Oral contraceptives add to the risk for stroke in young women with migraines, but only in those who also have auras. Smoking intensifies their risk. Taking decongestants may also increase the risk for stroke in people with migraines. Infections Reports have indicated for some time that certain bacteria and viruses may play a role in atherosclerosis and heart disease, generally by provoking an inflammatory response in the arteries. Similar mechanisms may be at work with stroke.
Some evidence linking infections with stroke is as follows.
In two 2000 studies, chronic infection with Chlamydia pneumoniae, a non-bacterial organism that causes mild pneumonia in adults was linked with an increased risk for stroke. One of the studies reported a thickening of the inner vessel walls of the carotid arteries in patients who carried the organism. Chlamydia has also been linked to heart disease. A 1998 study found that patients hospitalized for stroke were three times more likely than patients without strokes to have recently been exposed to infections, usually mild ones in the respiratory tract. Chronic periodontal disease has been associated with an increased risk for stroke and heart disease.