New Breakthroughs in Alzheimer’s Causes, Care

There are over 7 million people living with Alzheimer’s disease in the U.S., and that number is projected to nearly double in the next 25 years.

But our knowledge about the causes of and care for Alzheimer’s is also expanding, offering hope to people who currently, or may one day, live with the disease.

The changes in the brain that lead to Alzheimer’s disease tend to happen as people get older, and Alzheimer’s risk increases with age. Some previous studies have also found links between cognitive decline and health conditions like heart disease, high blood pressure, and depression.

Now, researchers at Rollins are discovering new evidence to link lifestyle and environmental factors to Alzheimer’s risk.

Air Pollution and Alzheimer’s Disease

An 18-year study of over 27 million Americans 65 and older found that air pollution with fine particulate matter (PM2.5) might be the direct cause of many cases of Alzheimer’s

“The reason this is particularly important is that PM2.5 is known to be associated with high blood pressure, stroke and depression—all of which are associated with [Alzheimer’s disease],” Kyle Steenland, PhD, the study’s senior author, told ABC News. “So, from a prevention standpoint, simply treating these diseases will not get rid of the problem. We have to address exposure to PM2.5.” 

PM2.5 pollution comes from fuel combustion—driving vehicles, burning wood in a fireplace or stove, or large-scale power generation.

The Role of Social Connection

A study from late 2025 found that social isolation could lead to faster cognitive decline, including developing Alzheimer’s disease.

Social isolation is a lack of social connections, which can come from living alone and not having frequent contact or close relationships with others. About 25% of older adults worldwide are socially isolated.

“Engaging with others, whether they are close to us or strangers, is stimulating and gives opportunities to practice our cognitive skills,” says Solveig Cunningham, PhD, senior author of the study.

The study found that building community to reduce social isolation can help prevent cognitive decline, regardless of gender, race, ethnicity, or level of education.

Caring for People Living with Alzheimer’s

One way that many older adults have social connection and interaction is through caregivers. Caregiving for older adults frequently falls on friends and family members, who are often unpaid.

A recent report from the National Alliance for Caregiving found that 25% of adults in the U.S. are caregivers, and 27% of caregivers care for someone with Alzheimer’s, dementia, or another memory impairment. These caregivers are prone to burnout and poor mental health.

“Many care partners are cutting back on work. They’re leaving the workforce. And that results in impacts to their earnings,” says Regina Shih, PhD, professor of epidemiology, in a recent interview with Scientific American. “Family caregivers, especially to people with dementia, experience much higher rates of mental health, as well as physical, impacts.”

The interview—which also included other Alzheimer’s, dementia, and caregiving experts—focused on a potential path to easing caregiver burden: artificial intelligence.

Smart home technology like sensors to detect and prevent falls and chatbots to help navigate care decisions can help support caregivers and the people living with Alzheimer’s disease who they care for. But researchers also stress that it is important to remember that nothing can replace human interaction and empathy.