In Starr County, Texas, near the state’s southern tip along the U.S.-Mexico border, escaping dementia can feel impossible. The condition affects about one in five adults on Medicare—more than double the national rate. “Everybody has somebody in their family” with dementia, Gladys Maestre, a neuroepidemiologist who studies aging at the University of Texas at Rio Grande Valley, told me.

For Jessica Cantú, it was her father, Tomas. He asked her, his eldest daughter, never to put him in a nursing home. She promised. “We take care of our own,” she told me. As Tomas’s dementia progressed, the former pastor held to his routines. He played with his 19 grandchildren. He preached Wednesday-night services and hand-delivered donations of rice, beans, and oil across the border. He fed his chickens and sheep, and ate his favorite homemade foods—pineapple upside-down cake, enchiladas with saltine crackers, and cream-of-mushroom chicken over rice.

Dementia looms over the Cantú family tree. Two of Tomas’s 10 siblings had it; Jessica wondered whether more might have, if they’d lived longer. Her maternal grandmother had dementia too. Seven months after her dad’s death, she began working as a nurse practitioner at the county’s first private Alzheimer’s-specific research site, El Faro Health and Therapeutics. “Patients will come in and say, ‘So have you figured it out? What is it?’” she told me. She tells them the truth. “I don’t know what it is that’s causing all of this.”

Dementia has no single trigger. As with many cancers, it can emerge from a lifetime of accumulated strain—from genetics, environment, and behavior. Researchers have identified a dozen risk factors that, if mitigated, could theoretically delay or prevent roughly 40 percent of cases worldwide: traumatic brain injury; conditions including high blood pressure, hearing loss, diabetes, and depression; habits such as smoking, inactivity, and heavy drinking; environmental and social forces including air pollution, social isolation, and limited education.

These “risk factors usually do not come (as) one; they come in clusters,” Maestre said—and in Starr County, an almost entirely Hispanic community, they quickly stack up. Nearly one in three people lives in poverty; a quarter lack health insurance. Chronic conditions are widespread—especially diabetes, high blood pressure, and heart disease—while access to care is limited: There’s just one primary-care physician for every 3,000 to 4,000 people, and few dementia specialists. Low education, language barriers, poor air quality, and extreme heat all compound the threat. These accumulate in cycles of grief and stress: The people I spoke with talked about deaths in the family followed by strokes that cascade into cognitive decline. Dementia isn’t simply a diagnosis. It’s a structural outcome.

Still, many in Starr County struggle to make sense of it. And no matter the cause—no matter which conglomeration of causes—they must live with dementia’s reality.

In the Rio Grande Valley, people are also outliving their odds. The area’s high dementia rate, Maestre has come to believe, may reflect not just risk but endurance: people living longer with the condition.

In general, research shows that Hispanic people tend to live longer than non-Hispanic white people, despite facing higher rates of chronic disease and steeper socioeconomic disadvantages—a pattern sometimes called the “Hispanic paradox.” And in the Rio Grande Valley, part of what might sustain people through dementia, Maestre suspects, is the culture: Dementia is seen less as a medical emergency and more as a natural, if difficult, phase of life. Elsewhere, people with dementia may live in nursing homes or take expensive new Alzheimer’s drugs with modest benefit. In Starr County, many older adults remain at home, surrounded by family who offer familiarity and stimulation. The care is physical, intimate—not clinical, but constant—and backed by research showing that familiar environments and home-based care can enhance both quality of life and cognitive function for people with dementia.

“He was never, never—since the day I brought him to my home—he was never one day alone,” says Juan “Manny” Saenz of his father, Francisco “Pancho,” who died at home last month at age 94. A professional body-shop painter, offshore fisherman, and lifelong jokester, Pancho began to grow forgetful and repetitive about a decade ago. Before Manny’s mom, Amaro, died, she made him promise not to put his father in a nursing home. Under Manny’s care, Pancho’s appearance was impeccable: He was bathed and perfumed, with trimmed nails and a neat mustache. He ate his meals on ceramic dishes, and relished his coffee-and-cookie merienda snack break—or breaks, on days he’d forget the previous ones. Manny, who lives in Rio Grande City, told me exactly what Jessica Cantú had: “We take care of our own.”

Monica Saenz Silva made a similar decision for her mother, Ramona—a bookkeeper at heart, the kind of person who kept every receipt for taxes and reminded her adult children to change their tires. She kept a running calendar of birthdays, not just for family and friends, but also for acquaintances, so she could wish them well. By 2019, a few years after her dementia symptoms appeared, “that was out the door,” Monica told me.

Today, Ramona will approach a taco or hamburger quizzically; she’s forgotten how to bite into them. At times, she doesn’t recognize the house where she’s lived for decades. Still, Monica is determined to keep her there. “You want to keep them home, so they’re in a familiar surrounding,” she said. “It’s not all the time that she doesn’t know she’s home.”

The response of many families here to dementia is shaped, partly, by limited treatment options: Alzheimer’s and related dementias have no cure, and available medicines can be expensive, be limited in their benefits, and come with potentially life-threatening side effects. In Starr County, some caregivers eschew pharmaceuticals for aromatic teas, herbal compresses, and prayers to soothe loved ones, Maestre said. Theirs is an ethic of endurance: If dementia is here, families ask, why not build a life, tenderly, around it?

Still, many don’t speak of it openly. Cantú told me that in her community, many still consider Alzheimer’s to be a normal part of aging—at most, a mental illness of old age, but almost never a neurodegenerative disease. “It’s okay to just be forgetful at the age of 70. It’s okay because Grandma and Grandpa were forgetful at the age of 70,” she said. “There’s no reason to discuss it.”

Still, some caregivers live with a sense of dread: In many cases, the disease does have a genetic component, and the structural forces that compounded their loved ones’ risk haven’t disappeared. They know their turn could be coming. Cantú frets about her mind; Monica Saenz Silva checks her memory every day. And they don’t necessarily want for themselves what they did for their parents: If his time comes, Manny Saenz wants to go to a nursing facility. “You won’t know anything, so it doesn’t matter,” he said. For him, the person with Alzheimer’s is spared the memory of their decline; the burden belongs to those who remember, and that’s a risk he doesn’t want to pass on.

Hispanic Americans face a significantly higher risk of dementia than white Americans, and are also one of the country’s fastest-aging groups. And yet, for decades, scientific understanding of dementia has drawn from data from mostly white, urban, and affluent populations; Hispanics make up fewer than 5 percent of participants in Alzheimer’s clinical trials. That limits researchers’ understanding of the condition. And the more they look, the less dementia seems like a single disease with a uniform pattern, and the more it appears to be a spectrum of diseases—each unfolding with its own course of symptoms, progression, and brain damage.

In some studies, researchers have detected amyloid plaques—the sticky protein clumps long considered hallmarks of Alzheimer’s—more frequently in the brains of white participants with dementia or mild cognitive impairment than in their Black, Asian, or Hispanic counterparts. In several studies that measured tau proteins, another key Alzheimer’s biomarker, Black adults with—or without—symptoms of dementia had lower levels than white participants. The genetic variant most strongly linked to Alzheimer’s disease is less common—and possibly less potent—among people with certain Hispanic backgrounds than among white people.

In 2021, the National Institute on Aging designated a new Alzheimer’s Disease Research Center in South Texas, co-directed by Maestre and Sudha Seshadri, a neurologist at the University of Texas at San Antonio. Their goal is to understand the Rio Grande Valley’s dementia cluster—and what can be done about it—in part by examining the effects of environmental hardship and linguistic isolation, and by investigating protective factors such as bilingualism and family networks.

Eventually, Maestre hopes that urban design (such as shaded walkways, gardens, and spaces for intergenerational interaction) could help reduce the region’s risks. “It’s not possible to put all the responsibility on the individual,” she told me. “You cannot do that on your own.”

And yet, resources remain scarce. Texas is home to about 460,000 people living with Alzheimer’s disease, but compared with other large states such as Florida and New York, it spends much less on dementia-related programs. (The Texas statehouse is considering a bill to establish a $3 billion fund for dementia research.)

For now, families like Jessica Cantú’s are left to do what they can. When her father was a pastor, he would tell her about the sick people he visited who would reach up with their arms (toward the kingdom of heaven, he said) before dying peacefully. In the final weeks of his life, he was still going to church and chatting with people at the H-E-B grocery store. But then Tomas lost his appetite and grew frail. One night, Jessica kept vigil at his bedside, afraid he’d fall trying to get up. In the quiet hours, she said, he lifted both arms toward the ceiling. “He was reaching up to the heavens, to the sky,” she said. “It just gave me that comfort to know that he was ready, and that everything was going to be okay.”

Masha Hamilton contributed reporting.

Support for this story was provided by the Magnum Foundation, in partnership with the Commonwealth Fund.