Infection study reframes cancer risk as wearable makers chase digital health funding

The finding landed on 29 September, when CBC News reported the figures. It is the newest hard number in a week otherwise dominated by hardware claims, pilot studies and funding talk rather than population-scale evidence.

That gap matters for anyone tracking digital health. Wearables keep getting better at measuring the body: respiration, heart rhythm, sleep, movement. What they are not yet doing, on the evidence in this dossier, is producing the kind of burden estimates that change screening programmes or vaccine budgets. The cancer study did that with a spreadsheet, not a sensor.

What the IARC team counted

Researchers at the International Agency for Research on Cancer, an arm of the World Health Organization, linked 2.3 million new cancer cases in 2024 to infectious agents. That is 12 per cent of all new cases, or one in eight. The largest single contributor was the bacterium Helicobacter pylori, which accounted for 760,000 cases, predominantly in eastern Asia. Human papillomavirus followed with nearly 750,000 cases and high rates in sub-Saharan Africa. Hepatitis B and hepatitis C were also linked to a significant number of liver cancer cases.

For the first time, the team expanded its list to include 16 additional cancers, among them HIV's link to cervical cancer and Merkel cell polyomavirus, a rare virus tied to an aggressive skin cancer. Epstein-Barr virus was linked to about 260,000 cases in 2024, including 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," said Gary Clifford, a cancer epidemiologist and study co-author based in Lyon, France, according to CBC.

"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.

The regional split is stark. High-income countries with established screening and vaccination programmes are doing much better than lower- and medium-resourced countries where access to prevention and treatment is limited. In North America, the burden of cancer-causing infections is lower, but H. pylori and HPV remain the most common sources. In Canada, a 2019 study estimated the rate of cancers attributable to infections at four per cent, a figure led by epidemiologist Karena Volesky while at McGill University.

Meanwhile, the sensor papers keep coming

On the same day, Northwestern University put out a study with a much smaller sample and a much narrower claim. Neuroscientists found that response speed on an exhalation is faster than on an inhalation by an average of 41 milliseconds, or 1/25th of a second. Response speed during pauses between breaths was faster than inhalation by 21 milliseconds.

The work, published in the journal iScience, is the first experiment to measure response speed during all phases of respiration, including the pauses. Thirty-five adults aged 18 to 33 completed a Psychomotor Vigilance Task, pressing a space bar when a red square turned yellow, while wearing a device under the nostrils to measure airflow. Each participant did the task twice, once before and once after a nap or an eight-hour sleep in the lab.

"This study documents an important link between respiration and the brain systems for responding to environmental events," said Ken Paller, the study's senior author and a psychology professor at Northwestern. "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 careful language, and it should be read as such. A 41-millisecond effect in 35 young adults is a lab result, not a clinical tool. Paller's lab is now working on related research funded by the National Institutes of Health and led by lead author Erika M. Yamazaki, focused on sleep apnea, a condition the researchers note is often under-diagnosed and inadequately treated.

The money and the guidance problem

Away from the lab, the commercial side of digital health keeps generating headlines without matching evidence. Recent coverage flagged in the dossier includes a Google Health and Weight Watchers partnership, a Vietnam distribution deal for a wearable ECG system from Huinno, and a smartwatch launch from Sekyo with an AI health sensor. None of those items is a study, and none is a substitute for one.

There is also a cultural problem inside research itself. A study published in Information, Communication and Society and reported by Nieman Journalism Lab on 28 September surveyed 1,138 communication scholars across 77 countries and held four focus groups. Nearly 70 per cent had already used generative AI in at least one research task, while most considered AI use inappropriate for most research tasks. The authors describe the resulting tension as a transparency paradox and call the effect "AI shame."

That finding does not touch wearables directly, but it describes the same fault line: tools arrive faster than the guidelines for judging them. The cancer study took years of epidemiological groundwork to produce a number policymakers can act on. The wearable papers arrive weekly and mostly measure healthy volunteers for a few hours. Both are useful. Only one is ready to shape a health system.