Sleep Duration Affects Risk for Chronic Disease and Multimorbidity

Short sleep duration in midlife-to-late life correlates with an increased risk for multimorbidity with chronic diseases, according to study findings published in PLoS Medicine.

Researchers in the United Kingdom conducted a 25-year follow-up until March 2019 of the prospective Whitehall II cohort study performed in 1985, which obtained data on people employed in the London offices of the British Civil Service (N=10,308; 6895 men; 3413 women; mean age, 35-55 years).

Sleep assessments, particularly sleep duration, occurred 6 times between 1985 and 2016. These researchers analyzed sleep duration in participants ages 50 (n=7864), 60 (n=6848), and 70 (n=5546), and examined the relationship of sleep duration with multimorbidity. They defined multimorbidity as having 2 or more of 13 different chronic diseases, including:

1. diabetes,
2. cancer,
3. coronary heart disease,
4. stroke,
5. heart failure,
6. chronic obstructive pulmonary disease,
7. chronic kidney disease,
8. liver disease,
9. depression (or use of antidepressants),
10. dementia,
11. mental disorders, other than depression and dementia,
12. Parkinson disease, and
13. arthritis/rheumatoid arthritis.

They found that 7864 people aged 50 (32.5% women) remained free of multimorbidities. The following lists the percentage of participants who slept between 5 hours or less to 9 hours or more:

• Approximately 6.9% of participants slept 5 hours or less
• 32.6% of participants slept 6 hours, 45.6% slept 7 hours
• 13.9% of participants slept 8 hours
• 1% of participants slept 9 or more hours

Compared with participants sleeping 7 hours, those sleeping 5 hours or less demonstrated higher risk for multimorbidity (hazard ratio [HR], 1.30; 95% CI, 1.12-1.50; P <.001). The researchers observed similar multimorbidity trends in people with shorter sleep duration at ages 60 (HR, 1.32; 95% CI, 1.13-1.55; P <.001), and 70 (HR, 1.40; 95% CI, 1.16-1.68; P <.001).

Sleep duration of 9 hours or longer also correlated with incidence multimorbidity at age 60 (HR, 1.54; 95% CI, 1.15-2.06; P =.003) and at age 70 (HR, 1.51, 1.10-2.08; P =.01), but not at age 50 (HR, 1.39; 95% CI, 0.98-1.96; P =.067). Notably, sleep duration of any length did not correlate with increased mortality among people with chronic diseases.

Among the 7217 participants in the age 50 group without chronic disease, 4446 developed 1 chronic disease, 2297 subsequently developed multimorbidity, and of this group, 787 died.

Sleep duration of 5 hours or less was associated with an increased risk for first chronic disease (adjusted HR [aHR], 1.20; 95% CI, 1.06-1.35; P =.003) and subsequent multimorbidity (aHR, 1.21; 95% CI, 1.03-1.42; P =.021), compared with sleep duration of 7 hours.

“In this study, we observed short sleep duration to be associated with risk of chronic disease and subsequent multimorbidity but not with progression to death,” the researchers stated. “These findings support the promotion of good sleep hygiene in both primary and secondary prevention by targeting behavioral and environmental conditions that affect sleep duration and quality,” they added.

There are several study limitations that warrant mention. These include the use of self-reported sleep durations, which introduced reporting bias; availability of sleep quality only in people ages 60 and 70; small sample size in the longer sleep duration category; and the likelihood of healthier individuals being recruited to the study compared with the general population given their employment status. Additionally, the small number of non-White participants and potential reverse causality due to underlying undiagnosed conditions that impact sleep duration may also limit the generalizability of results.

This article originally appeared on Neurology Advisor