Enhancing iodine health awareness among adolescents: a study protocol for a multi-country intervention study in educational settings across the UK, Slovenia, Cyprus, Bangladesh, Germany and Pakistan

Mild-to-moderate iodine deficiency remains a public health challenge, particularly in Europe and in areas where access to iodine-rich foods or iodised salt is limited. Adolescents are a key target group for interventions, as early awareness can reduce the risk of iodine deficiency during future pregnancies. The EUthyroid2 project aims to raise iodine awareness among adolescents (aged 13–17y) to improve their iodine awareness and possibly iodine intake and indirectly enhance the health of them and their future children. A multi-country intervention study will be conducted in educational settings across six countries (Bangladesh, Pakistan, Slovenia, Cyprus, Germany and the UK). Data on iodine awareness, dietary habits, and socioeconomic status will be collected at baseline (T1), 2–4 weeks post-intervention (T2), and 26–34 weeks post-intervention (T3). A convergent parallel mixed-methods design will be employed for process evaluation. The intervention includes three components: teaching modules, an iodine feedback tool, and an online learning platform. The core content includes an iodine feedback tool and a lecture on iodine-related knowledge and awareness, accompanied by student exercises. A total of 4,500 students will be recruited. The main outcome of the study is the change in participants’ awareness and knowledge of iodine from baseline (T1) to follow-up points (T2 and T3). The intervention is expected to effectively improved understanding of iodine’s importance for health and promoted positive behavioural intentions related to iodine intake, while also providing an opportunity to enhance iodine nutrition beyond the scope of the current trial. This study contributes to evidence on effective health promotion approaches aimed at addressing iodine deficiency. Expanding such awareness interventions could lead to lasting improvements in public health by reducing the prevalence of iodine deficiency disorders, particularly among adolescents and future generations. ClinicalTrials.gov number NCT06769009. Registered 2025-01-08.