The First-Ever Study on OH and Dementia
Researchers from the University of California, San Francisco were interested in whether OH affected the risk of dementia, so they studied 2,131 cognitively healthy American men and women between the ages of 70 and 79. Participants had their blood pressure assessed sitting and standing at the start of the study and then three more times, after one year, three years and five years. A diagnosis of OH was made if the systolic (top) reading fell by 15 or more points or the diastolic (bottom) reading fell by seven or more points for at least one out of the three visits. To monitor for dementia, researchers also carried out cognitive testing over a 12-year-period. This marks the first-time dementia risk has been assessed by looking at changes in postural blood pressure over a long period of time. By the end of the study, about one person in seven was diagnosed with OH. That goes to show how alarmingly common this problem is. Out of that group, for nine percent, OH affected the systolic reading and for 6.2 percent it affected the diastolic. The percentage of people who developed dementia was 21.7 percent.Dementia Risk Shot Up by 37 Percent
After adjusting the findings for many factors that could skew the results -- such as demographics, antihypertensive drugs, cerebrovascular disease, diabetes, depressive symptoms, smoking, alcohol, body mass index and genetic factors -- the results were jarring. The researchers found that systolic OH, but not diastolic OH, was linked to a 37 percent greater risk of dementia. First author of the study, Dr. Laure Rouch, said, "it’s possible that controlling these blood pressure drops could be a promising way to help preserve people’s thinking and memory skills as they age." The research begs the question, why is OH linked to dementia? The study didn’t provide an answer. However, Dr. Rouch and her team speculate that repeated short incidences of oxygen and nutrient deprivation to the brain may cause neuroinflammation, oxidative stress and damage to the capillaries or micro blood vessels. "This cerebral microcirculatory dysfunction could, in turn, influence the integrity of the blood-brain barrier, which is the major system to remove potentially vasculotoxic and neurotoxic molecules from the central nervous system,” explains Dr. Rouch. "Previous research has shown that a dysfunctional blood-brain barrier could promote amyloid beta accumulation, for instance, as a result of altered clearance and permeability." Dr. Rouch hopes these findings will alert clinicians to the importance of monitoring orthostatic blood pressure in older adults.My Takeaway
This research is something we can put to work in our own lives, in my opinion. Next time you’re in your doctor’s office for a physical, have him or her check your blood pressure while you’re sitting, and then while you’re standing to get a good postural blood pressure reading. You could also test yourself at home with your blood pressure monitoring equipment. If your systolic number falls 15 points or more, then you should pay close attention to your memory and cognition. The research also brings to mind the importance of exercise. If you keep your body moving on a regular basis, you’ll help keep blood flowing to your brain and you’ll be less likely to suffer from poor nutrient and oxygen flow to the brain.