Shi, Hui; Lipworth, Loren P.; Xiao, Qian; Han, Xijing; Mumma, Michael T.; Keohane, Laura M.; Yu, Danxia; Bolton, Corey J.; Archer, Derek B.; Hohman, Timothy J.; Full, Kelsie M. (2025). Five-year change in sleep duration and incident Alzheimer’s Disease and Related Dementias among lower-income older adults.Alzheimer’s and Dementia, 21(9), e70678. https://doi.org/10.1002/alz.70678
Little is known about how changes in sleep over time might affect the risk of developing Alzheimer’s disease and related dementias (ADRD). This study examined sleep patterns and dementia risk in adults enrolled in the Southern Community Cohort Study who were also part of Medicare. Participants reported their typical sleep duration at the start of the study and again at the first follow-up, which allowed researchers to calculate changes over roughly five years. Sleep was classified as short (<7 hours), recommended (7–9 hours), or long (>9 hours).
Among 17,945 participants, 2,093 developed ADRD during follow-up. Compared with people who consistently maintained recommended sleep (7–9 hours), those whose sleep patterns changed in less optimal ways had a 20–69% higher risk of developing dementia. For example, participants who went from long to recommended sleep had a 50% higher risk, long-to-long 56%, long-to-short 69%, short-to-long 49%, and short-to-short 20%.
These results suggest that changes in sleep duration over time—even when starting from short or long sleep—are linked to dementia risk. This study is especially important because it focuses on lower-income adults, a group that is often underrepresented in research on Alzheimer’s and related dementias. Maintaining consistent, recommended sleep duration may be an important factor in reducing dementia risk.
FIGURE 1
SCCS 5-year change in sleep duration and incident ADRD Flow Chart. ADRD, Alzheimer’s Disease and Related Dementias; FU1, the first follow-up visit in SCCS; SCCS, Southern Community Cohort Study.