A systematic review and meta-analyses published yesterday in The Lancet , containing data from more than 25 studies from 24 cohort studies across three continents found that those who work long hours have a higher risk of stroke as well as coronary heart disease than those working standard hours. The association is stronger for stroke when compared to coronary heart disease but both the associations fulfill many of the criteria’s for causation as per Bradford Hill Criteria- strength, consistency, temporality, dose response, reverse causation and of course plausibility !
However your boss may not trust this results and allow you to go back home at standard hours in case he decides to take into consideration that a large proportion of the unpublished individual-participant data that was used
in this study was from the IPD-Work Consortium which had done on convenience sampling. Read the full paper here (Click: Open Access)