The importance of sleep is continually being assessed and better understood. Any parent who has had sleep training for their baby can attest to this. Any doctor who has spent countless nights on call, functioning with minimal or no sleep, can attest to this. Any student who has spent a sleepless night and then regretted it the next day can attest to this. But for older people, the impact of sleep deprivation can lead to a higher risk of dementia and an even higher risk of all-cause mortality. Nearly 6 million adults live with Alzheimer’s disease or other forms of dementia in the United States alone, and it is estimated that by 2050, 16 million adults in the United States will be living with Alzheimer’s disease. ‘Alzheimer’s. Researchers based at Brigham and Women’s Hospital and Boston College published their findings on how poor sleep may be linked to dementia and death in this month’s journal Aging.
The group analyzed data from the National Health and Aging Trends Study (NHATS), which includes Medicare-eligible people aged 65 and older in the United States. This longitudinal survey included questions about sleep duration (number of hours per night), sleep latency (how long, on average, it takes to fall asleep each night) as well as whether or not to sleep. take a nap during the day. Questions also included the presence or absence of difficulty concentrating during the day, dementia, and all-cause mortality over a five-year study period.
Study investigators extracted data from 2,810 adults (mean age 76) from the study population to assess the relationship between sleep disturbances, dementia, and all-cause mortality. They found that compared to those who reported sleeping 7 to 8 hours a night, those who slept 5 hours a night or less had a double the risk of developing dementia. Those who took more than 30 minutes to fall asleep each night had a 45% higher risk of developing dementia. Those who reported poor sleep, as well as the need for daily naps or difficulty staying alert during the day, also experienced an increase in all-cause mortality over the five-year period.
Conversely, previous studies have shown that better quality and duration of sleep is linked to a lower incidence of dementia and death. A 2018 study published in the Journal of the American Geriatric Society followed 1,517 Japanese adults aged 60 and over over a 10-year period. They found that adults who slept between 5 and 6.9 hours per night had a lower incidence of dementia and death during the study period.
Sleep is often underestimated as an essential part of maintaining good health. Sleep disorders include insomnia (difficulty or inability to fall asleep), seen in up to a third of adults, sleep apnea or snoring, restless legs syndrome, narcolepsy and nearly 100 other diagnoses related to sleep. Those with neurological disorders have a higher incidence of sleep problems, so, as was the case in the two studies above, it is always difficult to distinguish between causation and correlation. Additionally, people with sleep disorders such as obstructive sleep apnea are more likely to develop cardiovascular problems, obesity, and type 2 diabetes, and it’s just as difficult to assess causation.
The last eleven months of the Covid-19 pandemic have resulted in a higher incidence of housing insecurity and homelessness. As I wrote about in a recent Forbes room, these problems are also associated with poor sleep. Data from several studies all point to an association between better sleep and better health. As the cause and effect between sleep and brain health and longevity remain difficult to demonstrate, further study and special attention paid to sleep hygiene and the assessment and treatment of sleep disorders to l Adulthood should be a problem addressed in the aging population, before old age.