Insomnia may increase vulnerability to influenza-like illness, a novel finding that was revealed by the passive collection of biometric data from a smart bed.
The study of smart-bed sleepers found that there was a statistically significant correlation between a higher number of episodes of influenza-like illnesses (ILI) per year with longer duration compared to people without insomnia.
However, more research is needed to determine causality and whether insomnia may predispose to ILI or whether ILI affects long-term sleep behavior, the researchers note.
"Several lines of evidence make me think that it's more likely that insomnia makes one more vulnerable to influenza through pathways that involve decreased immune function," study investigator Gary Garcia-Molina, PhD, with Sleep Number Labs, San Jose, California, told Medscape Medical News.
Sleep disorders, including insomnia, can dampen immune function and an individual's ability to fight off illness, he noted.
The findings were presented at SLEEP 2023, the 37th annual meeting of the Associated Professional Sleep Societies.
Smart, Connected Devices
Pathophysiologic responses to respiratory viral infection affect sleep duration and quality in addition to breathing function. "Smart" and "connected" devices that monitor biosignals over time have shown promise for monitoring infectious disease.
In an earlier study, Garcia-Molina and colleagues found that real-world biometric data obtained from a smart bed can help predict and track symptoms of COVID-19 and other respiratory infections.
They showed that worsening of COVID-19 symptoms correlated with an increase in sleep duration, breathing rate, and heart rate and a decrease in sleep quality, as previously reported by Medscape Medical News.
In the new study, the researchers evaluated vulnerability to ILI in people with insomnia.
They quantified insomnia over time using the insomnia severity index (ISI). They quantified ILI vulnerability using an established artificial intelligence model they developed that estimates the daily probability of ILI symptoms from a Sleep Number smart bed using ballistocardiograph sensors.
Smart bed data — including daily and restful sleep duration, sleep latency, sleep quality, heart rate, breathing rate and motion level — were queried from 2019 (pre-COVID) and 2021.
A total of 1680 smart sleepers had nearly constant ISI scores over the study period, with 249 having insomnia and 1431 not having insomnia.
Data from both 2019 and 2021 show that smart sleepers with insomnia had significantly more and longer ILI episodes per year compared to peers without insomnia.
For 2019, individuals without insomnia had 1.2 ILI episodes on average, which was significantly less (P < .01) than individuals with insomnia, at 1.5 episodes. The average ILI episode duration for those without insomnia was 4.3 days, which was significantly lower (P < .01) in those with insomnia group, at 6.1 days.
The data for 2021 show similar results, with the no-insomnia group having significantly fewer (P < .01) ILI episodes (about 1.2) compared with the insomnia group (about 1.5).
The average ILI episode duration for the no-insomnia group was 5 days, which was significantly less (P < .01) than the insomnia group, at 6.1 days.
The researchers say their study adds to other data on the relationship between sleep and overall health and well-being. It also highlights the potential health risk of insomnia and the importance of identifying and treating sleep disorders.
"Sleep has such a profound influence on health and wellness and the ability to capture these data unobtrusively in such an easy way and with such a large number of participants paves the way to investigate different aspects of health and disease," Garcia-Molina Medscape Medical News.
Rich Data Source
Commenting on this research for Medscape Medical News, Adam C. Powell, PhD, president of Payer+Provider Syndicate, a management advisory and operational consulting firm, said "smart beds provide a new data source for passively monitoring the health of individuals."
"Unlike active monitoring methods requiring self-report, passive monitoring enables data to be captured without an individual taking any action. This data can be potentially integrated with data from other sources, such as pedometers, smart scales, and smart blood pressure cuffs, to gain a more holistic understanding of how an individual's activities and behaviors impact their well-being," said Powell, who wasn't involved in the study.
There are some methodological limitations to the study, he noted.
"While the dependent variables examined were the duration and presence of episodes of influenza-like illness, they did not directly measure these episodes. Instead, they calculated the daily probability of influenza-like illness symptoms using a model that received input from the ballistocardiograph sensors in the smart beds," Powell noted.
"The model used to calculate daily probability of influenza-like illness was created by examining associations between individuals' smart-bed sensor data and population-level trends in influenza-like illness reported by the Centers for Disease Control and Prevention," he explained.
Nonetheless, the findings are "consistent with the literature. It has been established by other researchers that impaired sleep is associated with greater risk of influenza, as well as other illnesses," Powell told Medscape Medical News.
Funding for the study was provided by the Sleep Number Corporation. Garcia-Molina and five co-authors are employed by the Sleep Number Corporation. Powell reports no relevant financial relationships.
SLEEP 2022: the 37th Annual Meeting of the Associated Professional Sleep Societies. Abstract 0368. Presented June 5, 2023.