This PhD project focusses on researching the effect of different co-morbidities on the risk for out-of-hospital cardiac arrest (OHCA) in the general population, as in populations with specific co-morbidities.  Data of the Amsterdam Resuscitation Study (ARREST), an ongoing prospective registry of all-cause OHCA in province North-Holland will be used, as well as other cohorts in this area such as the Diabetes Care System. Additionally, this PhD is part of a larger consortium ESCAPE-NET  in which other European partners participate and make their data available.