Validity of two short screeners for diet quality in time-limited settings

Objective: An urgent need in dietary assessment is the development of short tools that provide valid assessments of dietary quality for use in time-limited settings. The present study assessed concurrent and construct validity of the short Diet Quality Screener (sDQS) and brief Mediterranean Diet Screener (bMDSC) questionnaires. Design: Relative validity was measured by comparing three dietary quality indices - the Diet Quality Index (DQI), the modified Mediterranean Diet Score (mMDS) and the Antioxidant Score (ANTOX-S) - derived from the two questionnaires with those from multiple 24 h recalls over 12 months. Construct validity was demonstrated by correlations between average nutrient intake recorded on multiple 24 h recalls and the DQI, mMDS and ANTOX-S derived by the short screeners. Setting: Both short questionnaires were administered to 102 participants recruited from a population-based survey in Spain. Results: DQI, mMDS and ANTOX-S correlated (P<0.001) with the corresponding 24 h recall indices (r=0.61, 0.40 and 0.45, respectively). Limits of agreement lay between 96 and 126 %, 59 and 144% and 61 and 118% for the DQI, ANTOX-S and mMDS, respectively. Dietary intakes of fibre, vitamin C, vitamin E, Mg and K reported on the 24 h recalls were positively associated (P<0.04) with the DQI, mMDS and ANTOX-S indices. Conclusions: The sDQS and bMDSC provide reasonable approximations to food-based dietary indices and accurately situate subjects within the indices constructed for the present validation study.