Infection-linked cancers, breathing and reaction time: what the newest studies actually show

Two studies landed within hours of each other on 29 September. One measured how fast 35 adults pressed a space bar while breathing in and out. The other tried to count how much cancer worldwide starts with an infection.

They are different kinds of science, with different kinds of uncertainty. Reading them together is a useful exercise in what a digital health headline can and cannot carry, especially in a week when wearable health research kept appearing alongside them.

41 milliseconds, measured under the nostrils

Northwestern University published the respiration study on 29 September. The headline number: reaction time on an exhalation was faster than on an inhalation by an average of 41 milliseconds, which the university's news release describes as 1/25th of a second. Response speed during the pauses between breaths was also faster than inhalation, by 21 milliseconds.

The experiment, titled "Response speed is modulated by respiratory phase," appeared in iScience, published by Cell Press. Ken Paller, the James Padilla Professor of Psychology at Northwestern, is the senior author. The lead author is Erika M. Yamazaki, a former member of Paller's lab who has kept working with it since finishing her PhD.

The setup was deliberately plain. Participants completed a Psychomotor Vigilance Task, a common computer test in which you press the space bar as soon as a red square turns yellow. Thirty-five adults aged 18 to 33 did this while wearing a small device under the nostrils to measure airflow. Each person completed the task twice, once before and once after either a nap or an eight-hour sleep in the lab. According to Northwestern, this is the first experiment to measure response speed during all phases of respiration, including the pauses in between.

"By using a tangible and easy to understand task, we were able to show the relationship between respiration and cognition, which I hope people in a range of fields will find application for," Yamazaki said in the release. "Study of the brain and body connection is still a new field of research, which makes the study findings all the more exciting."

Paller was careful about the mechanism. "This study documents an important link between respiration and the brain systems for responding to environmental events," he said. "We don't yet know exactly how they are linked, but we suspect neurophysiological efficiency, because other studies have shown that various brain oscillations are synchronized with the rhythms of one's breathing."

That is the honest version of the finding: a measured timing difference, not an explanation for it. Northwestern says Paller's lab is now running related research funded by the National Institutes of Health and led by Yamazaki, focused on sleep apnea. Harmful breathing pauses during sleep, the release notes, are often under-diagnosed and not adequately treated. The researchers hope noninvasive strategies for improving sleep, an approach sometimes called sleep engineering, can offset some of the consequences of poor sleep.

2.3 million cancer cases traced to infections

Also on 29 September, CBC News reported on a paper published Monday in The Lancet Oncology by researchers at the International Agency for Research on Cancer, an arm of the World Health Organization. The team estimated that infections caused 2.3 million new cancer cases in 2024, which CBC describes as 12 per cent of all new cases, or roughly one in eight.

The largest single contributor was the bacterium Helicobacter pylori, which can raise the risk of stomach cancer and accounted for 760,000 cases, predominantly in eastern Asia. Human papillomavirus came close behind at nearly 750,000 new cases globally, with high rates in sub-Saharan Africa. HPV causes 100 per cent of cervical cancer cases, according to CBC, along with anal, vulvar, vaginal, penile and some head and neck cancers. Hepatitis B and hepatitis C were also linked to a significant share of liver cancer cases.

The methodology matters here, because the number is an estimate rather than a count. Researchers first determined which infections cause cancer, then calculated what fraction of those cancers can be tied to specific infections, then applied those fractions to global databases of new cancer cases. For the first time, the team expanded its list to include 16 additional cancers.

Gary Clifford, a cancer epidemiologist and study co-author based in Lyon, France, told CBC that the underlying science has moved. "There's been new infectious agents identified in this time as being cancer-causing, and even the infectious agents that we knew about in the past, the evidence has increased about the number of different cancers that they can cause," he said.

Among the additions: HIV and its link to cervical cancer, and Merkel cell polyomavirus, a very rare virus that can lead to an aggressive form of skin cancer. Epstein-Barr virus was linked to about 260,000 cases in 2024, and can lead to nasopharyngeal cancer, some gastric cancers and Hodgkin's lymphoma. "That's quite a big burden of cancer caused by Epstein-Barr virus that was not counted in the past, but is now recognized," Clifford said. CBC notes that EBV is also a key risk factor for multiple sclerosis, and that unlike some other infections with vaccines or antibiotic treatments, there are no available tools to fight it.

"The fact that we're seeing Epstein-Barr has caused all these chronic diseases, it's increasingly becoming a target that people need to focus on for prevention," Clifford said.

The regional split is stark. High-income countries that built screening and vaccination programs over recent decades are doing much better than lower- and medium-resourced countries where access to prevention and treatment is limited. "We really still have a lot of work to do implementing things that we know work and we've known for a long time but haven't really made it into all populations in the world," Clifford said.

In North America the burden is much lower, with H. pylori and HPV the most common sources. In Canada, a 2019 study put the share of cancers attributable to infections at four per cent. Karena Volesky, an epidemiologist in Montreal who led the Canadian research team while at McGill University, told CBC the new global numbers show how important each of the 12 infections is.

Where wearables fit, and where they do not

Neither study tests a wristband. The Northwestern work used airflow sensors under the nose in a lab setting, and the cancer estimates come from epidemiological modelling, not from consumer devices. That has not stopped a steady flow of wearable health studies from appearing around them.

Recent items flagged in the research press include work in Microsystems & Nanoengineering on broadband wearable acoustic sensing for continuous cardiopulmonary monitoring, published 29 September, and a study reported by Newswise on 30 September about wearable AI forecasting prolonged sitting in women with chronic pelvic pain. Neither is part of the two papers above, and neither should be read as a follow-up to them.

What the pairing does illustrate is the difference in evidence weight. A 41-millisecond reaction-time difference is a small, directly measured effect in a lab sample of 35 people. A 2.3 million case estimate is a large modelled figure built on assumptions about causation and coverage. Both are legitimate; they answer different questions, and they carry different error bars.

The guidance gap researchers keep running into

A third study published in the same window deals with neither breath nor cancer, but with how researchers themselves handle AI tools. Nieman Journalism Lab reported on 28 September on a paper in Information, Communication and Society titled "Guidance over guidelines? Unpacking the uses and concerns of generative AI in communication science."

Researchers from National Yang Ming Chiao Tung University in Taiwan, the University of Amsterdam and Utrecht University surveyed more than 1,100 communication scholars across 77 countries and held four focus group discussions. The study reports that nearly 70 per cent of respondents had already used generative AI in at least one research-related task, while most also considered AI use inappropriate for most research tasks. Just over half said AI use was appropriate for writing texts (55 per cent) and generating code (50.4 per cent). No consensus emerged on what counts as ethical use.

Without institutional guidance, researchers set their own standards, and the study's authors argue this produces stigma. Using AI may look like cutting corners; disclosing it may make journals treat the work as less credible. The authors call this tension a transparency paradox, and the resulting feeling "AI shame."

"Simply forbidding the use of genAI, or pretending that it is not being used, is neither sustainable nor constructive," the authors write.

Their recommendation is a disclosure-positive culture in communication research, with journals and institutions requiring researchers to say at which stages of the work they used generative AI. Hannes Cools, one of the researchers, summarised the findings in a thread on Bluesky on 28 September, describing it as the first systematic, field-wide, international empirical investigation of generative AI practices in communication research.

For anyone reading health and technology studies this week, the three papers point in the same direction in one respect: the interesting part is usually the method. Under-nostril airflow, epidemiological modelling and a 1,138-person survey are not interchangeable evidence, and none of them is a product.