Question: What is your interpretation of night shifts, as after 22 years researchers found that women who worked on rotating night shifts for more than 5 years were up to 11% more likely to die earlier compared to those who haven’t.

Mike Ambler answered on 7 Nov 2018:

Hi, good question…

Night shifts are not great for anybody – they aren’t good for the people doing them and the work done is usually not as good as it would have been if it was done during the day. Unfortunately, there is often no alternative.

It seems that there is a negative health impact for people who work night shifts, but it is important to recognise that some of the negative health effects may be caused indirectly: for example people may eat more sugary food to help get them through the night shift or they may drink more alcohol after a run of night shifts to try to help sleep during the night again, or possibly they might smoke more when workng night shifts. The studies you are describing will have tried to account for differences in these other factors that we know also contribute to the chances of dying (called confounding factors), but it is not always possible to 100% be sure that the mathematical process used to do this has worked.
However I would imagine that night shifts probably do damage your body to some extent, and this is further evidence of the importance of getting good sleep (for everybody, not just night shift workers). If working night shifts is unavoidable then the sensible thing to do is to try to sleep well the rest of the time, and to avoid doing things that will make you even less healthy like smoking or drinking too much.