Adaptation, Update and Validation of the General Nutrition Questionnaire in a Portuguese Adolescent Sample.

This article describes the adaptation of the adult Portuguese version of the General Nutrition Knowledge Questionnaire (GNKQ) for adolescents, and its validation. Respondents were 1,315 adolescents, who completed the questionnaire in two phases. A subsample of 73 adolescents was used to measure test-retest reliability. Concurrent validity was tested using a sample of 32 dietetic students. The adapted version showed high internal consistency (Cronbach's alpha = 0.92), test-retest reliability (R = 0.71) and concurrent validity (U = 22766.0; p < .01). Adolescents' nutrition knowledge can now be assessed with a valid and reliable instrument. Future validation works of this or others questionnaires for children and elderly are warranted.