Objective: The aim of the present work was to determine what dietary assessment method can provide a valid and accurate estimate of nutrient intake by comparison with the gold standard. Design: A MEDLINE, EMBASE, ISI Web of Science, Cochrane and related references literature review was conducted on dietary assessment methods for adolescents reporting the validity and/or reproducibility values. A study quality assessment on the retrieved FFQ was carried out according to two different scoring systems, judging respectively the quality of FFQ nutrition information and of FFQ validation and calibration. Setting: The present review considered adolescents attending high schools and recruited in hospitals or at home. Subjects: The target of the review was the healthy adolescent population in the age range 13-17 years. Results: Thirty-two eligible papers were included and analysed separately as 'original articles' (n 20) and 'reviews' (n 12). The majority (n 17) assessed the validation and reproducibility of FFQ. Almost all studies found the questionnaires to be valid and reproducible (r . 0?4), except for some food groups and nutrients. Different design and validation issues were highlighted, such as portion-size estimation, number of food items and statistics used. Conclusions: The present review offers new insights in relation to the characteristics of assessment methods for dietary intake in adolescents. Further meta-analysis is required although the current review provides important indications on the development of a new FFQ, addressing the need for a valid, reproducible, userfriendly, cost-effective method of accurately assessing nutrient intakes in adolescents.
Keywords
Dietary assessment Adolescents Validation ReproducibilityAdolescence is a critical period that is characterized by cognitive, emotional and social development and exposure to a significant turnover in lifestyle, including food intake and diet habits. Irregular meals, snacking and meal skipping, which characterize teenagers, often do not allow an accurate dietary assessment (1) and therefore the need to develop valid and reproducible instruments for this purpose is increasing. Different dietary assessment methods among adolescents have been extensively described and validated, such as food records (FR), FFQ, diet histories (DH) and 24 h recalls (24-HR). The FR is not used in large population studies for several reasons (2) : it can be quite expensive; it requires the participant to be literate and motivated; it involves trained staff; and it needs a computerized program specific to recording diet records. Thus, the FR is preferably used at the individual level and is generally considered a good reference instrument against which to validate other dietary methods to be used at the large population level, together with biomarker measurements (3) . The most used dietary assessment methods for large-scale surveys are therefore FFQ, 24-HR and DH, which present advantages such as cost-effectiveness, although they are affected by weaknesses (4,5) ...