Objective: Initiatives promoting the reduction of high-salt food consumption by consumers need to be partly based on current levels of salt knowledge in the population. However, to date there is no validated salt knowledge questionnaire that could be used to assess population knowledge about dietary salt (i.e. salt knowledge). Therefore, the aim of the present study was to develop and validate a salt knowledge questionnaire.
Design: A cross-sectional study was conducted on an online web survey platform using convenience, snowball sampling. The survey questionnaire was evaluated for content and face validity before being administered to the respondents.
Setting: Online survey.
Subjects: A total of forty-one nutrition experts, thirty-two nutrition students and thirty-six lay people participated in the study.
Results: Item analyses were performed to evaluate the psychometric properties of the test items. Twenty-five items were retained to form the final set of questions. The total scores of the experts were higher than those of the students and lay people (P < 0·05). The total salt knowledge score showed significant correlations with use of salt at the table (ρ = -0·197, P < 0·05) and inspection of the salt content in food products when shopping (ρ = 0·400; P < 0·01).
Conclusions: The questionnaire demonstrated sufficient evidence of construct validity and internal consistencies between the items. It is likely to be a useful tool for the evaluation and measurement of levels of salt knowledge in the general population.