Regional Differences in Dementia Incidence Among US Veterans

Area of Science:

• Gerontology
• Epidemiology
• Public Health

Background:

• Previous dementia incidence studies in the US lacked regional specificity, obscuring geographic variations and potential contributing factors.
• Understanding regional differences in dementia incidence is crucial for effective public health interventions and healthcare resource allocation.

Purpose of the Study:

• To investigate geographic disparities in dementia incidence among older adults within the US Veterans Health Administration (VHA) system.
• To identify specific US regions with higher or lower dementia incidence rates.

Main Methods:

• A cohort study analyzed data from 1,268,599 dementia-free veterans aged 65+ from October 1999 to September 2021.
• Dementia incidence was calculated per 1,000 person-years for zip codes within 10 US regions defined by the CDC.
• Poisson regression models assessed regional differences in incidence rate ratios, adjusting for covariates like age, sex, rurality, and cardiovascular comorbidities.

Main Results:

• Dementia incidence rates per 1,000 person-years were lowest in the Mid-Atlantic (11.2) and highest in the Southeast (14.0).
• Compared to the Mid-Atlantic, the Southeast (RR, 1.25), Northwest (RR, 1.23), and Rocky Mountains (RR, 1.23) showed the highest demographically adjusted incidence rates.
• These regional variations persisted after adjusting for rurality, cardiovascular comorbidities, and the competing risk of death.

Conclusions:

• Significant geographic variation in dementia incidence exists among older US veterans, independent of key demographic and health factors.
• These findings underscore the necessity for tailored healthcare planning, targeted public health initiatives, and informed policy development to address regional dementia disparities.