Significant Regional Variation in Dementia Incidence Found Among US Veterans
A large-scale cohort study examining over 1.2 million older US veterans has uncovered stark regional disparities in dementia incidence across the country, raising critical questions for clinicians and health policy makers about how local factors may be influencing cognitive health outcomes.
Conducted using data from the Veterans Health Administration (VHA), the study analyzed medical records of 1 268 599 veterans aged 65 years and older, spanning from 1999 to 2021, with an average follow-up period of 12.6 years. Veterans with prior dementia, missing ZIP codes, or no follow-up were excluded to ensure data integrity.
Researchers assessed dementia incidence by geographic region as defined by the Centers for Disease Control and Prevention (CDC), which divides the US into 10 regions. Diagnoses were based on International Classification of Diseases (ICD) codes and analyzed through Poisson regression models to adjust for age, sex, race/ethnicity, rurality, and cardiovascular comorbidities.
The most striking takeaway from the study is that dementia incidence varied significantly by region, even after adjusting for major risk factors. The Mid-Atlantic region had the lowest incidence rate at 11.2 cases per 1000 person-years, while the Southeast reported the highest rate at 14.0 cases per 1000 person-years. When compared to the Mid-Atlantic, the demographically adjusted risk of developing dementia was 25% higher in the Southeast, 23% higher in both the Northwest and Rocky Mountain regions, 18% higher in the South, and 12% higher in both the Midwest and South Atlantic regions.
These findings remained consistent even after further adjustments for rural residence, cardiovascular disease burden, and accounting for the competing risk of death.
At baseline, the average age was 73.9 years. Notably, 86.1% of participants were White, 7.2% Black, 0.8% Hispanic, 0.5% Asian, and 2% were women. This racial and gender distribution is reflective of the older VHA patient population and provides a context for interpreting the results within this unique demographic group.
The consistent and substantial regional disparities in dementia incidence suggest that beyond individual risk factors, systemic, environmental, or regional differences may be influencing outcomes.
“These findings highlight the importance of tailored health care strategies, public health initiatives, and policy reforms,” wrote the authors.
It also raises the possibility of region-specific risk profiles—potentially related to social determinants of health, access to care, diagnostic practices, or environmental exposures—that may demand more nuanced clinical approaches or localized prevention strategies.
Reference
Dintica CS, Bahorik AL, Xia F, Boscardin J, Yaffe K. Regional differences in dementia incidence among US veterans. JAMA Neurol. 2025;9:e251536. doi: 10.1001/jamaneurol.2025.1536
