Infection and risk of ischemic stroke: differences among stroke subtypes.

BACKGROUND AND PURPOSE: Although prior studies have demonstrated that 25% to 35% of stroke patients have had a recent infection, the role of infection as a risk factor remains unclear. Our aim was to characterize the effect of infectious/inflammatory syndromes on stroke risk. METHODS: Case-control and crossover analyses of 233 cases and 363 controls aged 21 to 89 years were performed. Cases were patients hospitalized with a first ischemic stroke at a Los Angeles, California, medical center. Controls were outpatients in the hypertension, diabetes, and general medical clinics. All subjects were administered a neurological examination, an infection/inflammation (I/I) examination, and an interview to elicit recent I/I history at baseline (within several days of stroke onset) and again approximately 2 months later. Three physicians classified subjects by the presence or absence of I/I within 1 month of the index dates, based on findings of the I/I examination, the interview report, and laboratory results. RESULTS: Infections, either total or specific, were not found more frequently in cases than controls. However, patients with a recent respiratory tract infection suffered more often from large-vessel atherothromboembolic or cardioembolic stroke than did patients without infection (48% vs 24%, P=0.07). The age- and sex-adjusted relative risk estimate for these subtypes was 1.75 (95% CI, 0.86 to 3.55). The risk was notably high for those without stroke risk factors: 4.15 (95% CI, 1.22 to 14.1) for normotensives, 2.71 (95% CI, 1.04 to 7.06) for nondiabetics, and 1.74 (95% CI, 0.74 to 4.07) for nonsmokers. Patients with a recent respiratory infection also had a more severe neurological deficit on admission than those without infection (P=0.05). CONCLUSIONS: Our results suggest that respiratory tract infection may act as a trigger and increase the risk of large-vessel and/or cardioembolic ischemic stroke, especially in those without vascular risk factors.

Sinusitis and carotid artery stroke.

The relationship between sinusitis and ischemic stroke is unexplored. The anatomic proximity between the paranasal sinuses and the internal carotid artery suggests that inflammation of the sinuses could easily extend to the intracranial vasculature. We report 4 patients with acute ischemic stroke and extensive disease of the paranasal sinuses. All patients had large vessel stroke involving the internal carotid artery territory. All patients had extensive disease of the sphenoid and other sinuses. The sinus disease was demonstrated by magnetic resonance imaging. These case report observations suggest a relationship between inflammation of the paranasal sinuses, particularly sphenoid sinusitis, and ischemic stroke.

Stroke risk in older men and women: aspirin, estrogen, exercise, vitamins, and other factors.

OBJECTIVE: To identify risk factors and preventive measures for stroke in elderly men and women. DESIGN: Observational prospective cohort study. SUBJECTS: Women (N = 8532) and men (N = 4722) between the ages of 44 and 101 (median age, 74) residing in a retirement community in southern California who had no previous history of stroke. METHODS: Upon entering the study in 1981, 1983, or 1985, study participants filled out a detailed health survey questionnaire about their medical history, exercise habits, intake of caffeinated beverages, alcohol, vitamins, and foods containing vitamins A or C, and history of smoking. Women also reported their use of estrogen replacement therapy. Cohort members were followed by periodic resurvey and by examination of death records through 1998. Age-adjusted stroke incidence rates, relative risks, and 2-sided P values were calculated. RESULTS: Between 1981 and 1998, 1211 women and 773 men were hospitalized for cerebrovascular disease. In women, risk of cerebral occlusion decreased significantly with increasing duration and recency of estrogen use. Hypertension, diabetes, heart attack, and smoking were significant stroke risk factors in both women and men. Exercise reduced stroke risk in general, and antioxidant vitamin supplements decreased the risk of cerebral occlusion. CONCLUSION: These results emphasize the role of lifestyle modification in the primary prevention of stroke and suggest that estrogen replacement therapy may be a potential preventive measure for women.