Philadelphia, PA - Higher diastolic blood pressure (DBP), but not systolic blood pressure (SBP), can impair cognitive status in individuals without a prior history of stroke or transient ischemic attack (TIA), according to results of a large study reported in the August 25, 2009 issue of Neurology [1].
"The present study indicates that elevated [DBP] levels are linearly and cross-sectionally associated with a higher likelihood of impaired cognitive status. If this association is causally established in future longitudinal studies, reducing elevated BP levels may result in reducing the incidence of dementia," lead author Dr Geogios Tsivgoulis (University of Alabama at Birmingham) said in an interview.
The study authors write that the prevalence of dementia is estimated at approximately 8% and the prevalence of hypertension is approximately 65% among individuals aged 65 years or older. While the relationship between blood pressure, cognitive function, and dementia has received a lot of attention in recent years, the findings have varied greatly.
In this study, the investigators sought to evaluate the cross-sectional relationship of blood-pressure components (SBP, DBP, and pulse pressure) with cognitive impairment after adjusting for potential confounders.
Tsivgoulis and his team looked at data from 19 836 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national, population-based, longitudinal cohort evaluating stroke risk.
The subset of patients studied by Tsivgoulis et al had no prior history of stroke or TIA and completed baseline home physical evaluations.
Intriguing findings
Study results showed that higher DBP levels were associated with impaired cognitive status after adjustment for demographic and environmental characteristics, risk factors, depressive symptoms, and antihypertensive medications. An increment of 10 mm Hg in DBP was associated with 7% (95% CI 1%-14%, p=0.0275) higher odds of cognitive impairment.
However, no independent association was identified between impaired cognitive status and SBP (odds ratio 1.02, 95% CI 0.99-1.06) or pulse pressure (OR 0.99, 95% CI 0.95-1.04).
"We attributed these intriguing findings to a potential association between diastolic hypertension and accelerated stiffening of cerebral small vessels that are profoundly affected by DBP," Tsivgoulis commented.
The results showed no evidence of nonlinear relationships between any of the blood-pressure components and impaired cognitive status; no interaction between age and the relationship of impaired cognitive status with SBP, DBP, or pulse pressure; and no interaction between race and the relationship of impaired cognitive status with SBP, DBP, or pulse-pressure levels.
"Our study showed that higher DBP levels were independently related to a higher likelihood of impaired cognitive status in a large national sample that was nearly balanced with respect to race and gender," said Tsivgoulis. However, he added, the linear, cross-sectional association needs to be confirmed in a longitudinal analysis.
Laying the groundwork
Dr John Hart (University of Texas, Dallas), who was not involved with the study, said that it "is another step in laying the groundwork for some things we're noticing about the vascular effects on cognitive decline with aging."
In the future, Hart said that he'd like to see a big, definitive, prospective, longitudinal study "with a rich set of cognitive measures and some neuroimaging to correlate with the findings.
"I think this study reaffirms the fact that you want to do your best to screen and treat for vascular risk factors in individuals, not just those that people normally think of [for heart disease], but also for strokes or vascular changes that might affect cognition in the brain. It just adds another piece of evidence that says that we should all be treating these risk factors aggressively to prevent long-term effects down the road. That's such a straightforward, easy thing to do, and it lets you see real differences at the end of the game."Philadelphia, PA - Higher diastolic blood pressure (DBP), but not systolic blood pressure (SBP), can impair cognitive status in individuals without a prior history of stroke or transient ischemic attack (TIA), according to results of a large study reported in the August 25, 2009 issue of Neurology [1].
"The present study indicates that elevated [DBP] levels are linearly and cross-sectionally associated with a higher likelihood of impaired cognitive status. If this association is causally established in future longitudinal studies, reducing elevated BP levels may result in reducing the incidence of dementia," lead author Dr Geogios Tsivgoulis (University of Alabama at Birmingham) said in an interview.
The study authors write that the prevalence of dementia is estimated at approximately 8% and the prevalence of hypertension is approximately 65% among individuals aged 65 years or older. While the relationship between blood pressure, cognitive function, and dementia has received a lot of attention in recent years, the findings have varied greatly.
In this study, the investigators sought to evaluate the cross-sectional relationship of blood-pressure components (SBP, DBP, and pulse pressure) with cognitive impairment after adjusting for potential confounders.
Tsivgoulis and his team looked at data from 19 836 participants in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a national, population-based, longitudinal cohort evaluating stroke risk.
The subset of patients studied by Tsivgoulis et al had no prior history of stroke or TIA and completed baseline home physical evaluations.
Intriguing findings
Study results showed that higher DBP levels were associated with impaired cognitive status after adjustment for demographic and environmental characteristics, risk factors, depressive symptoms, and antihypertensive medications. An increment of 10 mm Hg in DBP was associated with 7% (95% CI 1%-14%, p=0.0275) higher odds of cognitive impairment.
However, no independent association was identified between impaired cognitive status and SBP (odds ratio 1.02, 95% CI 0.99-1.06) or pulse pressure (OR 0.99, 95% CI 0.95-1.04).
"We attributed these intriguing findings to a potential association between diastolic hypertension and accelerated stiffening of cerebral small vessels that are profoundly affected by DBP," Tsivgoulis commented.
The results showed no evidence of nonlinear relationships between any of the blood-pressure components and impaired cognitive status; no interaction between age and the relationship of impaired cognitive status with SBP, DBP, or pulse pressure; and no interaction between race and the relationship of impaired cognitive status with SBP, DBP, or pulse-pressure levels.
"Our study showed that higher DBP levels were independently related to a higher likelihood of impaired cognitive status in a large national sample that was nearly balanced with respect to race and gender," said Tsivgoulis. However, he added, the linear, cross-sectional association needs to be confirmed in a longitudinal analysis.
Laying the groundwork
Dr John Hart (University of Texas, Dallas), who was not involved with the study, said that it "is another step in laying the groundwork for some things we're noticing about the vascular effects on cognitive decline with aging."
In the future, Hart said that he'd like to see a big, definitive, prospective, longitudinal study "with a rich set of cognitive measures and some neuroimaging to correlate with the findings.
"I think this study reaffirms the fact that you want to do your best to screen and treat for vascular risk factors in individuals, not just those that people normally think of [for heart disease], but also for strokes or vascular changes that might affect cognition in the brain. It just adds another piece of evidence that says that we should all be treating these risk factors aggressively to prevent long-term effects down the road. That's such a straightforward, easy thing to do, and it lets you see real differences at the end of the game."
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