Your zip code can reveal your risk of dementia

A study that recently appeared in Alzheimer’s disease and dementia: behavior and social economics of aging (Journal of the Alzheimer’s Association), found that people residing in neighborhoods characterized by greater social vulnerability, environmental inequality, and economic hardship showed measurable differences in both brain structure and activity.

“This study is consistent with other research showing that the state of the social environment in which people live can shape their brain health in profound ways,” said Timothy Hughes, MD, associate professor of gerontology and geriatrics at Wake Forest University School of Medicine and senior author.

How was the study conducted?

Researchers examined data on 679 adults who participated in the Healthy Brain Study at the Alzheimer’s Disease Research Center at Wake Forest. Each volunteer received a brain imaging and blood test designed to detect early indicators of Alzheimer’s disease and related forms of dementia.

These biological scores were then compared to three national tools that measure neighborhood conditions by zip code: the Area Deprivation Index, the Social Vulnerability Index, and the Environmental Justice Index. These indicators assess factors such as income, housing quality, exposure to pollution, and community resilience.

Clear links between neighborhood stress and brain changes

Participants living in areas with higher scores on these indicators — indicating more social and environmental disadvantages — showed greater evidence of brain changes associated with dementia risk. These effects were most pronounced among Black participants, whose communities often face higher levels of environmental, social, and economic pressures.

Brain-related signs included a thinner cerebral cortex, white matter changes associated with vascular disease, and decreased or irregular blood flow. These biological differences may contribute to memory problems and cognitive decline with age.

The permanent effect of the environment on the brain

“This study is one of the first to link a variety of place-based social factors with advanced biological markers of dementia,” said Sudarshan Krishnamurthy, MD, a sixth-year Ph.D. candidate and lead author of the study. “It shows that the conditions and environment in which people live — such as access to clean air, safe housing, nutritious food, and economic opportunity — may leave a lasting imprint on brain health.

These findings add to growing scientific evidence that where people live and the resources available to them are not merely background influences but are critical factors in understanding and treating Alzheimer’s disease and related disorders.

A call for broader political action

Krishnamurthy noted that these findings highlight the need for systemic change.

“If we truly want to improve brain health in all communities, we must look beyond individual choices and focus on the broader systems and structures that shape health at the neighborhood level.”

The study was supported by the National Institutes of Health (grants F30 AG085932 and P30 AG07294) and the American Heart Association (grant 24PRE1200264).