Summary: A new study reveals people who have trouble falling asleep within 30 minutes and those who use sleep medications are at increased risk of developing dementia as they age. However, those who have difficulty falling back asleep after they woke up during the night are less likely to develop dementia.
Adding to the growing body of evidence on sleep disturbances and cognitive impairment, new research finds significant links between three measures of sleep disturbance and the risk for developing dementia over a 10-year period.
The results, reported in the American Journal of Preventive Medicine, published by Elsevier, associate sleep-initiation insomnia (trouble falling asleep within 30 minutes) and sleep medication use with higher risk for developing dementia.
The investigators also found that people who reported having sleep-maintenance insomnia (trouble falling back to sleep after waking) were less likely to develop dementia over the course of the study.
“We expected sleep-initiation insomnia and sleep medication usage to increase dementia risk, but we were surprised to find sleep-maintenance insomnia decreased dementia risk,” explained lead investigator Roger Wong, PhD, MPH, MSW, an Assistant Professor in the Department of Public Health and Preventive Medicine, SUNY Upstate Medical University, Syracuse, NY, USA.
“The motivation behind this research was prompted on a personal level. My father has been experiencing chronic sleep disturbances since the COVID-19 pandemic began, and I was concerned how this would affect his cognition in the future. After reading the existing literature, I was surprised to see mixed findings on the sleep-dementia relationship, so I decided to investigate this topic.”
This research is novel because it is the first to examine how long-term sleep disturbance measures are associated with dementia risk using a nationally representative US older adult sample. Previous research has associated REM sleep behavior, sleep deprivation (less than five hours of sleep), and the use of short-acting benzodiazepines with cognitive decline. Their results for sleep-maintenance insomnia support other recent studies using smaller, separate data samples.
This study used 10 annual waves (2011−2020) of prospective data from the National Health and Aging Trends Study (NHATS), a longitudinal panel study that surveys a nationally representative sample of Medicare beneficiaries aged 65 years and older within the USA. This study included only people who were dementia-free at baseline in 2011.
There is no cure for dementia and recent pharmaceutical approaches to treat dementia have had limited success, pointing to the importance of preventive approaches to dementia.
“By focusing on the variations in sleep disturbances, our findings can help to inform lifestyle changes that can reduce dementia risk,” explained co-investigator Margaret Anne Lovier, MPH, Department of Public Health and Preventive Medicine, SUNY Upstate Medical University, Syracuse, NY, USA.
While the mechanism for decreased dementia risk among those with sleep-maintenance insomnia is still unknown, the investigators theorize that greater engagement in activities that preserve or increase cognitive reserve may thereby decrease dementia risk.
Recent evidence indicates there is a higher prevalence of sleep disturbances among older adults than among other age groups. This could be attributed to a variety of factors including anxiety about the COVID-19 pandemic or warmer nights as a consequence of climate change.
“Older adults are losing sleep over a wide variety of concerns. More research is needed to better understand its causes and manifestations and limit the long-term consequences,” added Dr. Wong.
“Our findings highlight the importance of considering sleep disturbance history when assessing the dementia risk profile for older adults. Future research is needed to examine other sleep disturbance measures using a national longitudinal sample, whether these sleep-dementia findings hold true for specific dementia subtypes, and how certain sociodemographic characteristics may interact with sleep disturbances to influence dementia risk.”
About this dementia and sleep research news
Author: Eileen Leahy Source: Elsevier Contact: Eileen Leahy – Elsevier Image: The image is in the public domain
Sleep Disturbances and Dementia Risk in Older Adults: Findings from 10 Years of National U.S. Prospective Data
Previous research has identified a link between sleep disturbances and cognitive impairment; however, no study has examined this relationship using a national United States sample. This study examines how multiple longitudinal measures of sleep disturbances (sleep-initiation insomnia, sleep-maintenance insomnia, sleep-medication usage) are associated with dementia risk.
Ten annual waves (2011–2020) of prospective cohort data from a nationally representative U.S. sample of adults aged ≥65 years were analyzed from the National Health and Aging Trends Study. Sleep disturbances were converted into a longitudinal score and measured as sleep-initiation insomnia (trouble falling asleep in 30 minutes), sleep-maintenance insomnia (trouble falling asleep after waking up early), and sleep-medication usage (taking medication to help sleep). Cox regression models analyzed time to dementia diagnosis for a sample of 6,284 respondents.
In the unadjusted model, sleep-initiation insomnia was significantly associated with a 51% increased dementia risk (hazard ratio=1.51, 95% CI=1.19, 1.90). Adjusted for sociodemographics, sleep-medication usage was significantly associated with a 30% increased dementia risk (adjusted hazard ratio=1.30, 95% CI=1.08–1.56). Adjusted for sociodemographics and health, sleep-maintenance insomnia was significantly associated with a 40% decreased dementia risk (adjusted hazard ratio=0.60, 95% CI=0.46, 0.77).
These findings suggest that sleep-initiation insomnia and sleep-medication usage may elevate dementia risk. On the basis of the current evidence, sleep disturbances should be considered when assessing the risk profile for dementia. Future research is needed to examine other sleep disturbance measures and to explore the mechanisms for decreased dementia risk among older adults with sleep-maintenance insomnia.