A new study to investigate postural hypotension – which reduces a person's blood pressure when it rises quickly from lying down or sitting down ̵
The researchers studied more than 11,000 middle-aged adults who were tested for postural hypotension in the late 1980s. These people were screened until 2013 to see if they developed dementia or had a stroke.
Postural hypotension can have many different causes, including heart disease, and is also a side effect of high blood pressure medication. Both heart disease and hypertension are risk factors for dementia, especially vascular dementia, which is caused by decreased blood flow to the brain.
Postural Hypotension Cause and Effect
The study was conducted by researchers at Johns Hopkins Bloomberg The School of Public Health, Oregon State University, the Beth Israel Deaconess Medical Center of Harvard Medical School, and a number of other US universities a cohort study that examined data from the ARIC study that began in the 1980s. 19659003] Postural hypotension, also known as orthostatic hypotension, can lead to dizziness or fainting, as blood flow to the brain is reduced and people can injure themselves. However, the condition is more of a symptom than a disease and can be caused by a number of different conditions.
Researchers wanted to investigate whether orthostatic hypotension is possible affecting brain function and the risk of stroke or dementia in the long term, as previous studies have not given a definitive answer.
Although cohort studies are well suited to assessing the effects of risk factors over the course of a lifetime, this particular research had the caveat that it only measured postural hypotension at the beginning of the study and never again.
This means that we do not know if people who had the condition at the beginning of the study were treated successfully and it was no longer a problem. We also do not know if people who did not start the study at the beginning of the study developed it later.
The Research Methodology
The researchers used data from the ARIC study, the middle-aged people from 4 regions of the US, and monitored them over a number of years. They were initially recruited for the study from 1987 to 1989 and then invited for another four visits in the period until 2013.
For the present study, the researchers excluded individuals who had a history of heart disease, strokes or had Parkinson's disease, or who had not recorded the information the researchers needed about the study.
Orthostatic hypotension was measured only at the first assessment. People were asked to lie down for 20 minutes and take a series of blood pressure measurements before and after getting up.
People were classified as orthostatic hypotension if they had a systolic drop in blood pressure (the first, higher) (in a blood pressure reading) of at least 20 mmHg or a drop in diastolic blood pressure (the second, lower number in a blood pressure measurement) of at least 10 mmHg when they went from lying to standing.
Researchers used a number of methods to determine which study participants had dementia
In some cases, they were able to invite people to the study, in others they contacted the person or a person associated with them to ask if they had received a dementia diagnosis. In some cases, people's electronic health records were used.
They used similar methods to find out if people had a stroke.
Researchers also included other confounding factors that could influence the subsequent risk of dementia and stroke – such as age, gender, ethnicity, drinking and smoking habits and whether they had diabetes, high blood pressure or high cholesterol
The study included a total of 11,709 individuals with a mean age of 54 years enrolled.
At baseline, 552 subjects (4.7%) had orthostatic hypotension. During a follow-up period of up to 25 years, 1,068 people developed dementia and 842 a type of stroke caused by a reduction in blood flow to part of the brain
Overall, people with orthostatic hypotension had onset the study did not have a worse mental function than people they did not have after other factors were considered.
However, dementia was about 1.5-fold more frequent in those who had postural hypotension at the beginning of the study than in those who did not (Hazard Ratio [HR] 1.54, 95% Confidence Interval [CI] 1.20 to 1.97).
People with a Postural Hypothesis At the beginning of the study, the probability of having a stroke was about twice as high (HR 2.08, 95% CI 1.65 to 2.62).
The researchers found that there was a link between postural hypotension in middle age and the risk of dementia or stroke later in life, even after considering some other factors that affect one's health later in life.
However, they acknowledged that they could not explain all sorts of things could have influenced the results. For example, they were unable to monitor whether people were taking medications to treat the disease or what effect this had over time.
They said further research would be needed to understand how postural hypotension could contribute to increased risk of dementia and stroke, and ways in which any risks could be reduced.
This was a large and reasonably well conducted study that suggested a possible link between a symptom that middle-aged people can experience and their risk of developing dementia or stroke later in life. But it does not tell us why they could be connected.
Because postural hypotension was measured only at the beginning of the study, we do not know whether patients will continue to experience it over time, whether they have been successfully treated or whether they have actually been treated has developed later. We also can not say if it mattered how long someone had postural hypotension or what caused them.
Another limitation is that the study may not have found all patients with stroke or dementia. Ideally, all participants would have been directly screened by the researchers to confirm whether they had these conditions or not.
Overall, this study is likely to further investigate whether and why such a connection exists
If you have frequent dizzy spells, you should make an appointment with your family doctor as this may need to be investigated.
Andreea M. Rawlings, Stephen P. Juraschek, Gerardo Heiss, Timothy Hughes, Michelle L. Meyer, Elizabeth Selvin, A. Richey Sharrett, B. Gwen Windham, Rebecca F. Gottesman
Association of orthostatic hypotension with dementia , Stroke and Cognitive Degradation
Neurology Jul 2018, 10.1212 / WNL.0000000000006027; DOI: 10.1212 / WNL.0000000000006027
Picture above: sarah / flickr