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Systolic but not diastolic hypertension may be linked to dementia risk

By Bianca Nogrady
Higher systolic blood pressure (SBP) in middle-age may be associated with an increased risk of dementia in later life, according to new data published in the European Heart Journal.

Researchers examined the association between SBP and dementia using data from 8639 participants (32.5% women) in the Whitehall II cohort study, whose BP had been measured in 1985, 1991, 1997 and 2003.

They found that individuals with an SBP of 130 mmHg or greater at age 50 years had a 38% increased risk of dementia during follow up (up to 2017) compared with those with lower SBP at the same age. The association was not seen in older individuals, nor with elevated diastolic BP in any age group.

The association was even evident in individuals with an SBP of 130 mmHg or greater at age 50 years who remained CVD free during follow up, ‘suggesting that clinical CVD does not fully account for the association between hypertension and dementia,’ the researchers wrote.

The analysis also showed that longer periods of SBP at or above 130 mmHg between ages 45 to 61 years were associated with a 29% higher risk of dementia compared with no or a shorter period of systolic hypertension.

Commenting on the findings, Professor Perminder Sachdev said there is currently some debate about the cut-off point to define systolic hypertension.

The American Heart Association recently revised down their recommendations for treatment of hypertension to 140/90 mmHg, except in individuals older than 60 years, in whom levels up to 150/90 mm/Hg should be tolerated, with CV health in mind.

'If we are going to say that for brain health the target should be more like 130 mmHg for SBP, that does certainly raise some issues for discussion,' Professor Sachdev, Scientia Professor of Neuropsychiatry at the Centre for Healthy Brain Aging at UNSW, Sydney, told Cardiology Today.

However, he stressed that further studies would be needed to more closely investigate the additional effects of systolic hypertension on brain health, and target levels for different ages also needed further clarity.

He also noted that although the study attempted to control for CVD, there may still have been silent vascular changes in the brain that were not accounted for.
Eur Heart J 2018; doi: 10.1093/eurheartj/ehy288.