There is a statistical link between long work hours and stroke risk. Working more than 55 hours per week is associated with a one-third increased risk of stroke compared to working 35 to 40 hours per week. This is the result of an international meta-analysis that summarised and reviewed 25 studies on this topic, which were presented in "The Lancet".
Scientists under the leadership of Mika Kivimaeki from University College London (United Kingdom) examined the effects of longer working hours on the frequency of cardiovascular diseases and strokes. The meta-analysis of coronary heart disease included data for about 604,000 study participants, and the meta-analysis of stroke comprised data for almost 529,000 women and men; total follow-up was 5.1 million person-years, respectively 3.8 million person-years.
The negative effect of longer working hours is striking - particularly in terms of stroke risk. Here, the researchers recorded a dose-response association: compared with people who worked 35 to 40 hours per week, those working between 41 and 48 hours had a ten per cent higher risk of stroke (statistically non-significant). In the group of those working 49 to 54 hours per week, the risk of stroke increased by 27 per cent (statistically significant). A one-third increase in stroke rates was found among people working 55 hours and more per week (statistically highly significant).
In the group working the longest hours, a more modest 13 per cent increase in the risk of developing coronary heart disease was found. Compared to people working 35 to 40 hours per week the difference was not significant.
Univadis
