Development and validation testing of a weight management nutrition knowledge questionnaire for Chinese adults (C-WMNKQ).

Objective: To develop a weight management nutrition knowledge questionnaire for Chinese adults (C-WMNKQ) and to test its reliability and validity.

Methods: We evaluated the content validity of the questionnaire using the expert consultation method, evaluated the face validity of the questionnaire through a pre-survey, eliminated the questions that did not meet the criteria through item difficulty, item differentiation, and inter-item correlation. We verified the construct validity using the known-groups comparison method. Correlation analysis by comparing it with the general nutrition knowledge questionnaire for Chinese adults (C-GNKQ) was conducted for criterion validity evaluation. The internal consistency reliability, split-half reliability, and test-retest reliability validation were also evaluated, and relevant evidence of expected convergent validity was obtained.

Results: The final C-WMNKQ contains 39 items in 5 dimensions. The overall internal consistency of the C-WMNKQ was 0.808 for Cronbach's alpha coefficient, 0.81 for ω coefficient, 0.788 for Guttman's coefficient, 0.843 for Spearman's correlation coefficient, and 0.908 for overall ICC (95% CI = 0.870-0.935). Meeting the criterion of structural validity, nutrition professionals scored 26.3% higher than those in the financial field, p < 0.001. The correlation coefficient between the total C-WMNKQ score and the total C-GNKQ score was 0.641, p < 0.001, which is good for criterion validity. In terms of convergent validity, the level of nutrition knowledge of women was higher than that of men, the partial nutrition knowledge score of participants aged 35-54 years old was significantly higher than that of participants aged 18-34 years old, the level of nutrition knowledge of those with higher education was higher. Participants with per capita monthly household income >8000RMB had significantly higher partial nutrition knowledge scores than those with <3000RMB and 3000-5000RMB.

Conclusions: C-WMNKQ has good reliability and validity and can be used as a valid tool to assess the nutrition knowledge of Chinese adults related to weight management.