High blood pressure linked to Alzheimer’s disease

High blood pressure in later life, and a faster decline in systolic blood pressure (SBP), may trigger brain infarcts, Neurology recently reported. Raised SBP may also increase the number of neurofibrillary tangles, a hallmark of Alzheimer’s disease.

Researchers followed 1,288 people for a mean of eight years before their deaths at an average age of 88.6 years. At baseline, 87 per cent had a history of antihypertensive use, 66 per cent had a history of hypertension and 48 per cent had at least one brain infarct.

High blood pressure increased the likelihood of brain infarcts. For example, a person with SBP that was one standard deviation (SD) above the mean (134-147mmHg) was 46 per cent more likely to show one or more infarct, and 46 and 36 per cent more likely to show gross (large) infarcts and microinfarcts respectively. An increase by one SD was equivalent to nine years of brain ageing on the risk of having one or more brain infarcts.

An increase of one SD from the mean diastolic blood pressure (71- 79mmHg) was associated with a 28 per cent increased risk of at least one infarct, as well as 22 and 25 per cent increases in the risk of gross infarcts and microinfarcts respectively.

A faster decline in SBP also increased the likelihood of one or more brain infarcts. Further studies are needed, but reduced cerebral perfusion might predispose to some infarcts. Higher mean SBP was associated with a greater number of neurofibrillary tangles, but not plaques or other pathological changes. Study author Zoe Arvanitakis of the Rush Alzheimer’s Disease Center, Chicago, said that the findings are difficult to interpret and will need more research. “

While our findings may eventually have important public health implications for blood pressure recommendations for older people, further studies will be needed to confirm and expand on our findings before any such recommendations can be made,” she said.



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