People with high blood pressure are at risk for mild mental decline when older.
The prevalence of all types of cognitive impairment, including dementia, is on the rise, but knowledge of their causes and particularly their link with high blood pressure, is still evolving.
A 2013 study of the link between cardiovascular risk factors and cognitive function in a population-based cohort of 2,312 men and women aged 50–75, found that smoking and high blood pressure may be risk factors for cognitive decline, and thus potential targets for preventive and therapeutic interventions.
Cognitive tests used in the study included the Mill Hill Vocabulary Scale, auditory verbal learning test (AVLT), digit symbol test, verbal fluency test (VFT), Raven’s Progressive Matrices and the trail making test. A ‘g’ score (measure of general intelligence) was computed for each subject. Regression analysis was used to evaluate the association between relevant variables. Participants with higher diastolic blood pressure performed less well on the AVLT test and future decline was projected.
A significant amount of research has also shown that people with hypertension and diabetes in middle age are at greater risk for declining mental function when they are elderly. The study didn’t measure mental function in middle-aged people with these diseases.
However, a six-year Mayo Clinic study of 8,700 white and 2,300 black individuals did and found that high blood pressure and diabetes are associated with a decline in cognitive function (mental ability) in middle-aged and young-elderly. People with diabetes had the greatest and statistically significant decrease in their test scores. When the subjects were divided into a “younger” (age 47-57) and an “older” (age 58-70) age group, the decrease in test scores was significant for both age groups with diabetes. For those with high blood pressure, the test score declines were only significant for people aged 58 -70.
The changes were so small that they were probably unnoticed by the participants. However, the researchers concluded that their finding indicate the need for “aggressive diagnosis and treatment of high blood pressure and diabetes” given that “small, sub-clinical changes over time can result in impaired mental function later in life.”
Interestingly, an assessment of carotid artery wall thickness, smoking, elevated “bad” LDL cholesterol and use of non-steroidal anti-inflammatory drugs and central nervous system (CNS) drugs found no association with declines in mental ability.
The bottom line is that no matter how small the changes, declining mental function in older individuals with hypertension begins in middle age and accumulates over several years or decades. Treatment and prevention are therefore essential.