Diastolic Blood Pressure Levels and Ischemic Stroke Incidence in Older Adults With White Matter Lesions

Background. The optimal blood pressure level to minimize the risk of ischemic stroke (IS) in older adults is undetermined. Cerebral white matter lesions (WML), prevalent in older adults, may be a marker for vulnerability to IS. We aimed at determining the relationship between diastolic blood pressure (DBP) levels and IS in the presence of WML. Methods. The Cardiovascular Health Study population (N = 3,345, age >= 65 years, N = 3,345) was followed between 1989 and 2002 for IS incidence. Survival analysis included quintiles of DBP analyzed within WML levels controlling for age and cardiovascular disease. Results. DBP had no effect on IS incidence in low WML levels but had a marginally significant J-curve relationship with IS in high WML levels: the adjusted hazard ratio for IS in the lowest (< 63 mmHg) and highest (>= 80) DBP quintiles compared with the third (nadir, 69-73 mmHg) was 1.64 (95% confidence interval: 0.93-2.9) and 1.83 (95% confidence interval: 1.06-3.15), respectively. Conclusions. In older adults with low-grade WML, low DBP may not pose a risk for IS. However, in high-grade WML, IS risk may increase in DBP less than 69 mmHg but is highest more than 80 mmHg. People with high-grade WML may be at risk of IS in high and low DBP.