Evaluation of Mediterranean diet adherence scores: a systematic review

OBJECTIVE The aim of this review was to evaluate the conceptual suitability, applicability and psychometric properties of scores used internationally to measure adherence to the Mediterranean diet (MD). DESIGN This was a systematic review to identify original articles that examined some aspects of the conceptual suitability, applicability or psychometric properties of the MD adherence score. Electronic searches were carried out on the international databases MEDLINE, Scopus, Web of Science and EMBASE (from January 1980 to 31 December 2015). ELIGIBILITY CRITERIA FOR SELECTING STUDIES The study included original articles that examined some aspects of the conceptual suitability, applicability or psychometric properties of the MD adherence score. The studies where MD adherence scores were administered but did not bring forward any evidence about their performance related to conceptual suitability, applicability or psychometric properties were excluded. DATA EXTRACTION Information relating to the scales was extracted in accordance with the quality criteria defined by the Scientific Advisory Committee of the Medical Outcomes Trust for measurement of health results and the quality criteria recommended by Terwee: (1) conceptual, (2) applicability and (3) psychometric properties. Three authors independently extracted information from eligible studies. RESULTS Twenty-seven studies were identified as meeting the inclusion criteria, yielding 28 MD adherence scores. The results showed that evidence is scarce and that very few scores fulfilled the applicability parameters and psychometric quality. The scores developed by Panagiotakos et al, Buckland et al and Sotos-Prieto et al showed the highest levels of evidence. CONCLUSIONS Scores measuring adherence to MD are useful tools for identifying the dietary patterns of a given population. However, further information is required regarding existing scores. In addition, new instruments with greater conceptual and methodological rigour should be developed and evaluated for their psychometric properties.