Where You Live Might Affect Your Brain, Too

Where You Live Might Affect Your Brain, Too

Jim Windell

             Brain studies continue to uncover aspects of life that affect our brains. Those aspects of daily life that can have a profound influence on our brains include exercise, smoking, alcohol consumption, trauma and even – we are now finding out – your address.

           According to a study just published in the online issue of Neurology, the medical journal of the American Academy of Neurology, where you live may predict how quickly your brain shrinks and your cognitive skills decline.

           For the study, researchers from the University of Wisconsin School of Medicine and Public Health in Madison, Wisconsin, identified 601 people from two larger studies of Wisconsin residents. Participants had an average age of 59 and no thinking or memory problems at the start of the study, although 69% had a family history of dementia. The participants were followed for 10 years.

           At the beginning of the study, participants had an initial MRI brain scan and then additional scans every three to five years. With each scan, researchers measured brain volume in areas of the brain linked to the development of Alzheimer's dementia. Participants also took thinking and memory tests every two years, including tests that measured processing speed, mental flexibility and executive function.

           Then, the researchers, led by study author Amy J. H. Kind, M.D., Ph.D., of the University of Wisconsin School of Medicine and Public Health, used the residential address of each person and a measure called the Area Deprivation Index to determine if each of the participants lived in an advantaged or disadvantaged neighborhood. The index incorporates information on the socioeconomic conditions of each neighborhood and its residents, ranking neighborhoods based on 17 indicators including income, employment, education and housing quality.

           Looking at all of the study participants, it was found that 19 people lived in the 20% most disadvantaged neighborhoods in Wisconsin while 582 people lived in the 80% of all other neighborhoods in the state. People in the first group were then matched one to four to people in the second group for race, sex, age and education and compared.

           At the start of the study, there was no difference in brain volume between people living in the most disadvantaged neighborhoods and those in other neighborhoods. However, at the end of the 10 years, researchers found brain shrinkage in areas of the brain associated with dementia in people in the most disadvantaged neighborhoods, while there was no shrinkage in the other group. Researchers also found a higher rate of decline on tests that measure risk of Alzheimer's disease.

           "Our findings suggest that increased vigilance by healthcare providers for early signs of dementia may be particularly important in this vulnerable population," said Dr. Kind. "Some possible causes of these brain changes may include air pollution, lack of access to healthy food and healthcare and stressful life events. Further research into possible social and biological pathways may help physicians, researchers and policymakers identify effective avenues for prevention and intervention in Alzheimer's disease and related dementia."

           Looking at people around the world, dementia is a major cause of illness and a devastating diagnosis. There are currently no treatments to cure the disease, which suggests that identifying possible modifiable risk factors is important. Compelling evidence exists that the social, economic, cultural and physical conditions in which humans live may affect their health. Kind and her team wanted to determine if neighborhood conditions increase the risk for the neurodegeneration and cognitive decline associated with the earliest stages of Alzheimer's disease and dementia. The results suggest that middle-age and older people living in more disadvantaged neighborhoods – areas with higher poverty levels and fewer educational and employment opportunities – had more brain shrinkage on brain scans and showed faster decline on cognitive tests than people living in neighborhoods with fewer disadvantages

           So, where you live may make a significant difference in terms of whether you experience an early deficit in cognitive skills and whether you might be subject to signs of dementia.

           To read the original journal article, find it with this reference:

Hunt, J.F.V., Vogt, N.M., Jonaitis, E.M., Buckingham, W.R., Koscik, R.L., Zuelsdorff, M.,  Clark, L.R., Gleason, C.E., Ozioma Okonkwo, M.Y., Johnson, S.C., Asthana, S., Bendlin, B.B. & Kind, A.J.H. (2021). Association of Neighborhood Context, Cognitive Decline, and Cortical Change in an Unimpaired Cohort. Neurology, 10.1212/WNL.0000000000011918 DOI: 10.1212/WNL.0000000000011918

 

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