New research suggests that lowering blood pressure in older people could reduce their chances of dementia by 13%.
The research from Imperial College London says lowering blood pressure is already linked to fewer heart attacks and strokes and there is possibly some additional benefit associated with anti-hypertensive treatment.
The researchers say controlling blood pressure from middle-age onwards may dramatically reduce the chances of developing dementia.
A trial of elderly patients with high blood pressure to examine if those who were receiving treatment were less likely to develop any form of dementia compared with those left untreated was stopped early after the benefits of treatment in terms of reducing strokes and heart disease were so obvious it became unethical to deny them to everyone.
As many as one in four people have high blood pressure, which in many cases goes undiagnosed or untreated.
It is thought that high blood pressure may increase the risk of dementia because it can starve the brain of blood flow and the oxygen it carries.
Patients suffering this restricted blood flow are often described as having "vascular dementia" which account for approximately a quarter of dementia patients.
Although one trial found no effect of giving elderly people anti-hypertensives, the results from several trials suggest they could be helpful.
Dr. Ruth Peters, from Imperial College London says lowering blood pressure was already linked to fewer heart attacks and strokes and the new findings suggest a possible additional benefit associated with anti-hypertensive treatment.
Experts say anti-hypertensive treatment is beneficial for stroke and total mortality among the very elderly and the detection and treatment of hypertension in elderly people is important.
The Alzheimer's Society says its own research suggests that vascular dementia was six times more likely to develop in people who had high blood pressure in their 40s and 50s, and if every case was detected and treated appropriately, this would save 15,000 lives a year.
The research is published in The Lancet Neurology journal.