Sleep problems tied to risk of COVID-19 outcomes
A cross-sectional analysis has found an association between insomnia, poor sleep quality, and extremes of sleep duration and increased COVID-19 infection and hospitalization.
“[Using] data from the first four 2022 waves of the COPE* Initiative, [we found that] insomnia and poor sleep quality were associated with a greater risk of having had a COVID-19 infection. The association was stronger for poor sleep quality than for insomnia,” said the researchers.
“Poor sleep quality, but not insomnia alone, was also linked to greater likelihood of COVID-19-related hospitalization,” they continued.
The total study sample comprised 19,926 US adults (mean age 46.3 years, 51 percent female). Of these, 40 percent reported a previous COVID-19 infection. The prevalence of COVID-19 hospitalization was 2.9 percent. [Am J Med 2023;136:780-788.e5]
After adjusting for self-reported sleep duration and excluding participants who reported COVID-19-related sleep problems, poor sleep quality was associated with COVID-19 infection (adjusted odds ratio [aOR], 1.16; p<0.01) and hospitalization (aOR, 1.50; p<0.001).
Extremes of sleep duration also matter
Based on hourly sleep duration and after excluding patients with current COVID-related sleep problems, compared with a reference sleep duration of 7–8 hours, shorter sleep hours (ie, 3–6 hours) were associated with a greater odds of previous COVID-19 infection, with adjusted ORs ranging between 1.12 and 1.17 (fully adjusted model). A similar effect was seen in the longer sleep category, specifically among those who slept for 12 hours (aOR, 1.61; p<0.01).
When stratifying the results into short (≤6 hours), normal (7–8 hours), and long (≥9 hours) sleep durations, only short sleep duration was tied to previous COVID-19 infection after adjusting for demographics (aOR, 1.17; p<0.001), comorbidities (aOR, 1.10; p<0.05), and socioeconomic factors (aOR, 1.14; p<0.001).
The researchers attributed the greater odds of COVID-19 infection among short sleepers to the impaired immune responsiveness tied to short sleep duration. [Neuropsychopharmacology 2017;42:129-155] Moreover, inadequate sleep has been shown to blunt immune response to vaccines. [Sleep 2012;35:1063-1069; JAMA 2002;288:1471-1472; Psychosom Med 2003;65:831-835]
“[A]dditional research is needed to elucidate the mechanisms responsible for the associations between both short and long sleep duration and disease risk,” said the researchers.
Healthy sleep practices encouraged
It remains unclear why sleep problems are associated with COVID-19 infection and hospitalization. But one potential pathway is the elevated stress levels associated with sleep issues, with subsequent sympathetic nervous system activation and cortisol increase, the researchers noted. [Sleep Med Rev 2010;14:9-15]
“This increases release of norepinephrine. It has been suggested that such adrenergic signalling can suppress transcription of antiviral interferon genes, potentially increasing susceptibility to viral infection,” they explained. Moreover, increased sympathetic nervous system activity may induce a state of chronic inflammation that could subsequently weaken immune response. [Nat Med 2019;25:1822-1832]
Of note, a majority of survey respondents with suspected or confirmed COVID-19 reported having insomnia at some point in their illness, with 40 percent having persistent symptoms >2 years post infection. [EClinicalMedicine 2021;38:101019] “It is thus possible that COVID-19 infection induced sleep problems rather than vice-versa. However, [this might not entirely explain] our findings because the exclusion of participants who endorsed current COVID-19-related sleep problems did not fundamentally alter our observations,” the researchers said.
“Taken together, the findings provide evidence that a public health approach encouraging healthy sleep practices will lessen the impact of the COVID-19 pandemic,” the researchers concluded.