Sleep is the basic need of human beings, with the acceleration of the aging society, the sleep and health problems of middle-aged and elderly people have attracted more and more attention. The proportion of sleep disorders in middle-aged and elderly people is as high as 50%, and the change of sleep patterns, duration and sleep quality is also one of the important characteristics of the aging process. So for the middle-aged and elderly groups, what is the optimal sleep duration? How does sleep relate to their mental health and cognitive abilities? What are the genetic and neural mechanisms behind these relationships? These questions are of great significance for a better understanding of the aging process of people and the clinical guidance of healthy sleep for middle-aged and elderly people.
Professors Feng Jianfeng and Cheng Wei of the Institute of Brain-like Intelligence Science and Technology of Fudan University used big data analysis methods to study the genes, images, behaviors and other multi-dimensional data of nearly 500,000 people, and for the first time systematically characterized the nonlinear relationship between sleep duration and multi-dimensional phenotypes such as cognitive function and mental health in middle-aged and elderly people, and found the genetic and neural basis behind the relationship. On April 28, the study was published in Nature-Aging.
The proportion of sleep disorders in middle-aged and elderly people is as high as 50% of respondents
Based on the UK Biobank database (a prospective cohort study of about 500,000 people collecting genetic, physical and health data), the research team conducted non-linear modeling and analysis of sleep duration and cognitive, mental health and other wide behavioral representations of 38 to 73-year-old subjects, and found that sleep duration was significantly nonlinearly correlated with cognitive ability and mental health of middle-aged and elderly people, and there was a consistent 7-hour optimal sleep duration.
Further longitudinal follow-up data analysis showed that participants with relatively stable sleep duration showed better cognitive abilities and mental health.
“This suggests that 7 hours of sleep a day and regular sleep can promote the physical and mental health of middle-aged and elderly people.” Feng Jianfeng told China Science Daily.
Using the statistical modeling method of big data, the team further used neuroimaging multimodal data to study the neural mechanisms behind the above nonlinear relationships. The results showed that the sleep duration was also significantly nonlinearly correlated with the brain structure characteristics of the core brain region of the orbitofrontal cortex, hippocampus, temporal cortex, and central anterior gyrus and memory circuit (such as brain structure volume, cortical area, etc.), and was consistent with the behavioral findings with 7 hours as the turning point.
The overall research idea of the topic Courtesy of respondents
Further mediating analysis showed that these brain structures mediated the relationship between sleep duration and cognitive and mental health, suggesting that the function of these brain regions may be the neural basis for the nonlinear relationship between sleep duration and behavioral representations described above.
Finally, the research team further integrated the cross-scale data of genetics, imaging, sleep, cognition, and mental health, systematically characterized the interaction relationship between these five dimensions of data using structural equation models, and established a unified model of sleep problems from microscopic genetics to mesoscopic neuroimaging to macroscopic behavioral phenotypes.
“This provides us with a comprehensive perspective and a unified theory for understanding the complex relationship between sleep, cognition and mental health in the aging process.” Feng Jianfeng said.
Nonlinear association between sleep and brain volume Courtesy of respondents
This work is another new breakthrough in the field of sleep problems in the middle and elderly after the study of sleep in children and adults by Feng Jianfeng’s team. As early as 2018, the team found the basis of brain connection between adult sleep and depression comorbidities, and then found the comorbid relationship and key comorbid brain regions between children’s sleep disorders and ADHD in children’s sleep studies, and found the relationship between children’s sleep duration and multi-dimensional behavioral characterization and the neuroimaging mechanism behind them. A series of works have been published in the top journals of mental illness, journals of the American Medical Association – Psychiatry, Biological Psychiatry, and Molecular Psychiatry.
“In this study, we focus on the sleep problems of the elderly for the first time, systematically explain the relationship between sleep duration and the mental health of the elderly and their genetic and neural mechanisms, and improve an important part of the study of sleep problems in the whole life cycle population.” Feng Jianfeng said, “In the next step, we will also integrate multi-center, all-dimensional genetic imaging data around sleep, a major human health problem, systematically study the sleep problems of people in various life cycles, build a sleep spectrum of the whole life cycle, and provide scientific basis and practical guidance for sleep problems in people at all stages.” (Source: China Science Daily, Zhang Shuanghu, Huang Xin)
Related paper information:https://doi.org/10.1038/s43587-022-00210-2