They are associated, but risks are low and surmountable

Migraine and ischaemic stroke are both common conditions. It is hardly surprising, therefore, that the two can coexist in the same patient—but does a causal relation exist? The meta-analysis by Etminan et al in this issue provides further evidence that it does.1 Previous work showed no increase in the risk of haemorrhagic stroke in people with migraine.2

The increased relative risks reported by Etminan et al were 1.8 in migraine without aura, 2.3 in migraine with aura, and 8.7 in women with migraine who are taking the oral contraceptive pill. These figures may not be accurate because their meta-analysis has several problems: similar populations were not included; case-control studies are vulnerable to recall bias; control for confounding risk factors such as family history, smoking, diabetes, hypertension, and common treatments may not have been uniform; high risk patients with migrainous symptoms due to other conditions were not excluded; uncertainty existed in some studies about …