Health literacy and risk behaviours related to sexually transmitted infections among Portuguese university students: a cross-sectional study

Sexually transmitted infections (STIs) represent a growing concern for public health worldwide, particularly following the COVID-19 pandemic. Adolescents and young adults are disproportionately affected. Factual knowledge and personal beliefs seem to play a role in preventing sexual risk behaviours. Furthermore, adequate health literacy has been shown to improve health outcomes. Understanding the determinants of safer sexual practices is essential for developing more effective sexual health education interventions. Accordingly, this study aims to assess knowledge, attitudes, and practices towards STIs and health literacy levels in Portuguese young adults. A cross-sectional study was conducted among students at the University of Porto from September 2024 to January 2025. An online, structured, and anonymised questionnaire focused on STI aetiology, modes of transmission, clinical aspects, sexual risk behaviours, preventive practices, sociodemographic characteristics, and health literacy. Data were analysed using both descriptive and inferential methods. Lastly, the Mann-Whitney U test, Kruskal-Wallis H test, and multiple linear regression were used. Among 790 participants (median age 22.0 years), 84.0% had already initiated their sexual activity. Around half (49.7%) had problematic health literacy levels. HIV infection, genital herpes, and hepatitis B were the most widely known infections. Meanwhile, 50.9% were unaware of trichomoniasis, and 65.8% did not recognise parasites as potential etiological agents for STIs. Half of them expressed concern about contracting an STI, and similar proportions had used condoms at their last sexual intercourse (47.7%) and had been tested for HIV (51.5%). Regression models revealed that work experience in healthcare and better health literacy predict higher knowledge of STIs. In turn, knowledge was the strongest predictor of better attitudes. Moreover, being female, currently in a relationship, and having had a sexual debut at an older age were associated with safer sexual practices. This study identifies relevant knowledge gaps, determinants of sexual risk behaviours, and insufficient health literacy levels in Portuguese university students. These findings reinforce the need for accessible, proactive sexual health education interventions capable of empowering individuals and that are tailored to the values and beliefs of today’s youth.