Sleep is inextricably related to good health. New research from Brigham and Women’s Hospital examines the connection between sleep disruptions and deficiencies and the risk of dementia in older adults and death, finding that those who reported getting less than five hours of sleep per night had twice the risk of dementia as those who reported getting 7-8 hours of sleep per night. The researchers also discovered connections between sleep disruption and sleep deprivation and overall mortality risk. The findings were published in the journal Aging. “Our findings show a correlation between sleep deprivation and dementia risk, reiterating the importance of helping older people get enough sleep each night,” said lead author Rebecca Robbins, Ph.D., of the Division of Sleep and Circadian Disorders. Robbins and colleagues used nationally representative data from older adults participating in the National Health and Aging Trends Study to examine the correlation between sleep quality and quantity and the risk of dementia and death (NHATS).

In 2013 and 2014, a total of 2,610 people completed sleep questionnaires. The researchers looked at participants’ responses to questions about alertness, nap frequency, how long it took them to fall asleep, sleep quality (good/very good, fair, very poor/poor), sleep length, and snoring, as well as other aspects of sleep disruption and deficiency. They also collected data on patient outcomes such as dementia and death from any cause for up to 5 years after the survey (as required from health care proxies).

Overall, they discovered a clear connection between a variety of sleep disruption and deficiency variables and the occurrence of dementia over time. Taking 30 minutes or more to fall asleep on a daily basis was related to a 45 percent increased risk of incident dementia. Having trouble remaining alert on a regular basis, napping regularly, reporting poor sleep quality, and sleeping five or fewer hours per night were all related to an increased risk of death.

“Our study demonstrates that very short sleep durations and poor-quality sleep in the elderly increase the risk of developing dementia and earlier death. There should be an increased focus on obtaining healthy sleep in older adults,” said second author Stuart Quan, MD, of the Division of Sleep and Circadian Disorders.