How much sleep you get may matter even more if you carry certain genetic variants linked to Alzheimer’s disease, according to new research that suggests genes and sleep habits work together to influence brain changes years before symptoms appear.

Researchers at Edith Cowan University examined the aquaporin-4 (AQP4) gene, which helps regulate fluid movement through the brain and plays a key role in the brain’s overnight waste-clearance system, often called the glymphatic system.

Scientists believe this system helps remove proteins such as amyloid-beta that accumulate in Alzheimer’s disease. Because the system is most active during sleep, researchers have increasingly focused on whether sleep quality influences long-term dementia risk.

Co-author Dr. Tenielle Porter said that, while poor sleep and Alzheimer’s risk have long been linked, the new results should not be viewed as evidence that genetic testing is ready for clinical use.

Dr. John Showalter, a physician specializing in dementia and cognitive impairment, agreed on the biological link between sleep and Alzheimer’s disease.

“We know that sleep and all-cause cognitive impairment, including Alzheimer’s disease, are linked,” Showalter told Newsweek. “Obstructive sleep apnea is associated with a 34 percent increase in all-cause dementia and insomnia has been reported to increase risk anywhere from 13 percent to 53 percent.”

Showalter added that excessive daytime sleepiness has also been associated with substantially higher amyloid accumulation over time, making the glymphatic system a particularly important area of Alzheimer’s research.

The new findings suggest some genetic risks may be amplified—or potentially mitigated—by sleep habits, raising the possibility that future prevention strategies could be tailored to an individual’s biology.

What the Study Found

Published in the June 2026 issue of Alzheimer’s & Dementia, the study analyzed 351 cognitively unimpaired adults in their mid-70s who already showed evidence of amyloid-beta accumulation and were enrolled in the Australian Imaging, Biomarkers and Lifestyle Study.

Researchers examined 13 common AQP4 variants alongside self-reported sleep measures, brain imaging and cognitive testing. Certain variants were associated with differences in brain volume, brain atrophy and cognitive performance, and those relationships often changed depending on sleep duration, sleep quality and how long participants took to fall asleep.

Participants carrying some AQP4 variants experienced faster gray matter loss when they reported shorter sleep durations. Others who took longer to fall asleep showed structural brain changes linked to reduced brain volume. Cognitive trajectories also differed depending on the combination of sleep disturbances and genetic profile.

The researchers concluded that sleep appears to act as a modifier of genetic risk, potentially influencing how Alzheimer’s-related changes develop over time.

Showalter said the findings resemble patterns already observed in cardiovascular disease, where genes and lifestyle factors interact rather than operating independently.

“It fits what we often see in medicine,” he said. “Genes may influence risk, but behavior and environment frequently determine how that risk is expressed.”

Researchers Urge Caution

Several of the researchers’ public comments originated from an Edith Cowan University press release issued in June 2026. Newsweek did not ask for additional comments from the study authors beyond those included in the university statement.

“Our study shows that individuals carrying certain AQP4 variants showed faster gray matter loss when they reported shorter sleep,” co-author Ayeisha Milligan Armstrong said in the university release. “It’s not just which genes you carry; it’s how those genes interact with the world around you.”

Importantly, the researchers cautioned against overinterpreting the findings.

“We’re not at the point of recommending genetic testing,” Porter said in the university’s June press release. “Our findings need replication in larger and more diverse cohorts.”

Porter said the research instead highlights how Alzheimer’s risk pathways may differ between individuals and suggests future prevention strategies could become more personalized.

That caution was echoed by Jessica McCarthy, a neuropsychologist specializing in dementia assessment and neurodegenerative disorders. She told Newsweek that the study’s immediate significance lies less in genetics and more in what it says about sleep.

“We cannot, and I mean absolutely cannot, ignore the fact that this study screams the importance of understanding and targeting modifiable risk factors such as sleep, aggressively and early,” she said.

McCarthy noted that sleep quality is influenced by factors throughout life, including mental health, hormonal changes, medical conditions and aging. She argued that public-health messaging should place greater emphasis on sleep hygiene long before people reach old age.

“We absolutely need to be moving, and quickly, in the direction of educating everyone about the importance of sleep hygiene and its longer-term impact on our health,” she said.

She also called for additional research into safer treatments for chronic sleep problems, noting concerns that some sleep medications have themselves been associated with increased dementia risk.

While McCarthy said genetic screening could eventually help personalize prevention strategies, she argued that the more actionable takeaway for readers is straightforward: improving sleep is something people can begin addressing now, regardless of their genetic profile.

The Bottom Line

The findings do not prove that improving sleep will prevent Alzheimer’s disease, nor do they establish that AQP4 genetic variants directly cause cognitive decline.

Instead, the study adds to growing evidence that sleep may be one of the most important—and potentially modifiable—factors influencing long-term brain health, while also suggesting that the effects of sleep may differ depending on an individual’s genetic makeup.

The study was first published online in Alzheimer’s & Dementia on May 29, 2026, appeared in the journal’s June 2026 issue, and was highlighted in an Edith Cowan University press release issued on June 22.

Contact Newsweek editors on this story: Kara Dolman and James Debens.

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