Loss of Slow-Wave Sleep Linked to Increased Risk of Dementia: JAMA

A new study published in Journal of American Medical Association from the Framingham Heart Study found Slow-wave sleep (SWS) loss linked to dementia risk. This relationship is especially relevant in light of age and genetic susceptibility to Alzheimer's disease. The 17-year study, which included 346 adults 60 years of age or older, found strong evidence that alterations in SWS may be a modifiable risk factor for dementia.

Long recognized for its involvement in removing toxic proteins connected to Alzheimer's disease, slow wave sleep (SWS) is a deep sleep phase that supports multiple brain functions. Still, it was unclear how directly it related to the onset of dementia. In order to resolve this uncertainty, this study looked at how age and genetic factors affect SWS.

The research, conducted from 2020 to 2023, found that as participants aged, they experienced a gradual decline in SWS. On average, SWS percentage decreased by 0.6% per year over the study's 17-year period. More strikingly, those who exhibited a more rapid loss of SWS were associated with an increased risk of dementia.

Each percentage decrease in SWS per year was linked to a 27% rise in the risk of dementia. These findings remained consistent even after adjusting for variables such as age, sex, genetic factors (APOE ε4 allele), and the use of medications.

The study also noted that the loss of SWS was more pronounced in individuals with a genetic predisposition to Alzheimer's disease, as indicated by the APOE ε4 allele. This suggests that genetic factors may interact with sleep patterns, potentially influencing the development of dementia.

Crucially, these findings open up the possibility that SWS loss could be a modifiable risk factor for dementia. If future research confirms these results, interventions aimed at promoting healthy sleep patterns could play a vital role in dementia prevention.

While current treatments for dementia remain limited, this study offers a glimmer of hope by identifying a potentially modifiable risk factor. By understanding the connection between SWS, aging, and genetics, researchers are taking significant steps toward unraveling the complex mysteries of dementia and developing new strategies for prevention and treatment. 

Reference:

Himali, J. J., Baril, A.-A., Cavuoto, M. G., Yiallourou, S., Wiedner, C. D., Himali, D., DeCarli, C., Redline, S., Beiser, A. S., Seshadri, S., & Pase, M. P. (2023). Association Between Slow-Wave Sleep Loss and Incident Dementia. In JAMA Neurology. American Medical Association (AMA). https://doi.org/10.1001/jamaneurol.2023.3889