Association between physical activity and risk of stroke subtypes: the atherosclerosis risk in communities study.

BACKGROUND: The relationship between stroke subtypes and physical activity is unclear.
METHODS: Using data from 13,069 men and women aged 45-64 years who participated in the Atherosclerosis Risk in Communities Study, physical activity was assessed by self-report using the Baecke questionnaire at baseline (1987-1989). The American Heart Association's ideal cardiovascular health guidelines served as a basis for the calculation of three physical activity categories: poor, intermediate, and ideal. Stroke and its subtypes were ascertained from physician review of medical records. Multivariable adjusted hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox regression models.
RESULTS: During a median follow-up of 18.8 years, a total of 648 incident ischemic strokes occurred. Significant inverse associations were found between physical activity categories and total, total ischemic, and nonlacunar stroke in adjusted models (age, sex, race-center, education, cigarette-years). Compared with poor physical activity, the adjusted HR (95% CI) for ideal physical activity were 0.78 (0.62-0.97) for total, 0.76 (0.59-0.96) for total ischemic, 0.85 (0.51-1.40) for lacunar, 0.77 (0.47-1.27) for cardioembolic, and 0.71 (0.51-0.99) for nonlacunar stroke. Additional adjustments for waist-to-hip ratio, systolic blood pressure, antihypertensive medication, diabetes, left ventricular hypertrophy and laboratory parameters attenuated the HR. Further sex- and race-specific analyses revealed that the association was predominantly observed among males and among African-Americans.
CONCLUSION: These data suggest a tendency toward a reduced risk of total, total ischemic, and nonlacunar stroke with higher levels of physical activity.