Sleep duration polygenic score was associated with changes in the brain in cognitively healthy adults, with genetic predisposition for longer sleep duration associated with more favorable longitudinal trajectories against brain decline, a result mostly driven by younger adults.
Key Findings
Results
Higher Sleep PGI was associated with higher temporal white matter hyperintensity (WMH) volumes over time across the full age range.
This finding was observed in the total sample (n = 94) of cognitively healthy adults aged 20-80 years old.
The association held across the full age spectrum without requiring an age interaction term.
Temporal WMH volume was one of several brain measures examined, including total cortical thickness, gray matter volume, white matter volume, and WMH volume in multiple regions.
Results
Age was a significant moderator of the association between Sleep PGI and longitudinal changes in hippocampal volume, cortical white matter volume, and WMH volume (total and parietal).
Age moderation was identified through interaction terms between Sleep PGI, age, and time in study in the statistical models.
Analysis was performed in the total sample (n = 94) and stratified into three age-groups: young, middle, and old.
Generalized Estimating Equations (GEE) were used for statistical analysis.
The moderating effect of age indicates that the relationship between sleep genetics and brain changes differs across the lifespan.
Results
Genetic predisposition for longer sleep duration was associated with more favorable longitudinal brain trajectories, with this result primarily driven by younger adults.
More favorable trajectories were observed for outcomes related to brain decline over time.
The beneficial association was 'mostly driven by younger adults' as stated by the authors.
The study used longitudinal data from the Reference Ability Neural Network (RANN) and Cognitive Reserve (CR) studies.
Participants were cognitively healthy adults aged 20-80 years old.
Methods
The study used a Sleep Duration Polygenic Index (Sleep PGI) derived from recent genomic advances to capture genetic predisposition for sleep duration.
The Sleep PGI aggregates multiple genetic variants associated with sleep duration into a single score.
The index was applied to a sample of n = 94 cognitively healthy adults.
Brain measures examined included total cortical thickness, white matter volume, gray matter volume, and white matter hyperintensities (WMH) volume.
The study combined genomics and neuroimaging approaches to examine brain changes over time.
Background
Sleep is described as crucial for cognitive functioning, emotional regulation, and overall health, with genetics and sleep architecture having an intricate relationship with brain changes.
Recent advances in genomics and neuroimaging have illuminated the relationship between genetics, sleep architecture, and brain changes.
The study focused on cognitively healthy adults to examine normative brain aging in relation to sleep genetics.
The findings underscore 'the importance of maintaining optimal sleep duration and the potential for personalized interventions to improve sleep and brain health.'
What This Means
This research suggests that a person's genetic predisposition toward longer sleep duration — captured by a score called a Sleep Duration Polygenic Index (Sleep PGI) — is linked to how their brain changes over time. The study followed 94 healthy adults between ages 20 and 80, tracking brain measures like cortical thickness, gray and white matter volumes, and white matter hyperintensities (small bright spots on brain scans that can indicate wear on brain tissue). Researchers found that people with higher genetic scores for longer sleep tended to show more favorable brain trajectories over the study period, meaning their brains showed less decline.
One notable finding was that higher sleep genetics scores were associated with greater temporal white matter hyperintensity volumes over time in the full sample. However, when age was taken into account, it emerged as an important factor: the protective relationship between sleep genetics and brain health — particularly for hippocampal volume, white matter, and certain WMH measures — was most evident in younger adults rather than older ones. This suggests that the genetic influence on sleep may have its strongest brain-related effects earlier in life.
This research suggests that genetic factors influencing how long people sleep may shape brain health trajectories over decades of adult life. Because this is based on polygenic scores rather than measured sleep behavior, it points to an underlying biological link between sleep regulation and brain aging. The authors suggest these findings highlight the value of maintaining healthy sleep and the potential for personalized, genetically-informed approaches to protecting brain health — though larger studies will be needed to confirm and extend these findings.
Angeliki T, Silvia C, Seonjoo L, Christian H, Yian G, Yaakov S. (2026). Polygenic Index for Sleep Duration and Brain Changes over Time.. Medical sciences (Basel, Switzerland). https://doi.org/10.3390/medsci14010088