Migraine with aura and stroke

Is everyone who gets migraines at an increased risk of a stroke?
This large survey and editorial say:

• Only the quarter of migraine sufferers who get an aura are at increased risk of stroke
• Migraine with aura doubles a person's risk of having a stroke
• Migraine is also associated with an increased risk of transient ischaemic attacks and angina. It isn't clear whether this is true for all migraine sufferers or only those with aura
• Migraine without aura isn't associated with an increased risk of stroke
• Aura is a transient neurological disturbance before or during the headache
• Sensitivity to light, visual blurring, and fatigue are common accompaniments to migraine but should not be confused with aura
• People who have migraine with aura should have their other risk factors treated (smoking, blood pressure, cholesterol, and blood glucose)

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Source: BMJ 2009;339:b4380