Development and validation of a nutrition knowledge questionnaire for a Canadian population

Objective: The present study aimed to develop and validate a nutrition knowledge questionnaire in a sample of French Canadians from the province of Quebec, taking into account dietary guidelines. Design: A thirty-eight-item questionnaire was developed by the research team and evaluated for content validity by an expert panel, and then administered to respondents. Face validity and construct validity were measured in a pre-test. Exploratory factor analysis and covariance structure analysis were performed to verify the structure of the questionnaire and identify problematic items. Internal consistency and test-retest reliability were evaluated through a validation study. Setting: Online survey. Subjects: Six nutrition and psychology experts, fifteen registered dietitians (RD) and 180 lay people participated. Results: Content validity evaluation resulted in the removal of two items and reformulation of one item. Following face validity, one item was reformulated. Construct validity was found to be adequate, with higher scores for RD v. non-RD (21.5 (SD 2.1) v. 15.7 (SD 3.0) out of 24, P< 0.001). Exploratory factor analysis revealed that the questionnaire contained only one factor. Covariance structure analysis led to removal of sixteen items. Internal consistency for the overall questionnaire was adequate (Cronbach's alpha = 0.73). Assessment of test-retest reliability resulted in significant associations for the total knowledge score (r = 0.59, P < 0.001). Conclusions: This nutrition knowledge questionnaire was found to be a suitable instrument which can be used to measure levels of nutrition knowledge in a Canadian population. It could also serve as a model for the development of similar instruments in other populations.