Pressure and dementia
A long-term Whitehall II study, organized by the European Cardiology Community, showed that the presence of a slight increase in blood pressure, not exceeding the threshold of hypertension, in 50-year-old participants increased the risk of developing dementia later in life. The risk persisted even if the study participants did not suffer from other cardiovascular diseases.
Previous studies have led to the same results, but they did not clearly define the critical age, it ranged from 35 to 68 years. Unlike other studies, the current work assessed the association of high blood pressure with dementia at the ages of 50, 60 and 70.
Whitehall II participants were aged 35 to 55 at the start of the study in 1985. They measured blood pressure in 1985, 1991, 1997 and 2003. Other information was also collected: age, gender, lifestyle (for example, smoking or alcohol consumption), and socio-demographic factors.
For this article, the data of 8,639 people were evaluated, 32.5% of them were women. 385 participants had developed dementia by 2017.
Patients with systolic blood pressure of 130 mmHg or more at the age of 50 had a 45% higher risk of developing dementia than those with lower systolic blood pressure at the same age. This correlation was not apparent in people who developed high blood pressure at the age of 60 and 70; diastolic blood pressure was not associated with dementia.
The link between high blood pressure and dementia was also observed in people without cardiovascular disease during the subsequent period: the risk was 47% higher compared to people with systolic blood pressure below 130 mmHg.
The average age of dementia was 75 years.
The probability of developing dementia depends on systolic pressure (blue lines), compared with the pressure of 100 mmHg, accepted as a reference (red lines). The dotted line marks the confidence intervals. Source: article in the European Heart Journal.
The recommendations of NICE (National Institute for Health and Care Excellence), Great Britain, and the European Society of Cardiology consider the threshold for hypertension to be 140/90 mmHg. The 2017 recommendations from the American Heart Association, the American College of Cardiology and nine other health organizations lowered the threshold to 130/80 mmHg for all adults. The ideal blood pressure ranges between 90/60 mmHg and 120/80 mmHg.
The negative effects of middle-aged hypertension on brain health are due to the duration of exposure. Possible causes are associated with damage to the white matter, which contains nerve fibers, and inadequate blood supply.
The study has a number of limitations, in particular, a retrospective analysis of medical records, which could not include milder cases of dementia. In addition, the researchers could not verify whether the association of hypertension was stronger with Alzheimer's disease or vascular dementia, and do not know whether effective treatment of high blood pressure in middle age can reduce the risk of late dementia.
One of the important advantages of this study was repeated measurements of blood pressure in the same people, which made it possible to study their blood pressure for 18 years.
The work will have important implications both for specific patients and for public health across the state when developing mass preventive measures.
Article J. G Abell et al. The Association between systolic blood pressure and dementia in the Whitehall II cohort study: role of age, duration, and threshold used to define hypertension is published in the European Heart Journal.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru according to EurekAlert: Dementia risk increased in 50-year-olds with blood pressure below hypertension threshold.