High blood pressure linked to vascular dementia
A large UK study has found that people with high blood pressure are more likely to develop vascular dementia
Research published in the journal Stroke this summer has shown a link between high blood pressure between the ages of 30-70 and vascular dementia – the second most common type of dementia after Alzheimer’s disease.
The researchers looked at the health records of over 4 million people in the UK, making this the largest study examining the link between blood pressure and dementia. 1,114 people developed vascular dementia over a seven year period, and the higher the systolic blood pressure beyond 120mm Hg, the higher the risk of developing vascular dementia. In people aged 30-50, for every 20mmhg rise in blood pressure, their risk was increased by around a third.
Interestingly, the risk was different at different ages. High blood pressure was linked to a 62 per cent higher risk of vascular dementia in people aged 30-50, and a 26 per cent higher risk in people aged 51-70, but it had no effect in those between 71 and 90.
The researchers also looked at people who had had a stroke in the past
The researchers studied a group of 1,680 people who had had a stroke or transient ischaemic attack (TIA, or mini stroke) but no sign of dementia. Over the course of five years, 314 developed vascular dementia. They found the same thing, those with high blood pressure five or more years before their stroke or TIA were more likely to develop vascular dementia, and the link was strongest in people under 75.
Stroke and TIAs are known risk factors for vascular dementia. Importantly, the researchers found that stroke and TIAs only accounted for a third of the increased risk, indicating that high blood pressure plays an important role.
Why is this study important?
Vascular dementia affects 9.3 million people around the world. It can happen when the blood supply to the brain is reduced because the blood vessels are damaged or narrowed. While diabetes, obesity, physical inactivity, smoking and high blood pressure are among the known risk factors for dementia, we still have a lot to learn about the causes of dementia, and therefore, what we can do to prevent it.
The authors of the study suggest that lowering blood pressure, either by exercise, diet or blood medications, could reduce the risk of vascular dementia.
The authors make 3 important points
1 If the association seen is genuinely causal (meaning that high blood pressure causes vascular dementia, and this wasn’t just a chance finding), reducing blood pressure could bring about huge reductions in the number of people with vascular dementia
2 Even at older age, decreasing blood pressure is unlikely to cause problems - previous research has indicated that low blood pressure in people over 70 could be linked to dementia.
3 As only a third of people with vascular dementia had had a TIA or stroke, blood pressure appears to be an important risk factor. So reducing blood pressure in the general population as well as treating those who have experienced a TIA or strokes, could have the greatest impact.
Katharine Jenner, Chief Executive of Blood Pressure UK comments: “It is unsurprising that the things that effect the health of our hearts also affects the health of our minds. With the number of people with dementia worldwide expected to double in the next 30 years, it is reassuring to know that a public health programme to lower the nation’s blood pressure could lead to fewer people facing vascular dementia as well as cardiovascular disease in later life.
“Whatever your age, by eating well, exercising, and stopping smoking, you can reduce your risk of dementia, lower your blood pressure and reduce your risk of stroke, heart disease and other long-term conditions.“
Find out more
• Watch a video of one of the study authors talking about how the study worked and what the findings mean, plus read the press release from The George Institute for Global Health, where the research was done.
• Find information on eating healthily and exercise, which can help to lower your blood pressure, from NHS Choices.
• Find lots of low salt recipes and tips for lowering your salt intake to lower your blood pressure and reduce your risk of health problems from Consensus Action on Salt and Health.