Monday, March 10, 2025

New study links sleep debt and night shifts to increased infection risk among nurses

Taylor & Francis Group

A new study examining the effects of sleep patterns and shift work on the immune system has found that sleep debt and night shifts increase the risk of several common infections in nurses.

Modern society relies on shift work, which requires employees to work outside of traditional hours. While essential in sectors such as healthcare, growing evidence suggests that these work patterns may negatively impact worker’s health.

This study, which analysed self-reported data from 1,335 Norwegian nurses, found that shift work – particularly night shifts – was associated with a higher risk of several infections, including the common cold.

Published today in Chronobiology International, the peer-reviewed findings emphasise the importance of adequate sleep and shift management in reducing susceptibility to infection.

“These findings highlight the need for tailored interventions to reduce infection risks among healthcare workers,” says Siri Waage, senior author of the study, who is the coordinator at the Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Bergen.

“Sleep debt and irregular shift patterns, including night work, not only compromise nurses’ immune health but could also impact their ability to provide high-quality patient care.”

The researchers analysed data from the Survey of Shift work, Sleep and Health (SUSSH) study, collected in 2018. The participants – mostly female nurses (90.4%), with an average age of 41.9 years – reported their sleep duration, sleep needs, shift work patterns, and how often they had experienced specific infections over the past three months.

Statistical analyses, adjusted for factors such as age, gender, marital status, and childcare responsibilities, revealed a clear link between slept debt, night work and infection risk.

The study found that sleep debt, defined as the gap between sleep need and actual sleep duration, increased infection risk in a dose-dependent manner:

Nurses with moderate sleep debt (1-120 minutes less sleep than needed) had a 33% higher risk of the common cold, while those with severe sleep debt (more than 2 hours) had more than double compared to those with no sleep debt.

The risk of pneumonia/bronchitis was 129% higher for moderate sleep debt and 288% for severe sleep debt.

Both sinusitis and gastrointestinal infections also showed higher risks with increasing levels of sleep debt.

The analysis also revealed that night work was linked with an increased risk of the common cold, but was not associated with any of the other infections examined. In contrast, sleep duration and ‘quick returns’ (short intervals between consecutive shifts) were not associated with infection risk.

These findings suggest that ensuring sufficient sleep may help prevent infections, although further research is needed to determine cause-and-effect relationships.

The authors propose several strategies that might help reduce sleep debt and potentially lower infection risks among nurses in the future.

“Nurses could benefit from optimised shift patterns, such as limiting consecutive night shifts and allowing adequate recovery time between shifts,” adds co-author Professor Ståle Pallesen, whose research specialisms blend psychology and insomnia, at the Department of Psychosocial Science at University of Bergen.

“Raising awareness about the importance of sleep for immune health and encouraging regular health screening and vaccinations for healthcare workers may also be helpful.”

A key strength of this study is its large sample size and focus on predominantly female nurses over 30, making it well-suited to analysing associations between sleep patterns and infection risk in this group. However, the findings may not be generalisable to men, younger nurses, other professions, or those with different shift work schedules.

Additionally, since data collection took place in the spring, outside the typical flu season, infection rates may have been lower than if the survey had been conducted in winter.

Journal

Chronobiology International

DOI

10.1080/07420528.2025.2455147

Method of Research

Survey

Subject of Research

People

Article Title

Night work and sleep debt are associated with infections among Norwegian nurses

Article Publication Date

10-Mar-2025

Less than half of US parents think they have accurate information about bird flu

National Poll: 2 in 5 parents wish the government was doing more to prevent a bird flu outbreak; 1 in 3 have taken action to protect their family against it

Michigan Medicine - University of Michigan

National poll on parent perceptions of bird flu — image:
Parent confidence in state and federal government's ability to handle bird flu
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Credit: Sara Schultz, University of Michigan Health C.S. Mott Children's National Poll on Children's Health

With soaring egg prices and ongoing bird flu headlines, many parents are uncertain about the risks and facts surrounding the virus, a national poll suggests.

Most parents say they don’t know if there have been cases of bird flu in their state, and less than half feel that they are able to find accurate and current information about it, according to the University of Michigan Health C.S. Mott Children’s Hospital National Poll on Children’s health.

“Many parents may hear about bird flu in the news but don’t feel well-informed or know if they should be taking action to protect their families,” said Mott Poll Co-Director Sarah Clark, M.P.H.

“This report highlights the challenge for parents to keep track of an emerging health situation and understand its potential threat to their child’s health.”

Bird flu, or H5N1, which was reported in the U.S. in March 2024, is widespread in wild birds worldwide that transmit infection to poultry and dairy cows. H5N1 infections in humans have so far been limited to those who come in close contact with infected animals, including U.S. farmworkers.

While the current public health risk has been deemed low, with no evidence of transmission from human to human, the outbreak has increased public concern about the potential for broader transmission.

Previous outbreaks of H5N1, including one in 2003-2005, highlight this possibility.

Steps parents believe protect families from avian flu

While one in five parents say the media is making too big a deal about the virus, two in five wish the government was doing more to prevent an outbreak, according to the nationally representative report based on responses from 2,021 parents of children aged 18 and under.

Another one in three parents have taken action to protect their family against bird flu, the poll suggests, but not all strategies are evidence-based.

A little less than a quarter of parents say they’re being more careful about general hygiene while 13% are more cautious handling eggs, chicken and beef. Another 12% are avoiding contact with birds and other wild animals while 7% are eating less eggs, chicken, and beef.

“Some parents indicated they have cut back on eating poultry products like eggs and chicken,” Clark said. “However, as long as eggs and meat are fully cooked, there’s no evidence that bird flu is spread through these products.”

Among the 68% of parents who haven’t taken preventive actions, their main reasons are that they already have good hygiene practices, don’t know the recommendations or don’t feel at risk.

Confidence in containing the virus

Nearly half of parents rate themselves as very concerned about the rising cost of eggs and meat associated with bird flu, and over a quarter are very concerned about bird flu spreading from animals to humans or humans to humans.

A third of parents, however, weren’t confident in the government’s ability to contain bird flu.

Less than 20% of parents expressed high confidence in the state or federal government’s ability to remove infected animals or animal products from the food supply while 22% are very confident the government will be able to inform people about which products should be recalled or thrown away.

“There appears to be a gap in public confidence when it comes to the national response to bird flu,” Clark said. “Misinformation and uncertainty can fuel anxiety, so it’s critical that health officials communicate transparently about containment efforts and food safety to reassure families.”

Keeping up with evolving information can be challenging with parents polled saying their main sources are news reports, followed by social media and internet searches. Fewer got information from family or friends, a government agency or healthcare providers

Reinforcing preventive health measures

Bird flu is an influenza A virus that produces a gastrointestinal infection, causing death from diarrhea and respiratory distress. The version currently circulating in the U.S., known as H5N1 2.3.4.4b, is highly lethal

Because H5N1 is very contagious, it’s become standard practice to cull the entire flock or herd to prevent the spread once it’s discovered in an animal. Millions of chickens have been culled as a preventive measure, contributing to the increased price of eggs.

While the risks of bird flu are greatest for individuals who work with farm animals and their families, Clark says, the situation presents an opportunity for parents to reinforce the principles of good hygiene with their children.

Children should be cautioned to avoid dead animals, she says, and try to avoid animal droppings, which can be hard to detect in yards or sandboxes.

“Parents should teach their child to keep their hands away from their face and remind them to wash their hands with soap and water after touching birds and other animals at a petting zoo or a neighbor’s backyard chicken coop,” Clark said.

Clark recommends that parents practice good hygiene with food, such as cooking eggs and meat to recommended temperatures, and choosing milk and other dairy products that are pasteurized to kill germs.

The two faces of liquid water

Computer simulations reveal how water separates into high-density and low-density liquids

University of California - San Diego

molecular dynamics of liquid water — image:
simulation of the molecular dynamics of supercooled water.
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Credit: Pasesani group./ UC San Diego

Water is unique. It is one of the only substances that can exist in nature as a solid, liquid and gas at the same time under ambient conditions (think of solid ice over a pond, which is liquid underneath while storm clouds float overhead). It is also one of the only substances whose solid form is less dense than its liquid — this is why ice floats.

Now scientists from the University of California San Diego have uncovered a key finding to another unique property: at high pressure and low temperature, liquid water separates into two distinct liquid phases — one high-density and one low-density. Their work appears in Nature Physics.

UC San Diego Professor of Chemistry and Biochemistry Francesco Paesani works at the intersection of chemistry, physics and computer science to build models based on the fundamentals of physics that can address problems in chemistry. By using machine learning techniques and algorithms from computer science, his group is able to create realistic molecular models that match what people can measure experimentally.

“Our water model is so realistic you can almost drink it,” Paesani said.

Most liquids are homogenous — it all flows together and you can’t distinguish one liquid molecule from the next. Indeed, this is mostly true of water. However, in 1992 researchers theorized that at a certain temperature and pressure, liquid water would reach a critical point at which it would no longer be homogenous.

Paesani’s team conducted simulations that revealed the critical point at which the temperature is low enough (198 Kelvin or -103 Fahrenheit) and the pressure is high enough (1,250 atmospheres) for water to spontaneously separate into high-density and low-density liquids.

At this critical point, water exhibits wild oscillations between high- and low-density phases. Below this pressure, water returns to its low-density phase; above it, it shifts entirely to the high-density phase. This is an unexpected phenomenon unfolding at the molecular level.

Data-driven, many-body potentials

The 1992 simulation was crude. Since then, researchers have tried to create this spontaneous separation experimentally, but without success. Over the past three decades, advancements in computational modelling have made more detailed, accurate simulations possible — particularly the advent of data-driven many-body potentials, in which Paesani’s group specializes.

The data-driven many-body model of water (MB-pol) developed by the Paesani group is trained on high-level quantum mechanical calculations (data-driven) and rather than calculating the energy of an entire system at once, they deconstruct energy in terms of individual contributions (many-body). These reference energies are fed into a machine learning model that is then able to provide realistic simulations of water across the entire phase diagram.

Paesani explains the MB-pol model in this way: a person alone in a room behaves a certain way. If someone else enters the room, the first person’s behavior changes to accommodate the second person. If a third person enters, the dynamic of the first two changes. On and on until there are so many people in the room that the addition of one more does not significantly impact the behavior of any single person.

This is how MB-pol works. In the short range, there are quantum mechanical effects that directly modify the behavior of the water molecules, just as one person influences the behavior of another. However, at a certain point, the effects are averaged out over the entire system, just as adding one more person to an already crowded room doesn’t impact the behavior of another individual.

“Quantum mechanical simulations can be extremely expensive. You might be able to calculate the energies of five or six water molecules. Our method, using MB-pol and machine learning, allows us to run simulations for up to several microseconds,” stated Paesani. “This is something computational molecular scientists have dreamed about for a long time.”

However, the discovery didn’t come easy. Running simulations for this research took nearly two years of non-stop calculations using some of the world’s most powerful supercomputers, including Expanse at the San Diego Supercomputer Center, which is a pillar of UC San Diego’s new School of Computing, Information and Data Sciences.

In the future, as technology develops, Paesani hopes this research might be used to devise synthetic liquids that undergo a similar liquid-liquid transition as water, but can do so in everyday conditions. Porous liquids that can move from low to high density would behave similarly to sponges, and could be used to capture pollutants or aid in water desalinization.

“The simulation took almost two years, so this is a really exciting accomplishment,” stated Paesani. “I think our estimate is very realistic. Now it’s up to the experimental researchers to see whether our predictions are correct.”

Currently, recreating these conditions in a laboratory remains a challenge. However, nanodroplet technology could offer a way forward by creating tiny water droplets that generate high internal pressure through surface tension, potentially leading to experimental confirmation of this phenomenon.

For now, this discovery offers the most accurate prediction yet of a phenomenon scientists have long suspected, but never directly observed. And when that day comes, it may change the way we think about water forever.

Full list of authors: Yaoguang Zhai, Sigbjørn Løland Bore, Francesco Paesani (all UC San Diego), and Francesco Sciortino (Sapienza Università di Roma).

This research was supported in part by the Air Force Office of Scientific Research (FA9550-20-1-0351) and the National Science Foundation (CHE230052).