People Sleep Less in Middle Age
However, it is worth noting that long-term lack of sleep will not only lead to neurasthenia, memory and immunity decline, but also increase the risk of heart disease and cancer. At the same time, sleep disorders are an important feature of Alzheimer’s. Researchers from the University of Paris in France have published a study in the journal Nature Communications entitled: Association of sleep duration in middle and old age with incidence of dementia.
The study analyzed the 25-year follow-up data of 7959 participants and reported that middle-aged and elderly people with long-term sleep less than 6 hours were associated with a 30% increased risk of dementia. Although this finding cannot establish an absolute causal link, it at least shows that there is an important link between sleep duration and the risk of dementia.
In modern society, with the increase of human life expectancy and the change of living habits, the prevalence of Alzheimer's disease is also rising. It is difficult for people with dementia to take care of themselves, which has caused a great burden on the family and society. Even more regrettable, there is currently no effective treatment for Alzheimer's disease.
Research data shows that about 10 million new cases of dementia are reported every year worldwide, and one of the common symptoms is sleep changes. Not only that, more and more evidence suggests that shorter sleep time in the elderly (65 years and older) is associated with an increased risk of dementia, but it is unclear whether this association is also true in younger people.
In this study, Séverine Sabia and his research team analyzed data from the Whitehall II study (also known as the "Stress and Health" study) at University College London (UCL) in the United Kingdom. The study investigated the health status of 7,959 British adults since 1985, which was followed up for 25 years. These participants self-reported their sleep duration, and some would wear wearable devices to sleep to confirm whether the reported sleep duration was accurate.
Through the Whitehall II study cohort, the research team verified the relationship between sleep time of middle-aged and elderly people (50, 60, and 70 years old) and dementia events, and investigated whether the change pattern of sleep time during this period is related to dementia. In addition, the researchers also investigated whether middle-aged mental disorders affect the relationship between sleep time and dementia.
The results of the study show that people who sleep less than 6 hours a night at the age of 50 or 60 have a higher risk of developing dementia compared to the normal sleep time (7 hours). People who have been in a shorter sleep pattern from middle age to old age (between 50-70 years old) have a 30% increased risk of dementia. And, this has nothing to do with known risk factors for dementia such as sociodemography, behavior, cardiometabolic and mental health status. This confirms that short sleep time in middle-aged people is associated with an increased risk of late-onset dementia.
All in all, this longitudinal study through statistical analysis of the long-term follow-up data of nearly 8,000 participants shows that insufficient sleep time during the middle-aged and old age will increase the risk of dementia. From this it seems that sleep time is closely related to cognitive ability, which reminds us to do our own time management, no matter how stressful work and life are, we must try our best to ensure our own sleep time!