These U.S. Regions Have Higher Dementia Rates — Are You at Risk?

SAN FRANCISCO — If you’re planning retirement and worried about dementia, your zip code might matter more than you think. A new study tracking over 1.2 million American veterans across two decades reveals that dementia rates vary dramatically across U.S. regions in ways that can’t be explained by age, education, or health conditions.

According to the study published in JAMA Neurology, veterans in the Southeast develop dementia at rates significantly higher than those in the Mid-Atlantic, and the gap persists even when researchers account for traditional risk factors. In the Southeast—covering Kentucky, Tennessee, Alabama, and Mississippi—dementia strikes 14 out of every 1,000 people annually. Compare that to the Mid-Atlantic region, where just 11.2 cases occur per 1,000 people each year.

When applied to large populations, these differences translate into thousands of additional families grappling with dementia’s devastating effects.

Scientists from the University of California, San Francisco, analyzed Veterans Health Administration data spanning October 1999 to September 2021, following participants for an average of 12.6 years. The study examined 1,268,599 veterans aged 65 and older from all 50 states, representing roughly 20% of the total VHA population during the study period.

While the veteran population skews heavily male (98%), it includes people from diverse racial, ethnic, and socioeconomic backgrounds. Researchers used the CDC’s regional classification system, which divides the United States into 10 distinct areas.

After the Southeast’s 25% higher rate, the Northwest (Alaska, Idaho, Oregon, and Washington) and the Rocky Mountains (Colorado, Montana, North Dakota, South Dakota, Utah, and Wyoming) both showed 23% higher rates compared to the Mid-Atlantic region.

The South, encompassing Arkansas, Louisiana, New Mexico, Oklahoma, and Texas, registered 18% higher rates. The Midwest showed 12% higher rates, while the South Atlantic region had rates 12% above the Mid-Atlantic baseline. Even the Great Lakes region, despite including major urban centers like Chicago, showed increases of 7% above the Mid-Atlantic rate.

Why Traditional Risk Factors Don’t Explain the Pattern

Researchers anticipated that demographic and health factors would explain most of the regional variation. They systematically adjusted for age, sex, race and ethnicity, education levels, rural versus urban residence, and cardiovascular conditions including diabetes, hypertension, and heart disease.

Even after taking all of these into account, the regional differences barely changed. This persistence points to location-specific factors—whether environmental, cultural, lifestyle-related, or tied to healthcare practices—that play a significant role in dementia development.

Some clues did emerge from the data. Regions with higher dementia rates often had populations with lower educational attainment and higher rates of cardiovascular disease. The Southeast, for instance, had the highest prevalence of diabetes and hypertension among study participants. However, these factors alone couldn’t explain the persistent regional patterns.

Environmental and Lifestyle Factors

Living in rural areas has long been associated with higher dementia risk. While some high-dementia regions like the Rocky Mountains and parts of the Midwest do have larger rural populations, the pattern isn’t consistent across all areas. Rural areas face unique challenges that could contribute to cognitive decline: limited access to specialists can delay diagnosis and treatment, higher rates of social isolation reduce cognitive engagement, and environmental exposures may vary between communities.

Air quality differs across the United States, with some areas experiencing higher levels of pollution linked to cognitive decline. Diet patterns also vary regionally, from Mediterranean-influenced eating habits common in some coastal areas to higher processed food consumption typical in other regions.

Environmental toxin exposure could be another cause for higher dementia rates. Different regions have distinct histories of industrial activity, agricultural practices, and environmental contamination that could have long-term effects on cognitive health.

What This Means for American Healthcare

Regions with consistently higher dementia rates may need additional resources for diagnosis, treatment, and support services. Understanding these patterns could help target prevention efforts and improve outcomes for millions of Americans.

Future research will likely focus on identifying the specific factors driving these regional differences. Researchers are calling for studies that incorporate more detailed environmental exposures and measures of social connectedness to better understand the complex web of factors influencing dementia risk.

Over 6 million Americans are currently living with dementia, and that number is expected to nearly triple by 2050. Identifying and addressing regional risk factors could help reduce this condition’s devastating impact on families and communities nationwide. While researchers work to understand why geography matters so much for brain health, families in high-risk regions can focus on proven strategies like staying physically active, maintaining social connections, and managing cardiovascular health.