Psychometric Validation of a Brief Self-report Measure of Diet Quality: The DASH-Q

Objective: The Dietary Approaches to Stop Hypertension (DASH) diet is recommended for primary and secondary prevention of cardiovascular chronic diseases. This study describes the development, internal consistency, and validation (predictive and convergent) of a population-based, self-report measure (the DASH Quality [DASH-Q]) to assess adherence to the DASH diet among adults. Design: Cross-sectional online surveys to evaluate the psychometric properties of the DASH-Q. Participants: US adults consisting of a national sample (n = 407) and a Southern university sample (n = 405). Main Outcome Measures: Diet quality scores. Analysis: Item and scale psychometric properties were examined using corrected item total correlations and principal component analysis. The authors validated the DASH-Q by examining associations with an existing self-report nutrition scale and other nutrition-related behaviors. Results: The DASH-Q yielded acceptable internal consistency (alpha = .77 .83) in both samples. The DASH-Q scores correlated moderately to strongly with all nutrition-related criteria (P < .01), suggesting evidence of predictive and convergent validity. Less than 15% of either sample reported high diet quality. Conclusions and Implications: The DASH-Q had sufficient psychometric robustness for use as a population-based measure. The DASH-Q is recommended as an easily used measure of DASH adherence for populations that need to modify their diet to manage chronic illness.