Reliability and validity of a questionnaire measuring knowledge, attitude and practice regarding “oil, salt and sugar” among canteen staff

Excessive intake of oil, salt and sugar is closely associated with the prevalence of non-communicable chronic diseases (NCDs). Canteen staff’s knowledge, attitude and practice (KAP) about oil, salt and sugar directly affect the content in dishes and the consumers’ intake. However, no valid questionnaire is used to assess KAP among canteen staff about the “oil, salt and sugar”. Therefore, the present study aimed to establish and validate a questionnaire to evaluate the KAP of canteen staff about the “oil, salt and sugar”. This cross-sectional study was conducted among canteen staff randomly selected from three college canteens. Participants completed the questionnaire and retested it two weeks later. Internal and test–retest reliability were assessed using Cronbach’s α and Pearson correlation coefficients, respectively. Validity was assessed using the exploratory factor analysis. 100 participants finished the questionnaire, of which 66% were females with a mean age of 40.3 ± 10.5 years. The Cronbach’s α coefficients of the total questionnaire and Knowledge, Attitude and Practice dimensions were 0.822, 0.830, 0.752 and 0.700, respectively. The test–retest reliability coefficient was 0.968. In exploratory factor analysis, nine common factors were extracted, with 26 items, and the cumulative contribution rate was 70.9%. The questionnaire had a satisfactory property for measuring the KAP of the “oil, salt and sugar” among canteen staff in China.