Hypertension and large increases in blood pressure in midlife may be associated with brain pathologies in later life, according to a UK study of more than 500 baby boomers.

Researchers who followed up people born in 1946 found that high blood pressure (140/90 mm Hg or higher) may lead to reductions in brain volume and higher levels of white matter hyperintensities within the brain.

But their study, published in Lancet Neurology found no link between high blood pressure and reduced cognition or the build-up of beta-amyloid plaques.

The researchers from University College London measured overall brain volume at about 70 years of age, along with the volume of the hippocampus, the extent of white matter brain lesions, amount of beta-amyloid plaques, and cognitive capabilities in 502 participants from the Insight 46 birth cohort (born in Britain in 1946) who had BP measured at the ages of 36, 43, 53, 60-64, and 69 years old.

In the cognitively normal individuals, having 10mmHg higher systolic or diastolic blood pressure when aged between 43 and 53 was associated with about 7% and 15% more white matter lesions, respectively, at age 70. Having a 10mmHg higher diastolic blood pressure aged 43 was associated with having a 6.9mL smaller brain at about age 70.

There was however no evidence that blood pressure affected cognition or the build-up of beta-amyloid plaques. This suggested that associations between midlife blood pressure and late-life brain health are unlikely to be occurring through the build-up of beta-amyloid.

The study investigators said their findings suggested that the fourth to sixth decades of life could be a sensitive phase when higher blood pressure and increases in blood pressure have a particular impact on the future health of the brain. Therefore, routine blood pressure measurement may need to start at, or before, 40 years old, and that different approaches to blood pressure change may be needed at different ages, they said.

“We found that higher and rising blood pressure between the ages of 36 and 53 had the strongest associations with smaller brain volume and increases in white matter brain lesions in later life,” said lead author Professor Jonathan Schott of University College London.

“We speculate that these changes may, over time, result in a decline in brain function for example impairments in thinking and behaviour, so making the case for targeting blood pressure in mid-life, if not earlier”

In a linked commentary, Dr Lenore J Launer of the National Institute on Ageing, NIH, Bethesda, USA, said the simple association between blood pressure and cognitive-related brain pathology was unlikely to be a chance finding.

“Millions of individuals have unhealthy blood pressure. Immediate attention should be given to efforts to control blood pressure through clinical services and public health interventions, and to alleviate the barriers to delivery and uptake of these messages,” he wrote.