Background: High salt intake is considered as one of the most important causes of hypertension and cardiovascular diseases. Measuring and identifying factors contributing to people's salt intake behaviors is important to evaluate effectiveness of interventions focusing on salt reduction behaviors. The purpose of this study was to develop and test a new theory of planned behavior (TPB)- based instrument to measure factors influencing three different salt intake behaviors (adding salt during cooking, at the table, purchasing salty food) among women.
Study design: A mixed-method study.
Methods: After the face and content validity of developed instrument were established, a representative sample of women (N= 300, age (SD):42.82(12.10)) were recruited to assess the construct validity using Partial Least Square confirmatory factor analysis. Coefficient alpha and composite reliability (CR) were used to establish reliability of instrument. The content validity index (CVI) and content validity ratio (CVR) were used to assess the content validity.
Results: Assessing validity and reliability of instrument led to 56-item questionnaire. CVI was more than 0.70 and CVR more than 0.56. Internal consistency as assessed by Cronbach's alpha was acceptable. Convergent and discriminant validity were established. The GOF index for behavior one was 0.250, for behavior two was 0.414 and behavior three was 0.374. The results of confirmatory factor analysis indicate that TPB model has an acceptable fit with data.
Conclusion: Our instrument provides a validated and reliable tool for assessing different aspects of salt intake behaviors in women to evaluate effectiveness of interventions focusing on salt reduction behaviors.
Keywords: Eating behavior; Hypertension; Psychometric; Questionnaire; Women.