The physiological processes in humans rely heavily on sleep to maintain normal operation. A recent PLOS Medicine journal study determined the relationship between sleep time and incidence of multiple diseases in the elderly (i.e., 50-70 years old). It is worth noting that the study used twenty-five years of follow-up data for analysis.
lack of evidence related to sleep duration and health status
Although several studies have shown the relationship between sleep duration and the manifestation and mortality of chronic diseases such as cancer and cardiovascular disease, the nature of this association is not clear.
When more than one chronic disease is common in the same body, it is called a multiple disease. However, there are not many studies on the relationship between multiple diseases and sleep duration. Furthermore, whether sleep duration affects health, manifestation of chronic disease and subsequent mortality is unclear.
Currently, it is recommended that the elderly sleep 7 to 8 hours; however, short or long sleep time will increase the risk of disease, which should be discussed in future research. Potential biological mechanisms associated with short-term sleep and comorbidities are available. However, the effect of prolonged sleep on chronic disease manifestations is not yet known.
It is reported that sleep patterns change as individuals age. Therefore, the question arises whether changes in sleep patterns in middle or late years increase the risk of frequent disease.
About this study
The current study utilizes the Whitehall II cohort, an ongoing study established in 1985 and includes 10,308 (6,895 males and 3,413 females) British civil servants. As 99.9% of participants were associated with the electronic health records of the National Health Service (NHS), relevant medical data were obtained from the service.
Self-report information on participants’ average weekend sleep duration was obtained during six data collection waves from 1985 to 2016. This information is classified by age (i.e., 50, 60, and 70). Jenkins' Sleep Problem Scale was used to assess sleep quality. Participants were asked about their sleep experiences such as difficulty sleeping, restless sleep, several waking times at night, and difficulty falling asleep.
In this study, the multiple incidence was defined as the presence of two or more chronic diseases among the 13 chronic diseases identified as of March 2019 based on the clinical examination of Whitehall.
study results
There were 7, and 864 participants with no frequent disease were 50 years old. In this group, 4,446 people suffered from the first chronic disease, 2,297 people developed a frequent disease, and 787 people died later.
It is observed that those who sleep less than five hours at age 50 have an increased risk of developing the first chronic disease compared to seven hours of sleep. Interestingly, more than nine hours of sleep have nothing to do with this transition.
The current prospective study proposes three key findings. First, short sleep time is associated with an increased risk of multiple diseases. This observation was accurate for both middle-aged and older participants. Short sleep time is also related to the first and subsequent frequent occurrences. However, it has nothing to do with mortality.
Secondly, the probability of sleeping for a long time at ages 60 and 70 is less likely to occur, and the incidence of multiple diseases is observed. However, this was not the case for the 50-year-old participant. Therefore, prolonged sleep at the age of 50 has nothing to do with disease progression.
Third, accelerometer-based sleep duration measurements in participants with an average age of 69 years confirmed the relationship between sleep duration and multiple incidence in participants aged 60 and 70 years.
Advantages and Limitations
The main advantages of this study include long follow-up time and repeated measurements of sleep duration in different age groups. In addition, using multi-state models allows for a deeper understanding of the relationship between sleep duration and disease processes.
A basic limitation of this study is that the number of participants in the long sleep duration category is that. Therefore, the authors failed to infer the incidence of multiple diseases in this group.Furthermore, the self-reported nature of the study increased the risk of outcome bias. The authors also point to the risk of reverse causality of undiagnosed disease in sleep measurements. The cohort contained a limited number of non-white participants, so the findings could not be generalized.
Conclusion
Current research strongly demonstrates the relationship between short sleep time and the development of multiple diseases. This observation is accurate for people in middle age or later years. Short sleep time at the age of 50 is associated with a higher risk of first chronic disease and subsequent frequent disease. Current research recommends good sleep time and quality for better health outcomes.
Journal Reference:
- Sabia, S. et al. (2022) Association for Sleep Duration and Multiple Disease Risks in the United Kingdom: 25-year follow-up of in the Whitehall II cohort study. Prolos Medical , 19 (10): e1004109.https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1004109 https://doi.org/10.1371/journal.pmed.1004109
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