High blood pressure in your 40s and 50s significantly affects the brain in later life

High blood pressure in your 40s and 50s significantly affects the brain in later life, researchers have found. 

A study based on brain scans from 37,000 people reveals that raised blood pressure in middle age – even at levels that wouldn’t usually require drug treatment – leads to extensive damage to the ‘white matter’ of the brain.

This can lead to dementia, stroke, physical disabilities and depression in later life.

Alarmingly, the Oxford University researchers found even small increases in blood pressure – at levels that would usually not be considered a problem – can make a major difference to the brain.

Blood pressure is expressed as two numbers, systolic – the upper number – and diastolic – the lower one.

Currently people in the UK are considered to have hypertension if blood pressure above 140/90.

The researchers found for every 10-point increase in systolic blood pressure above this level, the damage to white matter increased by about 13 per cent.

A study by University of Oxford researchers based on brain scans from 37,000 people revealed that raised blood pressure in middle age – even at levels that wouldn’t usually require drug treatment – leads to extensive damage to the ‘white matter’ of the brain (stock image)

And for every 5-point increase in diastolic blood pressure, damage increased by 11 per cent.

And the scientists also found some evidence of damage at lower blood pressure – with some people displaying brain damage at systolic levels above 120 and diastolic levels above 70.

The findings, published in the European Heart Journal, come from a study of 37,041 participants aged 40 to 69 years old, enrolled in the UK Biobank project.

The researchers examined MRI brain scans to look for ‘white matter hyperintensities’ – signs of damage to the small blood vessels in the brain.

This damage is linked to severe problems in old age, including general decline in thinking abilities and the development of dementia and mental health issues.

Researcher Dr Karolina Wartolowska, of Oxford’s Centre for Prevention of Stroke and Dementia, said: ‘Not all people develop these changes as they age, but they are present in more than 50 per cent of patients over the age of 65 and most people over the age of 80 even without high blood pressure, but it is more likely to develop with higher blood pressure and more likely to become severe.’

Among the top 10 per cent of people with the greatest brain damage, 24 per cent of this damange could be attributed to having a systolic blood pressure above 120, and 7 per cent could be attributed to having diastolic blood pressure above 70.

Dr Wartolowska said: ‘We made two important findings. Firstly, the study showed that diastolic blood pressure in people in their 40s and 50s is associated with more extensive brain damage years later.

‘This means that it is not just the systolic blood pressure, the first, higher number, but the diastolic blood pressure, the second, lower number, that is important to prevent brain tissue damage.

‘Many people may think of hypertension and stroke as diseases of older people, but our results suggest that if we would like to keep a healthy brain well into our 60s and 70s, we may have to make sure our blood pressure, including the diastolic blood pressure, stays within a healthy range when we are in our 40s and 50s.’

She added: ‘The second important finding is that any increase in blood pressure beyond the normal range is associated with a higher amount of white matter hyperintensities.

‘This suggests that even slightly elevated blood pressure before it meets the criteria for treating hypertension has a damaging effect on brain tissue.

Alarmingly, the Oxford University researchers found even small increases in blood pressure – at levels that would usually not be considered a problem – can make a major difference to the brain

‘Our results suggest that to ensure the best prevention of white matter hyperintensities in later life, control of diastolic blood pressure, in particular, may be required in early midlife, even for diastolic blood pressure below 90, whilst control of systolic blood pressure may be more important in late life.

‘The long time interval between the effects of blood pressure in midlife and the harms in late life emphasises how important it is to control blood pressure long-term, and that research has to adapt to consider the very long-term effects of often asymptomatic problems in midlife.’

Dr Richard Oakley, head of research at the Alzheimer’s Society, which part-funded the study, said: ‘High blood pressure doesn’t just affect our hearts, but our heads too.

‘Although this study didn’t look for a specific link between blood pressure and dementia, it’s an important step forward in understanding how high blood pressure is linked to changes in the brain that can increase our risk of dementia.

‘With few dementia treatments available and researchers still searching for a cure, it’s vital we do what we can to keep our minds healthy, as well as our bodies.’