Healthy sleep before being infected with SARS-CoV-2 infection and before and during the COVID-19 pandemic might protect against post–COVID-19 condition, or long COVID.
Study authors indicated that future research should evaluate if sleep health interventions might prevent PCC or improve its symptoms.
This study was conducted because the association of various healthy sleep dimensions with PCC hasn’t been examined.
The authors aimed to evaluate if multidimensional sleep health before and during the COVID-19 pandemic but before SARS-CoV-2 infection was linked to the risk of PCC.
PCC is characterized as people experiencing persistent COVID-19–related symptoms more than 4 weeks following infection and affects 20% to 70% of those infected with SARS-CoV-2. The COVID-19 pandemic amplified preexisting sleep disorder severity and the increased prevalence of sleep disturbances.
This was a prospective cohort study (2015-2021) that included Nurses’ Health Study II participants who said they tested positive for SARS-CoV-2 infection in a substudy series of COVID-19-related surveys between the dates of April 2020 and November 2021. Following exclusion of those who provided incomplete sleep health information and no response to a question regarding PCC, a total of 1979 women were included in the analysis.
First, sleep health was calculated before (June 1, 2015, to May 31, 2017) and early (April 1 to August 31, 2020) in the COVID-19 pandemic. Prepandemic sleep score was characterized according to 5 dimensions: morning chronotype (assessed 2015), 7 to 8 hours of sleep per day, low insomnia symptoms, no snoring, and no recurrent daytime dysfunction (all measured in 2017). The first COVID-19 substudy survey (submitted between April and August 2020) asked about average daily sleep duration and sleep quality for the past week.
Then, SARS-CoV-2 infection and PCC (4 weeks or more of symptoms) were self-reported during follow-up of 1 year. Comparisons were analyzed between June 8, 2022, and January 9, 2023, through the use of Poisson regression models.
Out of the 1979 participants indicating SARS-CoV-2 infection (mean age, 64.7 [SD, 4.6] years; 1979 [100%] female; and 1924 [97.2%] White vs 55 [2.8%] other races and ethnicities), 845 (42.7%) were frontline health care workers, and 870 (44.0%) contracted PCC. Those women who scored 5 (most healthy) had a 30% lower risk of developing PCC (multivariable-adjusted relative risk, 0.70; 95% CI, 0.52-0.94; P <.001), in contrast with women who had a prepandemic sleep score of 0 or 1 (least healthy).
Associations were not different by health care worker status. No or slight daytime dysfunction prepandemic and good sleep quality during the pandemic were independently associated with a lesser risk of PCC (relative risk, 0.83 [95% CI, 0.71-0.98] and 0.82 [95% CI, 0.69-0.99], respectively). Similar results were observed when PCC was defined as having 8 or more weeks of symptoms or as having continuing symptoms at the time of PCC assessment.
“A combined prepandemic sleep score comprising early chronotype, sleep duration of 7 to 8 hours per day, low insomnia symptoms, no self-reported snoring, and no frequent daytime dysfunction was inversely associated with risk of PCC,” said the study authors.
Furthermore, those who scored 5 on healthy sleep dimension had a 30% lower risk of PCC compared to those who scored a 0 or 1. In mutually adjusted models, the associations were mostly driven by daytime dysfunction.
Increased self-perceived sleep quality early in the COVID-19 pandemic was also associated with a lower risk of PCC. Notably, women who had consistently health sleep during both times possessed the lowest risk of PCC compared with those with consistently unhealthy sleep.
A few pathophysiologic pathways might underlie the study authors’ findings. The proinflammatory state might predispose people with poor sleep health to the occurrence of cytokine storms, that have been suggested to be involved in the multiorgan manifestations of PCC.
Several limitations were present in this study. One is that participants were women at middle age or older who were 97% White, restricting finding generalizability. Also, almost half of the participants were frontline health care workers, even though study authors did not discover differences in the observed associations of those who were frontline workers and who weren’t.
“Future research should investigate whether improving sleep health may prevent or alleviate PCC symptoms,” concluded the study authors.
Wang S, Huang T, Weisskopf MG, Kang JH, Chavarro JE, Roberts AL. Multidimensional sleep health prior to SARS-CoV-2 infection and risk of post–COVID-19 condition. JAMA Netw Open. Published online May 30, 2023. doi:10.1001/jamanetworkopen.2023.15885