Having high blood pressure may be associated with a lower risk of dementia in people with physical frailty, according to a study published on June 10 in Neurology, the medical journal of the American Academy of Neurology. The study found that this association was not present in people who were more robust, and that high blood pressure was linked to a higher risk of dementia among those without signs of frailty.
Researchers defined physical frailty as having three or more symptoms such as often feeling tired, little or no physical activity, slow walking speed, low grip strength, and unintentional weight loss. Pre-frailty was defined as having one or two symptoms. The study compared people with pre-frailty and frailty to those with none of these symptoms.
The research analyzed data from 6,135 participants with an average age of 75 who were followed for a median period of nine years. At the start, 334 participants met criteria for frailty, 2,376 for pre-frailty, and 2,383 were considered robust. During the follow-up period, 30% of those with frailty or pre-frailty developed dementia compared to 16% among robust individuals.
Among participants with pre-frailty or frailty, those with elevated blood pressure and hypertension developed dementia at rates of 29.5 and 41.2 cases per 1,000 person-years respectively; this compares to a rate of 42.3 cases per 1,000 person-years for those with normal blood pressure. For robust participants, elevated blood pressure and hypertension corresponded to rates of developing dementia at 13.3 and 20.2 cases per 1,000 person-years respectively; this compares to a rate of 12.6 for those with normal blood pressure.
After adjusting for factors such as age, smoking status, and diabetes that could affect dementia risk, researchers found that people showing signs of frailty who had elevated blood pressure were about one-third less likely (32%) to develop dementia than their counterparts with normal blood pressure. In contrast, robust individuals with high blood pressure were found to be nearly forty percent (39%) more likely than their peers without high blood pressure to develop dementia.
"It's exciting to think that even for people in their eighties we could help preserve people's brain health by choosing their optimal blood pressure target based on whether they have signs of frailty," Smith said. "More research is needed to determine whether managing blood pressure in this way could truly lower the risk of dementia." A limitation noted by researchers is that they did not account for when vascular conditions first appeared nor how well these conditions were managed during treatment.
