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

Abstract 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.