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More sleep at night, fewer or no sleep problems, and low levels of professional burnout were associated with a lower risk of developing COVID-19 among healthcare workers considered to be at high risk for exposure to patients with COVID-19, new evidence reveals.
For each additional hour of sleep at night, for example, risk for COVID-19 dropped by 12% in a study of 2844 frontline healthcare workers.
Furthermore, those who reported experiencing work-related burnout every day were 2.6 times more likely to report having COVID-19, to report having COVID-19 for a longer time, and to experience COVID-19 of more severity.
“This study underscores the importance of nonhygiene-related risk factors for COVID-19 and supports a holistic approach to health ― including optimal sleep and job stress reduction to protect our healthcare workers from this and future pandemics,” senior author Sara Seidelmann, MD, told Medscape Medical News.
Dr Sara Seidelman
Seidelmann and colleagues note, “Our findings add to the literature that sleep duration at night, sleep problems and burnout may be risk factors for viral illnesses like COVID-19.”
This is the first study to link COVID-19 risk to sleep habits ― including number of hours of sleep at night, daytime napping hours, and severe sleep problems ― among healthcare workers across multiple countries.
The study was published online March 22 in BMJ Nutrition, Prevention and Health.
The researchers surveyed healthcare professionals in specialties considered to place personnel at high risk for exposure to SARS-CoV-2: critical care, emergency care, and internal medicine.
Interestingly, the association between sleep and burnout risk factors and COVID-19 did not vary significantly by specialty. “We didn’t detect any significant interactions between age, sex, specialty, or country,” said Seidelmann, assistant professor of clinical medicine at Columbia University College of Physicians and Surgeons, New York City, and an internist at Stamford Hospital, Stamford, Connecticut.
In addition to the 12% lower risk associated with each additional hour of sleep at night, each 1 additional hour of daytime napping was linked with a 6% increased risk for COVID-19 in an adjusted analysis (odds ratio [OR], 1.06; 95% CI, 1.01 –– 1.12).
Daytime napping slightly increased risk for COVID-19 in 5 of the 6 countries included in the study: France, Germany, Italy, the United Kingdom,and the United States. In contrast, in Spain, napping had a nonsignificant protective effect.
The survey asked healthcare workers to recall nighttime sleep duration, sleep disorders, and burnout in the year prior to onset of the COVID-19 pandemic.
“Significant, Close Contact” With COVID-19?
Lead author Hyunju Kim, NP, Seidelmann, and colleagues conducted the population-based, case-control study from July 17 to September 25, 2020. They identified healthcare workers from the Survey Healthcare Globus (SHG) network.
Of the respondents, 72% were men. The mean age of the participants was 48 years, and the study population was 77% White, 12% Asian, 6% mixed, 2% Black, and 1% other.
The 568 healthcare workers considered to have COVID-19 were classified on the basis of self-reported symptoms. Control participants had no symptoms associated with COVID-19.
All 2844 participants answered yes to a question about having “significant close contact” with COVID-19 patients in their workplace.
Compared to reporting no sleep problems, having three such problems ― difficulty sleeping at night, poor sleep continuity, and frequent use of sleeping pills ― was associated with 88% greater odds of COVID-19 (OR, 1.88; 95% CI, 1.17 – 3.01).
Having one sleep problem was not associated with COVID-19.
More Burnout, Greater Risk
The healthcare workers reported the severity of any work-related burnout. “There was a significant dose-response relationship between frequency of burnout and COVID-19,” the researchers note.
Those who reported having burnout rarely or weekly had a 1.3 to 1.4 greater chance of reporting COVID-19 compared to those who reported having no burnout, for example.
In addition, reporting a high level of burnout was linked to about three times the risk for having COVID-19 of longer duration and of greater severity.
What drives the association between sleep problems, burnout, and higher risk for COVID-19 and severe COVID-19 remains unknown.
“The mechanism underlying these associations isn’t clear, but suboptimal sleep, sleep disorders, and stress may result in immune system dysregulation, increased inflammation, and alterations in hormones such as cortisol and melatonin that may increase vulnerability to viral infections,” Seidelmann said.
“There appears to be a bi-directional relationship between sleep problems and burnout as well as extensive evidence of the link between sleep and immunity,” Sofia Pappa, MD, PhD, told Medscape Medical News when asked to comment on the study.
“Disturbed sleep and insomnia have been associated with an increased probability of respiratory infections such as common cold and pneumonia, and several studies have found a relationship between sleep duration and vaccination response,” added Pappa, honorable senior lecturer at Imperial College London and consultant psychiatrist and research lead at West London Mental Health NHS Trust, United Kingdom.
Strengths and Limitations
Using a large network of healthcare workers in the early phase of the pandemic is a strength of the study. How generalizable the findings are outside the SHG database of 1.5 million healthcare workers remains unknown.
Another limitation was reliance on self-reporting of COVID-19 patient exposure, outcomes, and covariates, which could have introduced bias.
“However,” the researchers note, “health care workers are likely a reliable source of information.”
Insomnia a Common Challenge
A 2020 meta-analysis examined the effect of insomnia and psychological factors on COVID-19 risk among healthcare workers. Lead author Kavita Batra, PhD, and co-author Manoj Sharma, MBBS, PhD, both of the University of Nevada, Las Vegas (UNLV), found that the pooled prevalence of insomnia was almost 28%.
Dr Manoj Sharma
“The recent six-country study by Kim and colleagues also underscores this relationship between lack of sleep and having higher odds of COVID-19 infection,” Sharma, professor of social and behavioral health in the UNLV Department of Environmental and Occupational Health, School of Public Health, told Medscape Medical News when asked to comment.
More research is warranted to learn the direction of the association, he said. Does reduced sleep lower immunity and make a healthcare worker more susceptible to SARS-CoV-2 infection, or does the anxiety associated with COVID-19 contribute to insomnia?
“Practicing sleep hygiene is a must not only for health workers but also for everyone,” Sharma added. Recommendations include having fixed hours of going to bed, fixed hours of waking up, not overdoing naps, having at least 30 minutes of winding down before sleeping, having a dark bedroom devoid of all electronics and other disturbances, avoiding smoking, alcohol, and stimulants (such as caffeine) before sleeping, and practicing relaxation right before sleeping, he said.
“It is hard for some healthcare workers, especially those who work night shifts, but it must be a priority to follow as many sleep hygiene measures as possible,” Sharma said. “After all, if you do not take care of yourself how can you take care of others?”
Seidelmann, Batra, and Sharma have disclosed no relevant financial relationships.
BMJ Nutr Prev Health. Published online March 22, 2021. Full text
Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology and neurology. Follow Damian on Twitter: @MedReporter.