Alzheimer’s disease (AD) is a progressive neurological disorder that gradually destroys memory and thinking skills, making it the most common cause of dementia. The burden of this disease varies significantly across the United States. Understanding these geographical differences, measured using age-adjusted rates, is central to effective public health planning and resource allocation. This analysis identifies the state with the highest prevalence rate and explores the factors creating this national disparity.
Identifying the State with the Highest Rate
The state estimated to have the highest age-adjusted prevalence rate of Alzheimer’s disease among adults aged 65 and older is Maryland. Based on 2020 population estimates, Maryland had an estimated Alzheimer’s prevalence rate of 12.9% within its senior population. This rate places it narrowly ahead of other states facing a high burden, such as New York (12.7%) and Mississippi (12.5%).
It is important to distinguish between the highest rate and the highest number of people affected. States with the largest populations, such as California and Florida, inevitably have the highest total number of residents living with Alzheimer’s, with California having an estimated 719,000 cases. The prevalence rate, however, accounts for the size of the senior population, providing a more accurate measure of the disease burden relative to the overall number of older residents. The high rate in Maryland reflects a significant proportion of its older citizens living with the condition.
Understanding How Rates Are Calculated
The figures used to compare states are based on an age-adjusted prevalence rate, which is a standardized measurement. This calculation is necessary because age is the largest risk factor for Alzheimer’s disease. If a state had a higher number of older residents, its raw case count would be disproportionately large, making a direct comparison to a state with a younger population unfair.
Age adjustment mathematically corrects for population differences by applying the disease rates found in specific age groups within a state to a standard reference population. This process allows health officials to accurately compare the underlying risk of Alzheimer’s across states, independent of their unique age distributions. Primary data sources include the Centers for Disease Control and Prevention and the Alzheimer’s Association, which use demographic data combined with cognitive study results.
Key Factors Driving State-to-State Variation
The variation in Alzheimer’s prevalence rates is driven by demographic composition and underlying health disparities across regions. The most significant factor is the concentration of the oldest age groups, particularly individuals aged 85 and older. Because the risk of developing Alzheimer’s doubles roughly every five years after age 65, states with a higher proportion of the very old will see higher prevalence rates.
Substantial disparities exist along racial and ethnic lines, which heavily influence regional rates. Older Black Americans are estimated to be about twice as likely to have Alzheimer’s or other dementias compared to older White Americans. Older Hispanic Americans are about one and a half times as likely to have the disease. States in the East and Southeast, including Maryland and Mississippi, have high prevalence rates partly due to a larger proportion of Black and Hispanic residents in their senior populations.
The geographical clustering of poor health and lifestyle factors contributes to the variation. Co-morbidities that increase the risk of cognitive decline, such as high rates of obesity, diabetes, and cardiovascular disease, are more prevalent in certain regions, particularly the Deep South. These vascular and metabolic conditions are linked to the development of Alzheimer’s disease. Addressing these underlying health issues represents an opportunity for public health efforts to reduce dementia risk.
National Scope and Comparative Data
The overall picture of Alzheimer’s in the United States shows that approximately one in nine people aged 65 and older, or about 11% of the senior population, is living with the disease. This national average provides a benchmark for understanding state-level variations. The estimated number of Americans aged 65 and older living with Alzheimer’s is projected to be around 7.2 million in 2025.
While the East and Southeast show the highest rates, states with the lowest prevalence rates are generally found in the Western and Mountain regions. These low-ranking states often share common characteristics, such as younger overall populations or different socioeconomic and racial demographics. States with a lower proportion of older adults and a higher median age for the general population tend to report lower rates of the disease. The regional differences underscore that the challenge of Alzheimer’s is not uniform across the nation, requiring tailored public health responses.