Reliability and validity of the Children's Dietary Questionnaire; a new tool to measure children's dietary patterns.

Objective: To assess the reliability and validity of a new parent report measure of children's dietary patterns, allowing assessment against national guidelines.
Methods: The 28-item Children's Dietary Questionnaire (CDQ) was developed based on Australian healthy eating guidelines and knowledge of current dietary intake of Australian children. It assesses intake patterns in either the previous week or 24 hours of foods for which intake is recommended (positive indicators - fruit, vegetables, water, reduced fat products) and foods for which intake is discouraged (negative indicators - high fat/sugar foods [non-core foods], sweetened beverages and full fat dairy products). Four food group subscales are generated: fruit and vegetable, fat from dairy, sweetened beverages and non-core foods. Test-retest reliability, internal consistency, relative validity and the ability to detect change were tested in five separate study samples of children, totalling 706 children aged 4 to 16 years.
Results: The fruit and vegetable and non-core foods subscales demonstrated good internal consistency (alpha 0.76 and 0.62, respectively) and item:total correlations greater than 0.2. The fat from dairy and the sweetened beverages subscales consistently performed poorly. All subscales demonstrated satisfactory test-retest reliability (intraclass correlation coefficient 0.51 to 0.90) and ability to detect change in the expected direction following a weight management intervention. Relative validity suggests ability to distinguish positive or negative dietary risk based on CDQ scores at the group but not individual level.
Conclusion: The CDQ shows acceptable reliability and relative validity for assessing group level child dietary patterns with key aspects of healthy eating guidelines.