byUniversity of Manitoba

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Tobacco smoking is associated with an increased risk of hypertension (high blood pressure), a new UM study has found, and testing patients' urine can help to verify their smoking status and assess this risk.

The study was led by Dr. Setor Kunutsor, a cardiovascular epidemiologist who is professor of internal medicine and holds the Evelyn Wyrzykowski Research Chair in Cardiology in UM's Max Rady College of Medicine.

The findings were recentlypublishedin theJournal of Human Hypertension.

It's well known that smoking is associated with an increased risk of cardiovascular disease, but the relationship between smoking and hypertension has long been debated, with studies producing conflicting findings, the researchers said.

Most of the evidence on smoking and hypertension risk has been derived from studies that rely solely on people's self-reportedsmoking status. Few studies have used aurine testthat detects cotinine, a chemical substance that is a reliable biomarker for tobacco exposure.

The researchers studied data from about 3,300 adults who were part of a cohort study in the Netherlands. The study participants, whose mean age was 49, had no history ofhigh blood pressure.

Their smoking status (never smoked, formerly smoked, light current smoker or heavy current smoker) was assessed in two ways: through self-reporting and through testing of their urine for cotinine.

Associations of smoking exposures with new onset hypertension by sex. Credit:Journal of Human Hypertension(2025). DOI: 10.1038/s41371-025-01073-x

During a mean follow-up period of seven years, more than 800 participants developed hypertension. Thedata analysisshowed that both light and heavy current smoking, as measured by both self-reports and urine cotinine, were associated with an increased risk ofhypertension.

Kunutsor's team found that self-reporting of smoking status may underestimate the true association between smoking and high blood pressure because some patients under-report their smoking.

Routine urine testing for cotinine could help doctors to get a clear, objective picture of smoking status, and to detect the effects of inhaling secondhand (passive) smoke, the researchers said.

However, the current limitations of cotinine testing include the fact that in the UM study, more than half of the individuals classified as "never smokers" by urine testing actually described themselves as former smokers.

Since former smokers continue to face elevated cardiometabolic risk compared with never smokers, it's important to combine cotinine testing with detailed discussion with the patient about their smoking history, the research team said.

Emerging technologies, such as wearable biosensors, hold promise for continuous long-term monitoring of tobacco exposure, the researchers said. Such advancements could improve both research findings and cardiovascular risk management of patients.

More information: Setor K. Kunutsor et al, Self-reported smoking, urine cotinine, and risk of incident hypertension: findings from the PREVEND prospective cohort study, Journal of Human Hypertension (2025). DOI: 10.1038/s41371-025-01073-x

Provided by University of Manitoba