Improving Deep Sleep May Prevent Dementia
Published:05 Dec.2023 Source:Monash University
As little as 1 per cent reduction in deep sleep per year for people over 60 years of age translates into a 27 per cent increased risk of dementia, according to a study which suggests that enhancing or maintaining deep sleep, also known as slow wave sleep, in older years could stave off dementia. The study looked at 346 participants, over 60 years of age, enrolled in the Framingham Heart Study who completed two overnight sleep studies in the time periods 1995 to 1998 and 2001 to 2003, with an average of five years between the two studies.
These participants were then carefully followed for dementia from the time of the second sleep study through to 2018. The researchers found, on average, that the amount of deep sleep declined between the two studies, indicating slow wave sleep loss with ageing. Over the next 17 years of follow-up, there were 52 cases of dementia. Even adjusting for age, sex, cohort, genetic factors, smoking status, sleeping medication use, antidepressant use, and anxiolytic use, each percentage decrease in deep sleep each year was associated with a 27 per cent increase in the risk of dementia.
Researchers also examined whether genetic risk for Alzheimer's Disease or brain volumes suggestive of early neurodegeneration were associated with a reduction in slow-wave sleep. They found that a genetic risk factor for Alzheimer's disease, but not brain volume, was associated with accelerated declines in slow wave sleep.