Blood pressure, haemorrhagic stroke, and ischaemic stroke: the Korean national prospective occupational cohort study

Deaths from haemorrhagic stroke declined consistently through the 20th century, but deaths from ischaemic stroke showed a rise and fall, mirroring the coronary heart disease epidemic.1 Blood pressure has also declined,2 and if blood pressure is more strongly associated with haemorrhagic stroke than with ischaemic stroke, this might contribute to the divergent trends. Previous meta-analyses have shown contradictory findings; one showed similar associations for both stroke subtypes,3 and another, of Asian studies, showed a stronger association with haemorrhagic stroke than with ischaemic stroke.4 To resolve this uncertainty, we examined the association of blood pressure with subtype of stroke in a large cohort of Korean civil servants. The Korean National Health System for public servants and teachers provides medical expenses and biennial multiphasic health examinations at which blood pressure is measured in the seated position by trained staff using a standard mercury sphygmomanometer …