Study links mid-density neighborhoods to higher dementia death rates

A study published today in JAMA Network Open reports the highest dementia mortality rates in neighborhoods with population densities between 5,000 and 10,000 people per square mile. These areas, described as the "missing middle," include the outer edges of several major U.S. cities such as Los Angeles, Minneapolis, Baltimore, Pittsburgh, and Milwaukee.

Denser city centers and lower-density rural regions recorded lower rates. Researchers noted that dementia is a symptom of underlying diseases such as Alzheimer’s that impair vital functions including heart rate and breathing.

Access and environment factors A geriatrician and director of research at the Northwell Institute for Healthy Aging stated that suburban neighborhoods often combine limited access to medical services with poorer air quality and fewer opportunities for physical activity.

The same physician said residents in these areas may miss appointments, receive delayed diagnoses, and experience greater social isolation, both established risk factors for cognitive decline. Denser urban neighborhoods typically provide more primary care offices, pharmacies, groceries, and public transportation.

Rural areas tend to offer cleaner air and more space for outdoor activity.

Potential interventions The study estimates that more than 65,000 dementia deaths could be avoided over a decade through modest improvements in service accessibility or outdoor environments. Recommended changes include adding primary care offices within walking distance, expanding public transit, and improving pedestrian safety.

The physician added that the risk factors identified are modifiable and not determined by genetics or age.