High blood pressure, diabetes and obesity each linked to unhealthy brains
11 Mar 2019
Factors that influence the health of our blood vessels, such as smoking, high blood pressure, obesity and diabetes are linked to less healthy brains, according to new research part-funded by the MRC.
The study, published in the European Heart Journal, examined the associations between seven vascular risk factors and differences in the structures of parts of the brain. The strongest links were with areas of the brain known to be responsible for our more complex thinking skills, and which deteriorate during the development of Alzheimer’s disease and dementia.
The researchers examined MRI scans of the brains of 9,772 people, aged between 44 and 79, who were enrolled in the UK Biobank study – one of the largest groups of people from the general population to have data available on brain imaging as well as general health and medical information.
The researchers looked for associations between brain structure and one or more vascular risk factors, which included smoking, high blood pressure, high pulse pressure, diabetes, high cholesterol levels, and obesity as measured by body mass index (BMI) and waist-hip ratio. These have all been linked to complications with the blood supply to the brain, potentially leading to reduced blood flow and the abnormal changes seen in Alzheimer’s disease.
They found that, with the exception of high cholesterol levels, all of the other vascular risk factors were linked to greater brain shrinkage, less grey matter (tissue found mainly on the surface of the brain) and less healthy white matter (tissue in deeper parts of the brain). The more vascular risk factors a person had, the poorer was their brain health.
Lead author, Dr Simon Cox, a senior research associate at the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh, said: “We found that higher vascular risk is linked to worse brain structure, even in adults who were otherwise healthy. These links were just as strong for people in middle-age as they were for those in later life, and the addition of each risk factor increased the size of the association with worse brain health.”
Smoking, high blood pressure and diabetes were the three vascular risk factors that showed the most consistent associations across all types of brain tissue types measured.
Dr Cox said: “We compared people with the most vascular risk factors with those who had none, matching them for head size, age and sex. We found that, on average, those with the highest vascular risk had around 18ml, or nearly 3%, less volume of grey matter, and one-and-a-half times the damage to their white matter – the brain’s connective tissue – compared to people who had the lowest risk.”
Dr Ivan Pavlov, programme manager of multimorbidity at the MRC, said: “This research underscores the fact that risk factors for poor physical health, in particular, cardiovascular, can also negatively impact on our brains. Although the study did not address cognitive functions, and the structural changes were small in magnitude, it indicates that keeping blood vessels in good shape and healthy lifestyle choices may have benefits beyond one’s heart and could slow down changes commonly associated with brain ageing.”
Now the researchers plan to measure the links between vascular risk factors and thinking skills in the UK Biobank participants and in other groups too. In addition, they are following older people, and carrying out multiple scans and tests of thinking skills.