Education and Literacy for an Active Life (Educação e Literacia Para Uma Vida Ativa)

Overall health literacy score, assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C), specifically developed for this study and adapted to the Portuguese educational and sociocultural context. This instrument is under validation and was designed to evaluate health literacy competences in children aged 9-12 years, encompassing four core health literacy dimensions: access, comprehension, evaluation and application, of health-related information. The instrument covers five critical domains of health promotion relevant to this age group: diet, PA, sedentary behaviour, sleep and mental health and includes a total of 47 items, scored 0-20 points/item, on a total of 0-100 points). The higher the score, the higher the Literacy level. Item development was based on an extensive review of validated instruments and international guidelines.

Health Literacy on Nutrition will be assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C). Items on Nutrition (1-20/47) reflect core principles of food literacy and public health nutrition, including nutrient awareness, label reading, and balanced eating habits. Along with categorical analysis, numerical analysis will be also performed (score 0-20). The higher the score, the higher the Literacy level.

Health Literacy on Physical Activity will be assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C). Items on Physical Activity (21-30/47) include an adaptation from the Physical Activity Questionnaire for Adolescents - PAQ-A (Kowalski et al., 2004) focusing on knowledge, perceived benefits, obstacles, and engagement in activity. Along with categorical analysis, numerical analysis will be also performed (score 0-20). The higher the score, the higher the Literacy level.

Health Literacy on Sedentary Behaviour will be assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C). Items on Sedentary Behaviour (31-33/47) draws from the Adolescent Sedentary Activity Questionnaire - ASAQ (Hardy et al., 2007), adapted to assess screen time and perceived health impacts. Along with categorical analysis, numerical analysis will be also performed (score 0-20). The higher the score, the higher the Literacy level.

Health Literacy on Sleep will be assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C). Items on Sleep (34-41/47) were specifically developed for this study, informed by international public health guidelines on sleep hygiene in childhood (Paruthi et al., 2016). These items explore the children's understanding of sleep routines, behaviours, caffeine use, and reliable sources of information on sleep. Although thematically related to constructs evaluated in clinical tools such as the Pittsburgh Sleep Quality Index (Pittsburgh Sleep Quality Index - PSQI (Buysse et al., 1989), the purpose of these items is educational, aligned with health literacy competences, and adapted to children's cognitive levels. Along with categorical analysis, numerical analysis will be also performed (score 0-20). The higher the score, the higher the Literacy level.

Health Literacy on Mental health will be assessed by the Questionnaire on Literacy in Health Behaviours for Children (QLCS-C). Items on Mental Health (42-47/47) focus on emotional literacy, stress regulation, and social support, with two items adapted from the Flourishing Scale (Diener et al., 2009). Along with categorical analysis, numerical analysis will be also performed (score 0-20). The higher the score, the higher the Literacy level.