Abstract T MP67: Physical Activity Reduces Stroke Risk Among Women in the California Teachers Study Cohort
Background: Major modifiable stroke risk factors are well-established, yet strategies for effective prevention remain challenging. Developing stroke prevention strategies for women is critical due to: (i) the higher fatality and disability rate that women suffer compared to men, (ii) the unique risks to women such as from post-menopausal hormone therapy use, and (iiii) the aging female population. We evaluated three important modifiable stroke risk factors- obesity, hormone therapy, and physical activity, in the California Teachers Study cohort to identify potential stroke prevention strategies. Methods: The California Teachers Study comprises 133,479 women who enrolled in 1995 and have since been continuously followed. Using linked California state hospitalization data from 1996-2010, 3126 stroke events were defined as ischemic (N=2416; ICD-9 433, 434, 436) or hemorrhagic (N=710; ICD-9 430-432, excluding 432.1) and were validated by medical record review. Information about obesity, physical activity, hormone therapy, and medical history was collected at baseline and in follow-up questionnaires. Multivariable-adjusted hazards ratios and 95% confidence intervals were estimated by fitting Cox proportional hazards models with follow-up through 2010. Results: Consistent with previous reports, current post-menopausal hormone therapy use was associated with a 1.3-fold increased risk for stroke (95% CI=1.03-4.85). Moderate to strenuous physical activity in the 3 years before enrollment (but not lifetime activity) decreased stroke risk by 20% (HR=0.79, 95% CI=0.71-0.98). This decreased risk among physically active women was similar among current hormone therapy users, and appears to counteract the increased risk observed with current hormone therapy use. We found no association between obesity and stroke that was independent of diabetes. Conclusions: Recent physical activity reduces stroke risk and appears to counteract the increased risk associated with post-menopausal hormone therapy use.