Study designBMJ 2009; 338 doi: http://dx.doi.org/10.1136/bmj.a3191 (Published 08 January 2009) Cite this as: BMJ 2009;338:a3191
- John Fletcher, clinical epidemiologist
- 1BMJ, London WC1H 9JR
A neurologist wanted to study the risk of stroke and transient ischaemic attack in people with a diagnosis of migraine. From her headache clinic she selected cases of migraine and controls without migraine. She collected stroke and transient ischaemic attack outcomes by writing to all subjects and their general practitioners five years …
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