Vascular risk factors such as diabetes, high blood pressure, obesity and smoking, in middle age are linked with accelerated rate of brain aging and mental decline later in life, according to a study led by the University of California (UC) Davis that was published in the journal Neurology on 2 August.

Senior author Dr Charles DeCarli, from the Department of Neurology and Center for Neuroscience, at UC Davis, who is also a member of the American Academy of Neurology told the press:

“These factors appeared to cause the brain to lose volume, to develop lesions secondary to presumed vascular injury, and also appeared to affect the brain’s ability to plan and make decisions as quickly as it had 10 years earlier.”

For the study, the researchers examined 1,352 participants without dementia who were taking part in the prospective Framingham Offspring Cohort Study.

They assessed their cardiovascular risk factors, including blood pressure, cholesterol, diabetes, smoking status and obesity in midlife (average age 54), and then looked for links with various markers of brain aging and changes in mental ability, both of which were assessed at the start of the study (baseline) and then at follow up 7 to 13 years later.

The brain aging markers were changes in white hyperintensity volume, total brain volume, temporal horn volume, which were assessed using MRI scans and the mental ability measures included a range of widely used memory and decision performance tests.

The results showed that:

  • Compared to people with normal blood pressure, high blood pressure (hypertension) in midlife was linked to accelerated white hyperintensity volume progression (these show as bright white areas on MRI scans and signify increased vascular damage, a sign of brain deterioration).
  • High blood pressure in midlife was also linked to faster decline in scores on decision tests.
  • Obesity in midlife was linked to a greater chance of being in the top 25% of participants with the greatest decline in executive function (ie with the biggest drop in scores on the decision ability tests).
  • Midlife diabetes and smoking were linked to a greater annual increase in the temporal horn volume, a “surrogate marker of hippocampal atrophy” and possible indicator of Alzheimer’s, in later life.
  • Midlife smoking also predicted a more marked decrease in total brain volume and increased risk of extensive change in white hyperintensity volume.
  • And having a larger waist-to-hip ratio was linked to a signficant decline in total brain volume.

The authors concluded that:

“Midlife hypertension, diabetes, smoking, and obesity were associated with an increased rate of progression of vascular brain injury, global and hippocampal atrophy, and decline in executive function a decade later.”

Written by Catharine Paddock, PhD