A study of 7063 people, average age 58.9 years, found that those who had high blood pressure had significantly lower memory and recognition test scores than the people with normal blood pressure (Hypertension, Dec 14, 2020;77(2):672-681). In four years of follow-up, they found that better control of high blood pressure during the study period helped to reduce the loss of mental function. Testing included analysis of memory, verbal fluency, attention, executive function, thinking and reasoning.

Normal blood pressure is defined at 120/80. An increased loss of mental function occurred in those who had systolic blood pressures 121-139 mmHg or diastolic blood pressure 81-89 mmHg and did not take medication to control their high blood pressure.
• Loss of mental function was not affected by how long they had high blood pressure, as it occurred both in people whose high blood pressure started at either a younger or older age. Having high blood pressure for a short time also was associated with loss of mental function, and those who had just a slight elevation in blood pressure suffered an increase in loss of mental function also.
• Adults with uncontrolled high blood pressure lost memory function more than those whose high blood pressure was controlled by medication.
• The authors of this study cite 59 references associating high blood pressure with impaired mental function.

Dementia Associated with Damaged Blood Vessels
Many other studies show that almost all risk factors for heart attacks are also risk factors for dementia (JAMA Neurol, Oct 1, 2017;74(10):1246-1254; Neurology, Jan 9, 2001;56(1):42-8). For example, diabetes and strokes are major risk factors for dementia (Eur Heart J, Sept 1, 2018;39(33):3119-3125). Treating causes of high blood pressure (such as diabetes, smoking, or high cholesterol) helps to reduce loss of mental function in middle aged people (J Prev Alzheimers Dis, 2019;6(1):42-49).

My Recommendations
More than 30 percent of North Americans over 85 suffer from dementia. Since dementia and heart attacks share almost all of the same risk factors and both are caused to a large degree by an inflammatory lifestyle, everyone should be tested for heart attack risk factors such as blood pressure, cholesterol, diabetes, HBA1c, overweight, and so forth. If any tests are abnormal, that should be a major stimulus to change your lifestyle immediately because at this time dementia is not reversible.