase, they do not know how this process works, and they call for more research on possible ways it might work.

“Of course, even though this new study can’t show that bullying or violence cause diabetes risk to increase, and can’t say anything direct about how they might cause diabetes if indeed they do, there are plenty of other reasons to seek to reduce workplace bullying and violence.”

* ‘Workplace bullying and violence as risk factors for type 2 diabetes: a multicohort study and meta-analysis’ by Xu et al. published in Diabetologia on Monday 13^th November.

Declared interests

Prof. Kevin McConway: “I am a member of the Advisory Committee of the Science Media Centre.”