Diabetes, smoking and high blood pressure during midlife years may cause your brain to shrink. Want another reason to quit smoking or lose that gut? How about cognitive decline? “People who were obese at middle age were more likely to be in the top 25 percent of those with the fastest rate of decline in scores on tests of executive function,” according to a recent study out of University of California, Davis. Essentially if you are too heavy with bad habits like smoking or diseases like diabetes at middle-age, you will most likely have a decline in cognitive abilities like decision-making and memory.
This study determined the association between midlife vascular risk factors and brain functions. The study comprised 1,352 Caucasian community participants without dementia or severe cognitive failure. All of them were middle-aged and carried vascular risk factors including high blood pressure, diabetes, obesity, high cholesterol and smoking. Ten years after the diagnosis of their vascular abnormalities, decline in their cognitive abilities was observed. Each vascular risk factor affected one or another important brain structures. These brain structure abnormalities were closely related to the occurrence of cognitive decline.
Middle aged people are always susceptible to vascular abnormalities like hypertension, high cholesterol, obesity, diabetes, etc. Previous studies suggested that midlife vascular risk factors could be associated with risk of dementia. The current research focused on determining if midlife vascular risk factors could contribute to dementia later in life. Dementia can be predicted by neuropsychological tests of memory and aging of brain structures. There are MRI markers, like lower total brain volume, hippocampal volume, or increasing white matter hyperintensity etc., which can indicate aging of brain. A population level study was done for middle-aged people who had no dementia but carried a number of vascular abnormalities.
* 1,352 participants were selected who never had stroke, dementia or any other neural disorders.
* They were tested, for vascular risk factors at a mean age of 54 years, between 1991 and 1995. Risk factors measurement included high blood pressure, obesity (BMI), waist to hip ratio, diabetes, high cholesterol, and presence of genetic factors that may increase the chance of developing atherosclerosis or late-onset Alzheimer’s disease.
* The researchers also monitored other variables including smoking, effect of medications and levels of education.
* They were invited to take a neurophysiologic test and brain MRI at ages between 61 and 67.
* Various MRI markers like total brain volume, white matter hypersensitivity volume, temporal horn volume and hippocampal atrophy were measured. Statistical analyses were performed for finding the correlation between vascular risk factors and MRI and cognitive results.
* Hypertension and high systolic blood pressure with increase in white matter hypersensitivity volume in the brain
* Diabetes with increase in temporal horn volume
* Smoking lost brain volume overall compared to non-smokers
* People with a high waist-to-hip ratio were more likely to be in the top 25 percent of those with faster decrease in their brain volume.
* Vascular risk factors were associated with cognitive decline (both memory loss and loss in executive functions like decision making etc).
* Carriers had a more rapid decline in logical memory performance than the non-carriers.
The study has few limitations. Persons included in this study were not perfectly representative of the general population, as they were almost entirely Caucasian. They had fewer vascular risk factors than persons who were unable to undergo or declined brain MRI and neurophysiologic testing. Therefore, these findings might underestimate true associations in the general population. Also, measurement of longitudinal change in hippocampal volume in brain and correction for multiple testing were missing.
The research showed that for 1,352 participants without dementia, the mid-age related vascular risk factors affected the cognitive ability and brain structures 10 years down the line. Having hypertension, diabetes, obesity, or being a smoker damaged the brain structures and impaired the cognitive control later in life. Further, brain injury and aging were closely associated with the cognitive decline. These findings have important implications. Firstly, vascular risk factors in midlife could be taken as probable causes for future dementia. Secondly, the markers representative of brain aging and cognitive failure could be quantified at an early stage as a precautionary measure against dementia.
For More Information:
Midlife Vascular Risk Factor Exposure Accelerates Structural Brain Aging and Cognitive Decline
Publication Journal: Neurology, July 2011
By S. Debette; S. Seshadri; Department of Neurology and Center for Neuroscience, University of California at Davis
*FYI Living Lab Reports Are Summaries of the Original Research.