A new study suggests that middle-aged adults who sleep six hours or less a night may be at a higher risk of developing dementia in later life.
According to the study published Tuesday in the scientific journal Nature Communications, people in their 50s or 60s who slept regularly for six hours or less each night were more likely than those who slept seven hours to be diagnosed with dementia than those who slept seven hours.
Even after controlling for heart, metabolic, and mental health problems, the study’s researchers found that 50-year-olds who slept six hours or less a night had a 22% higher risk of dementia later. Sixty-year-olds were 37% more likely to develop the disorder. Comparisons were made with people sleeping for seven hours each night.
A group of European researchers examined survey data from nearly 8,000 adults in the UK for more than 25 years and linked the data to dementia diagnoses in electronic medical records. The data came from a study by British officials at University College London that began in 1985. Since then, participants have been surveyed every four to five years.
Participants reported their sleep duration and some carried sleep trackers overnight to confirm that their self-information was accurate. Although the authors warned that the results cannot establish whether they are the least cause of dementia, they said the new study adds to short-term research showing that sleeping too little is related to the development of the disorder.
Other studies have shown that both lack of sleep and excess sleep are related to an increased risk, but this particular study showed no link between dementia and sleeping eight hours or more per night. Studies have also shown that interruptions that prevent people from sleeping well are associated with a higher risk of dementia later on.
Previous research also suggests that obesity, high systolic blood pressure, and mental health problems such as depression increase the risk of sleep problems and dementia.
“While we can’t say that sleep duration has a causal impact on dementia, it would be good to promote good sleep hygiene,” said Séverine Sabia, an epidemiologist at the French National Institute for Health and Medical Research. like Inserm, who is the lead author of the study. He said turning off mobile devices 30 minutes before bedtime and developing an exercise routine could help you fall asleep more easily.
What differentiates this study from others is that it analyzes the study subjects over a long period of time, said Rebecca Robbins, a sleep scientist at Boston’s Brigham and Women’s Hospital who did not participate in the study. Most published studies on sleep and dementia span 20 years or less, he said.
Adjustment for confounding issues such as depression was also an important feature of the study, he said. “This gives us more confidence that this study was looking exclusively at the relationship between dementia and sleep,” he said.
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He noted one limitation: researchers relied on self-reported data on sleep duration, which people tend to overestimate, Dr. Robbins said. But they were able to lessen it by confirming some of the self-reported data using sleep trackers, he said.
Given the conclusions, Dr. Robbins recommends people try to expose themselves to natural light during the day because this helps to synchronize their circadian rhythm with their surroundings. It is also recommended to have dinner at least an hour before bedtime, as digestion can make sleep difficult.
About half an hour to an hour before bedtime, he suggests doing reassuring things to get into the mind of going to bed.
“Do not expose yourself to bright blue light, take a hot shower or bath, light a candle, meditate. These little rituals can go a long way, ”he said.
Write to Sarah Toy at [email protected]
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