Blood Pressure and Salivary Cotinine Levels in Young Adults Using Heated Tobacco Products: A Case–Control Study in Poland

<b>Background/Objectives</b>: Heated tobacco products (HTPs) are a gateway to nicotine addiction for non-smokers, especially young people. The short- and long-term health effects of using heated tobacco products are not yet fully understood. The study aimed to assess the effect of heated tobacco use on blood pressure and heart rate in young, healthy individuals aged 18-30. The study also assessed exposure to tobacco smoke by measuring salivary cotinine concentration. <b>Methods</b>: The case-control study was conducted in 2022-2025 among 200 healthy individuals aged 18-30 years: 70 I-Quit-Ordinary-Smoking users (IQOS), 65 daily traditional cigarette smokers (DS), and 65 non-smokers (NS). The research tool was a questionnaire containing information on the use of tobacco products. The participants completed a questionnaire and then underwent blood pressure measurements, anthropometric measurements, and saliva collection for cotinine levels. <b>Results</b>: The average age of initiation of IQOS use was 18.5 years, and smoking had continued for an average of 2.3 years. The average age of initiation of smoking traditional cigarettes was 16.3 years, and smoking had continued for 4.4 years. There were no statistically significant differences in median values between systolic blood pressure (SBP) and diastolic blood pressure (DBP) between the IQOS, DS, and NS groups (<i>p</i> > 0.05). High SBP values ≥ 140 mm Hg were observed in 10% of the IQOS users, 18.5% of the daily smokers of conventional cigarettes, and 12.3% of the non-smokers. High DBP values ≥ 90 mm Hg were observed in 11.4% of IQOS, 7.7% of DS, and 7.7% of NS. The cigarette smokers demonstrated significantly higher median cotinine levels compared to the IQOS users and non-smokers: 153.7 vs. 64.3 vs. 0.5 ng/mL (<i>p</i> < 0.01). Salivary cotinine levels were positively correlated (ρ = 0.38; <i>p</i> < 0.01) with the daily number of heated tobacco sticks among IQOS users (weak correlation), as well as among DS (ρ = 0.42; <i>p</i> < 0.01) with a higher daily number of cigarettes (moderate correlation). <b>Conclusions</b>: Long-term studies are needed to determine the health effects of heated tobacco products among young people in Poland. Furthermore, the potential impact of HTP aerosols on passive smokers should be examined. Further studies should consider the use of salivary cotinine as a biomarker.