title: Evaluating the quality of dietary intake validation studies.
abstract: Within the EURopean micronutrient RECommendations Aligned Network of Excellence (EURRECA), a scoring system was developed to assess the quality of dietary intake validation studies. The scoring system included three steps. The first step was to give each study a quality score, which included five components: sample size, statistics used, data collection procedure, consideration of seasonality and supplement use. Scores ranged from 0 to 7, and validation studies classified as very good ( > or = 5), good (5-3.5), acceptable/reasonable (3.5-2.5) and poor ( < 2.5). The second and third steps included an adjustment/weighting of the correlation coefficient according to the quality score and moreover a rating of the adjusted/weighted correlation. The scoring system was tested in 124 validation studies that included at least one vitamin. Only 5.6 % of the 124 studies were judged to be of very good quality according to the quality score, 41.9 % of good quality and 16.9 % had a poor rating. When adjusting for the study quality scores, crude and adjusted mean correlations of vitamins A, C, D and E intakes were similar, but the percentage of correlation values classified as poor or very good was higher after adjustment. These results show the importance of considering the quality of studies validating dietary assessment methods and the correlations obtained for the micronutrient of interest when interpreting effects observed in epidemiological studies using dietary assessment methods. Without a doubt, this subject constitutes a key topic for research in nutritional epidemiology.
authors.affiliation: Nutrition Research Group, Department of Clinical Sciences, Centre for Health Sciences, University of Las Palmas de Gran Canaria, 35080 Las Palmas de Gran Canaria, Spain. lserra@dcc.ulpgc.es
authors.forename: Lluis
authors.initials: L
authors.lastname: Serra-Majem
authors.forename: Lene
authors.initials: L
authors.lastname: Frost Andersen
authors.forename: Patricia
authors.initials: P
authors.lastname: Henríque-Sánchez
authors.forename: Jorge
authors.initials: J
authors.lastname: Doreste-Alonso
authors.forename: Almudena
authors.initials: A
authors.lastname: Sánchez-Villegas
authors.forename: Adriana
authors.initials: A
authors.lastname: Ortiz-Andrelluchi
authors.forename: Eva
authors.initials: E
authors.lastname: Negri
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D004032:Diet; D004034:Diet Surveys; D004812:Epidemiologic Methods; D005060:Europe; D005069:Evaluation Studies as Topic; D006801:Humans; D018977:Micronutrients / Q000008:administration & dosage*; D015596:Nutrition Assessment; D052756:Nutritional Sciences / Q000592:standards*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires
chemical_list: D018977:Micronutrients