People who reported sleeping 5 hours or less a night had a higher risk of multiple chronic diseases in the future, a longitudinal study in England showed.
Healthy 50-year-olds who slept 5 or fewer hours a night had a 30% greater risk of future multimorbidity over 25 years compared with those who slept 7 hours (HR 1.30, 95% CI 1.12-1.50, P<0.001), according to Séverine Sabia, PhD, of Université de Paris and University College London, and co-authors.
Short sleep durations at age 60 (HR 1.32, 95% CI 1.13-1.55, P<0.001) and 70 (HR 1.40, 95% CI 1.16-1.68, P<0.001) also were associated with higher multimorbidity risk, the researchers reported in .
"The importance of sleep has been shown for specific diseases, such as cardiovascular disease or diabetes," Sabia told Ƶ. "However, in real life, chronic diseases often co-occur at older age. It was unknown whether sleep duration is associated with multimorbidity and whether this link is similar depending on age at sleep measure."
"Sleep plays an important role in the regulation of our body functions, including the regulation of endocrine, metabolic, and inflammatory systems," Sabia said. "When dysregulated, these functions are associated with increased risk of chronic disease."
The researchers followed 7,864 participants in the cohort, an ongoing prospective study established in 1985 of people who worked in the British civil service. Participants were free of multimorbidity at baseline; about a third (32.5%) were women and 90.1% were white.
Self-reported sleep duration was assessed six times between 1985 and 2016. For this analysis, sleep duration data were extracted at ages 50, 60, and 70. At age 50, 544 people reported sleeping 5 or fewer hours, 2,562 slept 6 hours, 3,589 slept 7 hours, 1,092 slept 8 hours, and 77 slept 9 hours or more.
Multimorbidity was defined as having two or more of 13 chronic diseases that included diabetes, cancer, coronary heart disease, stroke, heart failure, chronic obstructive pulmonary disease, chronic kidney disease, liver disease, depression, dementia, other mental disorders, Parkinson's disease, and arthritis.
Sleeping 9 hours or more at age 60 (HR 1.54, 95% CI 1.15-2.06, P=0.003) and age 70 (HR 1.51, 95% CI 1.10-2.08, P=0.01) was associated with incident multimorbidity, but this was not true at age 50 (HR 1.39, 95% CI 0.98-1.96, P=0.07).
Over a mean follow-up of 25.2 years, 4,446 people developed a first chronic disease, 2,297 progressed to multimorbidity, and 787 subsequently died.
Sleeping 5 hours or less at age 50 was associated with an increased risk of a first chronic disease (HR 1.20, 95% CI 1.06-1.35, P=0.003) and with subsequent multimorbidity, but not mortality. Sleeping 9 hours or more was not associated with these changes.
Accelerometer data were available for a group of 3,920 participants at a 2012 assessment. "The shape of the association between accelerometer-assessed sleep duration and incident multimorbidity was similar to that observed with self-reported sleep duration," Sabia and colleagues noted.
Limitations included the use of self-reported sleep data, the potential for reverse causality, and the small proportion of non-white participants in the study. Whitehall II participants all were employed when they were recruited and may be healthier than the rest of the population.
"Over the past decade, it has been observed that people tend to sleep less," Sabia pointed out.
"We listen to our body and eat when we are hungry," she said. "It's also important to sleep when we feel it is right and have habits that promote good sleep."
Disclosures
This project is part of the National Institute on Aging (NIA) at the NIH. Researchers were supported by grants from the NIA, the U.K. Medical Research Council, the British Heart Foundation, the Wellcome Trust, and the French National Research Agency.
Sabia and colleagues had no competing interests.
Primary Source
PLoS Medicine
Sabia S, et al "Association of sleep duration at age 50, 60, and 70 years with risk of multimorbidity in the UK: 25-year follow-up of the Whitehall II cohort study" PLoS Med 2022; DOI: 10.1371/journal.pmed.1004109.