Human physiological processes rely heavily on sleep for correct functioning. A recent PLOS Medicine journal study determined the connection between sleep duration of older people, i.e., 50, 60, and 70 years of age, and the incidence of multimorbidity. Significantly, the study utilized follow-up data for twenty-five years for the evaluation.

Study: Association of sleep duration at age 50, 60, and 70 years with risk of multimorbidity within the UK: 25-year follow-up of the Whitehall II cohort study. Image Credit: kudla / Shutterstock

Lack of Evidence Related to Sleep Duration and Healthy State

Although several studies have indicated the connection between sleep duration and the manifestation of chronic diseases (e.g., cancer and heart problems) and mortality, the character of this association stays unclear.

When a couple of chronic condition prevails inside the same individual, it’s referred to as multimorbidity. Nonetheless, not many studies can be found regarding the association between multimorbidity and sleep duration. Moreover, whether sleep duration impacts health, manifests chronic conditions, and subsequent mortality is just not known.

Currently, older adults are really helpful 7 to eight hours of sleep; nevertheless, whether short or long sleep duration increases the chance for morbidity ought to be explored in future research. The underlying biological mechanisms related to short-duration sleep and the onset of comorbidities can be found; nevertheless, the impact of prolonged sleep on the manifestation of chronic conditions is just not well understood.

It has been reported that as a person gets older, the sleep pattern changes. Hence, the query arises if changes in sleep patterns in mid or later-life increase the chance of multimorbidity.

In regards to the Study

The present research utilized the Whitehall II cohort, an ongoing study established in 1985 comprising 10,308 (6,895 men and three,413 women) British civil servants. Since 99.9% of the participants were linked to UK National Health Service (NHS) electronic health records, relevant medical data were obtained from this service.

Self-reported information on the common week-night sleep duration of the participants was obtained at six data collection waves between 1985 and 2016. This information was categorized based on age, i.e., 50, 60, and 70 years of age. Jenkins’s sleep problems scale was used to evaluate sleep quality. Participants were asked about their sleep experiences, equivalent to troubled sleep, disturbed sleep, waking up several times at night, and difficulty falling asleep.

On this study, multimorbidity was defined because the presence of two or more chronic diseases out of thirteen identified based on the Whitehall clinical examinations as much as March 2019.

Flowchart for analyses on the association between sleep duration at age 50, 60, and 70 and risk of multimorbidity.

Study Findings

A complete of seven,864 participants who didn’t have multimorbidity were on the age of fifty years. Amongst this group, 4,446 developed the primary chronic disease, 2,297 progressed to multimorbidity, and 787 subsequently died. 

It was observed that in comparison with seven hours of sleep, those that slept lower than five hours at 50 years showed an increased risk of developing their first chronic disease. Interestingly, sleep duration above nine hours was not related to such transitions.

The present prospective study presented three key findings. First, short sleep duration was continuously linked to an increased multimorbidity risk. This statement was accurate for each middle-aged and older age group participants. Short sleep duration was also related to first disease onset and subsequent multimorbidity. Nonetheless, it was not linked with mortality.

Second, long sleep duration was less likely at 60 and 70 years of age, and an incidence of multimorbidity was observed. Nonetheless, this was not true for participants who were 50 years of age. Hence, long sleep duration at 50 years of age was not related to disease progression.

Third, the accelerometer-based sleep duration measurement undertaken in participants whose mean age was 69 years confirmed the connection between the sleep duration and incidence of multimorbidity at ages 60 and 70.

Strengths and Limitations

The key strengths of this study include the long follow-up period and repeated measurement of sleep duration of assorted age groups. Moreover, using multistate models provided more insight into the association of sleep duration with the course of the disease.

A fundamental limitation of this study is the small variety of participants within the long sleep duration category. In consequence, the authors did not conduct inference on this group regarding the incidence of multimorbidity. Moreover, the self-reporting nature of the study increased the chance of biased results. The authors also indicated the chance of reverse causality from undiagnosed conditions at sleep measures. The cohort contained a limited variety of non-white participants, so the findings couldn’t be generalized.

Conclusions

The present study strongly indicated the connection between short sleep duration and the event of multimorbidity. This statement is accurate for people of their mid or late life. Short sleep duration at age 50 was linked with the next risk of first chronic disease onset and subsequent multimorbidity. The present study really helpful good sleep duration and quality for higher health outcomes.