A new study suggests that sleep habits may influence how certain genetic variants affect early brain and cognitive changes associated with Alzheimer’s disease.
Sleep may do more than help the brain recover from a busy day. New research suggests it could also influence how certain genes shape the earliest brain changes associated with Alzheimer’s disease.
Scientists at Edith Cowan University (ECU) found that sleep patterns may alter the effects of variants in a gene involved in the brain’s fluid and waste clearance systems. The findings could help explain why people with similar Alzheimer’s risk profiles do not always experience the same rate of cognitive or structural brain decline.
The study, led by ECU’s Centre for Precision Health (CPH), focused on aquaporin-4 (AQP4), a gene that helps regulate the movement of fluid through brain tissue.
AQP4 is closely connected to the brain’s waste removal processes, which become more active during sleep. These processes are thought to help clear metabolic waste, including proteins associated with Alzheimer’s disease, although researchers are still working to understand how strongly this system affects disease risk in humans.
“Our study shows that individuals carrying certain AQP4 variants showed faster gray matter loss when they reported shorter sleep,” researcher Dr Ayeisha Milligan Armstrong said.
“It’s not just which genes you carry; it’s how those genes interact with the world around you. The same variant can look protective or detrimental depending on how someone is sleeping. That’s important, because sleep is one of the few modifiable factors people can actually act on.”
Researchers examined 13 common AQP4 variants and compared them with participants’ self-reported sleep habits, brain scans, and cognitive performance.
The Same Sleep Problem May Not Affect Everyone Equally
Shorter sleep was associated with faster gray matter loss in some participants. In others, taking longer to fall asleep was linked to structural changes associated with lower brain volume.
The cognitive findings also varied by genetic profile. Among people reporting sleep disturbances, performance changed differently over time depending on which AQP4 variant they carried.
That variation is important because it suggests that poor sleep may not influence Alzheimer’s-related changes through a single, uniform pathway. A sleep pattern that appears especially harmful for one genetic group may have a weaker or different effect in another.
“We’ve known for a while that poor sleep and Alzheimer’s risk are linked,” researcher Dr Tenielle Porter said.
“What this shows is that rather than assuming everyone at risk follows the same pathway, a more targeted and personalized approach to Alzheimer’s prevention may be needed. But we’re not at the point of recommending genetic testing; our findings need replication in larger and more diverse cohorts.”
A Step Toward More Personalized Prevention
The results do not show that sleep problems directly cause Alzheimer’s disease, nor do they establish that changing sleep habits can reverse genetic risk. However, they raise the possibility that sleep interventions may eventually work better when tailored to a person’s biology.
The researchers recommended genetically informed clinical trials to test whether improving sleep can reduce risk or change long-term brain outcomes in people with specific AQP4 variants.
Such studies could also help determine whether sleep duration, sleep quality, or the time it takes to fall asleep matters most for different groups.
“This moves us closer to understanding why some people decline faster than others, even when they have similar risk on paper,” CPH Director Professor Simon Laws said.
“Identifying who is most vulnerable, and who is most likely to benefit from a particular lifestyle intervention, is where precision health needs to go rather than treating everyone at risk of Alzheimer’s the same way.”
Reference: “Evidence for direct and sleep-moderated relationships between aquaporin-4 genetic variants and Alzheimer’s disease phenotypes” by Tenielle Porter, Ayeisha Milligan Armstrong, Eleanor K. O’Brien, Vincent Doré, Pierrick Bourgeat, Mitchell Turner, Paul Maruff, Christopher C. Rowe, Belinda M. Brown, Victor L. Villemagne, Stephanie R. Rainey-Smith, Simon M. Laws and AIBL Research Group, 29 May 2026, Alzheimer’s & Dementia.
DOI: 10.1002/alz.71516
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