The total number of people living with Alzheimer’s is rising sharply, and it will continue to climb for decades. But the story is more nuanced than the headlines suggest. An individual’s risk of developing Alzheimer’s at any given age has actually been falling in the United States for the past 40 years. The increase in total cases is driven almost entirely by the fact that more people are living into their 80s and 90s, the ages when Alzheimer’s is most common.
The Numbers Are Growing Fast
About 6.9 million Americans age 65 and older are currently living with Alzheimer’s dementia. Without a major medical breakthrough, that number is projected to double to 13.8 million by 2060. Globally, 57 million people had dementia in 2021, and Alzheimer’s accounts for 60 to 70 percent of those cases. More than 60 percent of people with dementia live in low- and middle-income countries.
The U.S. population age 65 and older is expected to grow from 58 million in 2022 to 82 million by 2050. By 2030, every member of the baby boom generation will be at least 65. The 85-and-older group, where Alzheimer’s risk is highest, will more than double its share of the senior population, going from 11 percent in 2025 to 21 percent by 2050. Right now, about 2.5 million people with Alzheimer’s are 85 or older. By 2060, that number is expected to reach 6.7 million, nearly half of all Alzheimer’s cases.
Individual Risk Is Actually Declining
Here’s the part that surprises most people. When researchers at Duke University analyzed data from three large U.S. population studies spanning 1984 to 2021, they found that the percentage of people who had dementia at any given age dropped by roughly two-thirds over 40 years. Each successive generation has had a lower risk than the one before it, with age-adjusted dementia prevalence declining about 2.5 to 3.7 percent per year across different study periods.
This matters because the alarming projections of cases doubling by 2050 assume that the rate of dementia at each age stays the same, and it hasn’t. When the Duke team applied the actual declining rates to population projections, they estimated only a 25 percent increase in total cases by 2050, not the doubling that’s commonly cited. The rise in total cases is real, but it’s being powered by demographics, not by an escalating disease.
The likely explanation for the declining per-person risk: improvements in education, cardiovascular care, and overall health across generations. People reaching age 75 today grew up with better nutrition, more years of schooling, and more effective treatment for conditions like high blood pressure and high cholesterol than those who reached 75 in the 1980s.
Metabolic Health Is Pushing in the Other Direction
While some factors have improved, others are working against us. Diabetes, obesity, and high blood pressure all accelerate the brain changes associated with Alzheimer’s, and all three conditions are surging worldwide. People with type 2 diabetes face roughly double the risk of developing dementia compared to those without it. Obesity raises the risk by about 31 percent. Projections suggest that by 2030, up to 20 percent of the global population will be obese.
These conditions don’t just coexist with Alzheimer’s. They actively contribute to it. When the body becomes resistant to insulin, the same enzymes that would normally help clear harmful protein buildup in the brain get diverted to processing excess insulin instead. Obesity and diabetes also trigger chronic, low-grade inflammation throughout the body that eventually reaches the brain. High blood pressure damages the small blood vessels that keep brain tissue healthy. The combined effect means that the global rise in metabolic disease could offset some of the gains from better education and cardiovascular care, particularly in younger generations that have higher rates of obesity than their parents did.
The Burden Is Not Evenly Distributed
In the United States, Black Americans are about twice as likely as white Americans to develop Alzheimer’s, and Hispanic Americans are roughly 1.5 times as likely. These gaps are striking, but they largely reflect inequalities in health care access, education, income, and the chronic conditions that raise Alzheimer’s risk. One study that adjusted for demographics, genetics, other health conditions, lifestyle, and socioeconomic status found the difference between Black and white participants shrank to just 9 percent and was no longer statistically significant.
Globally, the disparities are even starker. Some regions in Latin America, including Mexico, Brazil, Central America, and the Andean countries, are projected to see dementia prevalence increase by more than 400 percent between 2010 and 2050. These countries face a collision of rapid population aging, rising rates of diabetes and obesity, and limited access to the health care resources that have helped bring per-person risk down in wealthier nations.
Prevention Could Change the Trajectory
A 2024 report from the Lancet Commission on dementia identified 14 modifiable risk factors that, together, account for a substantial share of dementia cases worldwide. The list includes less education, hearing loss, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution, social isolation, untreated vision loss, and high LDL cholesterol. The last two were added based on newly compelling evidence.
None of these guarantees Alzheimer’s, and addressing them doesn’t eliminate the risk entirely. But the fact that age-adjusted rates have been falling for decades in the U.S. suggests that population-level improvements in these areas genuinely move the needle. Better management of blood pressure and cholesterol, more years of education, hearing aids, staying physically active, and maintaining social connections all appear to build resilience against cognitive decline. The countries and communities that invest in these areas are likely to see smaller increases in Alzheimer’s cases, even as their populations age.
Better Diagnosis Is Changing What Gets Counted
Part of the apparent rise in Alzheimer’s reflects better detection. In 2024, the National Institute on Aging and the Alzheimer’s Association updated their diagnostic guidelines to include blood-based biomarkers for the first time. Previously, confirming Alzheimer’s required either a spinal tap or an expensive brain scan. Blood tests are cheaper, easier, and far less invasive, which means more people can be screened and diagnosed earlier. As these tests become standard in clinical practice, the recorded number of Alzheimer’s cases will rise simply because cases that previously went undetected are now being identified. This is an increase in diagnosis, not necessarily an increase in disease.