NEW YORK: Middle-aged people with high blood pressure are three times more likely to develop a common form of dementia, the largest study of its kind has found.
Millions of people have been urged to take pills to lower blood pressure after research suggested it could prevent thousands of cases of the condition. The risk was biggest among people aged 30-50; the higher their blood pressure, the greater their chances of developing vascular dementia, scientists in Oxford and Sydney found.
About 150,000 people in Britain have vascular dementia, which is caused by problems with the blood supply to the brain. While research has found strokes could lead to the condition, the new study of millions of patients found high blood pressure alone also raised the risk.
Data from GPs on 4.3 million people, of whom 11,114 developed vascular dementia, was analysed in a study led by Kazem Rahimi of the George Institute for Global Health. Among those aged 30-50, each increase of 20mm of mercury (mmHg) in pressure when the heart was pumping blood appeared to increase the risk of vascular dementia by 62 per cent. The highest blood pressure among the middle-aged tripled the risk compared with people in the healthy range, Professor Rahimi said.
The risk fell with age, with those aged 50-70 facing a 26 per cent increase for extra 20mmHg. For those older than 70, higher blood pressure did not seem to increase risk, according to results published in the journal Stroke. Professor Rahimi said this might be because as people aged, the importance of other risks grew relative to blood pressure.