[Development and validation of a nutritional knowledge questionnaire among 9- to 15-year-olds].

Improving nutritional knowledge is a frequent goal in nutritional education programs. However, there is a lack of valid instruments to assess nutritional knowledge in children. Questionnaires on nutritional knowledge are usually related to a specific curriculum or program, and their development or validation process is rarely available. Our goal was to develop a valid, self-administered questionnaire to assess nutritional knowledge among French-speaking children and adolescents aged 9-15 years. The conceptual framework and concepts were based on a literature review. For each concept, an expert panel selected a number of items, and successive versions of the questionnaire were pretested. The edited version of a 30-item questionnaire (QuesCA) was administered to 475 children aged 9-15, in two French-speaking cantons in Switzerland. We calculated internal consistency (Cronbach alpha), the rate of correct answers for each question, and the mean scores for each concept. The mean scores were 16.32 (95% CI: [15.69; 16.94]) in the 9- to11-year-olds and 18.62 [18.19; 19.06] in the 12- to 15-year-olds (maximum possible, 30). Beverages, breakfast, fruit, and vegetables were the concepts that gathered the most correct answers. The overall Cronbach alpha score was good (0.66), but as the internal consistency for each concept was low (0.06-0.45), we developed an optimal scale for each age group. The result is a two-part questionnaire: QuesCA 9-11 and QuesCA 12-15, with 9 items each, that enables a rapid and reliable assessment of nutritional knowledge in children and adolescents.