Reducing high blood pressure significantly lowers the risk of dementia and cognitive impairment, a randomised controlled study has shown.
A study in rural China of almost 34,000 people aged over 40 with uncontrolled hypertension showed significantly lower rates of all cause dementia in those who had taken part in a blood pressure-lowering programme.
The researchers studied the difference over four years amongst 163 villages where community healthcare providers provided antihypertensive medications to hit targets of 130/80 mmHg with 163 villages where residents received normal care.
Their findings highlight the potential importance of widespread adoption of more intensive blood pressure control among patients with hypertension to reduce the global disease burden of dementia.
Writing in Nature Medicine, the team noted that previous research has found that people with untreated hypertension have a 42% greater risk of developing dementia in their lifetime.
But no randomised controlled trial to date has tested the effect antihypertensive medications on the risk of dementia as a primary endpoint, they said.
In the intervention group, 17,407 patients received antihypertensive medication as well as health coaching on home blood pressure monitoring, lifestyle changes (including weight loss, dietary sodium reduction and alcohol reduction) and medication adherence.
Those in the control group were trained in blood pressure management and had their blood pressure measured in a healthcare setting.
Over 48 months, those in the BP lowering group had overall better blood pressure control, with more patients reaching target levels, than the control group.
Intensive blood pressure management substantially reduced the risk of all-cause dementia by 15% and that of cognitive impairment by 16%, the researchers found.
Several UK experts said the findings were an important reminder on the importance of blood pressure control.
Professor Sir Mark Caulfield, vice principal for Health for Queen Mary’s Faculty of Medicine and Dentistry said: ‘There have been prior studies suggesting correlation of blood pressure level and dementia risk – especially vascular dementia – but this is a very emphatic outcome of a trial.
‘The trial is in a Chinese population so some people might say it isn’t generalisable, but we know from other research that the correlation of blood pressure level with adverse outcomes is consistent across populations.’
Professor Masud Husain, professor of neurology at University of Oxford, said: ‘This is a landmark study with a very large sample size and a robust effect. It’s a wake-up call to treat high blood pressure intensively, not just to protect the heart but also the brain.”
‘Remarkably, within just four years, there was a significant reduction in the incidence of dementia by aggressively treating raised blood pressure.
‘Although many patients and their GPs understand how important it is to treat blood pressure, they might not appreciate what a risk it poses for developing dementia.’
It comes as Pulse has revealed that GPs in parts of England are being subjected to rationing of NHS Health Check funding, meaning not all eligible patients can be called forward.
Suspect clinicians in China might have access to techniques for ensuring compliance that are not generally available in the UK (yet).