Sleep disturbance linked with higher risk of dementia, says study

Use of sleep medication and inability to fall asleep quickly are associated with an increased risk of developing dementia over a 10 year period, according to a study.

The research, published in the American Journal of Preventive Medicine, found a significant link between three measures of sleep disturbance and the risk for developing dementia, a neurodegenerative disease.

The researchers associate sleep-initiation insomnia (trouble falling asleep within 30 minutes) and sleep medication use with higher risk for developing dementia.

They 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, an Assistant Professor at SUNY Upstate Medical University, US.

The research 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 rapid eye movement (REM) sleep behaviour -- which is thought to play an important role in memory and learning -- less than five hours of sleep, and the use of short-acting benzodiazepines with cognitive decline.

The findings 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 US.

The 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," study co-investigator Margaret Anne Lovier from SUNY Upstate Medical University added.