What were the top medical developments in 2025? Medscape News Canada reviewed the five most-read Canadian stories of the year, which generated significant interest and, in some cases, controversy. Here’s the countdown!

5. Canadian Cardiologists Must Step Up Care for Long COVID

This story reminds readers that long COVID is still very much a condition that needs and deserves to be treated, particularly by cardiologists. Based on presentations in an educational session at the Canadian Cardiovascular Congress (CCC) 2025, the story highlights the cardiovascular impacts of the condition, diagnostic difficulties, and treatment options.

A presenter shared data showing an increased risk for major cardiovascular events and acute myocardial infarction following SARS-CoV-2 infection and a fivefold increased risk for myocarditis in the year following the index infection.

Another reported on long COVID-related myopericarditis, showing in her team’s study that more than a third of participants with a post-COVID condition had MRI-confirmed cardiac involvement. Because wait times for cardiac MRI, a definitive test for myopericarditis, can be months or years, the presenter recommended treating when there is a high clinical suspicion, with colchicine as the first-line choice and anakinra as a second-line option. Importantly, clinicians should not take a wait-and-see approach because patients don’t recover spontaneously, even after several years, according to the presenter.

Vaccine-associated myocarditis was also discussed. Although rare, it may have an incidence as high as 39 per 100,000 doses among adolescent and young adult males, according to the presenter. The condition typically is diagnosed when young men arrive at the emergency department with chest pain and a cardiac MRI shows fibrosis or a reduced ejection fraction. Treatment involves nonsteroidal anti-inflammatory drugs or cardiac medications, although the condition often resolves on its own within 3-6 months.

This story was popular with readers and drew no comments.

4. 2 New Studies Show Cardiovascular Disease (CVD) Benefit of Portfolio Diet

This story reports on two studies that suggest that the plant-based Portfolio Diet can lower cholesterol, thereby reducing the risk for CVD and all-cause mortality. The diet focuses on the following five food groups: nuts and seeds, plant protein (eg, beans or tofu), viscous fiber (eg, apples, oatmeal, and eggplant), plant sterols (eg, soybeans and peas), and monounsaturated fatty acids (eg, extra virgin olive oil).

For the first study, researchers analyzed data from 14,835 US adults in the National Health and Nutrition Examination Survey (1988-1994). Their diets were assessed at baseline by 24-hour recall and a food frequency questionnaire using the Portfolio Diet Score (PDS). Positive points were assigned for foods included in the diet; negative points were assigned for foods high in saturated fat and cholesterol.

An 8-point increase in PDS was associated with a 12% lower risk for CVD mortality at 22 years’ follow-up. Higher adherence to the diet was also associated with lower risks related to blood lipids, glycemia, and inflammation.

The second observational study focused on outcomes of the diet in 1507 ethnoculturally diverse people in their twenties. Adherence was measured using the PDS, and the data were adjusted for potential confounders.

An 8-point higher PDS was associated with 3% lower low-density lipoprotein cholesterol, the primary outcome. Researchers also found that 50% adherence to the diet beginning in young adulthood might delay increases in CVD risk later in life by about 6 years, whereas strict adherence could delay CVD risk by up to 13 years.

Most readers responded favorably to the story, but one commentator, J. Sigel, was concerned about possible selection bias. He noted that participants who adhered to the Portfolio Diet might also be following a lifestyle associated with better health outcomes. He wondered whether the studies “measure the effects of this diet or the effects of lifestyle.” He also questioned whether the Portfolio Diet is better than any other diet that is high in fruits, vegetables, and other healthful foods.

3. Online Program Helps Women Improve Sexual Dysfunction

This story reports on a study of the eSense online program for the treatment of sexual interest/arousal disorder (SIAD) in women. The program led to significant improvement in symptoms such as low sexual desire and sexual distress, and the improvements were maintained for 6 months.

eSense offers both cognitive-behavioral therapy (CBT) and mindfulness-based therapy (MBT). For the study, 43 women with SIAD were randomly assigned to the eSense CBT program and 43 to the MBT program. The two groups were compared with 43 women on a waitlist. Both eSense programs included eight modules over 12 weeks and up to 12 remote meetings with nonexpert “navigators” who were trained to provide empathic listening, encouragement, and technology support, but not formal therapy.

Compared with the waitlist controls, both eSense treatment groups reported statistically significant improvements in the primary outcomes at post-treatment, with desire/arousal scores improving by 10-12 points and distress scores decreasing by 7-11 points on average.

Among the secondary outcomes, sexual satisfaction scores increased by about 10 points in the CBT group and 11 points in the MBT therapy group. Overall sexual function also improved by about 6 points in both groups.

An independent commentator in the story noted, “A unique aspect of eSense is that it is not delivered by an expert, which may increase its accessibility and affordability, particularly because it could reduce barriers related to stigma or embarrassment in seeking treatment.”

One reader, Jennifer Manson, said she was “a little stunned that this is discussed as if the problem and the fix is for women to address, when often the problem is an insufficiently attentive and caring partner willing to put in the effort to please the other person, instead of just themselves.”

Evelyn Doe responded that “plenty of women have attentive partners and still struggle with physical and psychological barriers to a fulfilling sex life.”

2. Acetaminophen and Autism: What Do the Data Say?

This commentary by Stephen A. Hoption Cann, PhD, clinical professor and epidemiologist in the School of Population and Public Health at the University of British Columbia in Vancouver, addresses an important public health controversy: the connection between acetaminophen and autism. Hoption Cann traces the history of research into potential associations between acetaminophen exposure and adverse neurodevelopmental disorders (NDDs), including autism, highlighting that association cannot show causation.

Hoption Cann chronicles the “dramatic rise” in acetaminophen’s popularity after studies in the 1980s linked aspirin use in children to Reye syndrome. But around the same time that acetaminophen replaced aspirin in pregnant women, autism rates began to rise, although brief declines in use followed Tylenol tampering incidents in the 1980s.

The prevalence of autism was estimated at 4 in 10,000 in 1970, but by 2022, it was roughly 1 in 31. While various factors might explain the rise, “many experts believe the growing case numbers reflect a genuine increase in prevalence” of autism and other NDDs, Hoption Cann wrote, although the connection remains controversial.

“For better or worse, a real-world experiment is now underway,” he wrote. Many women contemplating pregnancy are now aware of the debate, and “this heightened awareness is likely to lead to a decline in acetaminophen use during pregnancy. Whether this shift will result in a corresponding change in the incidence of NDDs remains to be seen.”

He advises clinicians to be transparent with patients about the lack of a definitive conclusion about the connection, noting “It would be premature to offer blanket reassurance about the safety of this drug during pregnancy….Presenting the available information honestly allows patients to make informed choices, even in the face of incomplete data.”

This story was popular with readers and drew no comments.

1. Do Tattoos Pose a Cancer Risk?

Tattoos are gaining in popularity, and patients increasingly ask their providers about potential health risks, Hoption Cann wrote this engaging commentary, in which he responds to concerns about tattooing, particularly cancer risks, in Canada and globally.

The “hundreds of brands” and “thousands” of ink colors on the market are just two of the factors that make it difficult to explore whether tattooing might lead to cancer. Tattoo size and the number of tattoos an individual has may also play a role in determining risk, he wrote. Confounding factors such as smoking, drinking alcohol, socioeconomic status, and other demographics also “must be accounted for.”

Canada and the EU have lists of substances in tattoo inks that might be carcinogenic or mutagenic, but the FDA takes a laissez-faire approach. Hoption Cann summarized key studies investigating links between tattoo pigments and lymphoma, skin cancer, and a few hematologic cancers, but overall, he wrote, “many uncertainties” remain.

Large cohort studies are underway, but it could take 10-20 years to get more definitive answers. For now, he advised, clinicians can tell patients about the potential risks, as well as the difficulties in removing tattoos once they’re applied. “It would be premature to assure patients that tattoos are entirely risk-free,” he concluded.

Several readers expressed frustration with the lack of evidence in this area and the need for more definitive studies. Pathologist Nancy Ulanowicz wrote that she “find[s] it annoying to have to read around the pigment deposition in lymph nodes from an axillary or inguinal node dissection.”

Sara A. commented, “Tattoo artists have most of their bodies covered, and I have never heard of a higher incidence of cancer among them. I’m sure that would be widely talked about if this was the case.”

Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDEdge, The Lancet (where she was a contributing editor), and Reuters Health.