title: Comparative validity of the ASSO-Food Frequency Questionnaire for the web-based assessment of food and nutrients intake in adolescents.
abstract: BACKGROUND
  A new web-based food frequency questionnaire (the ASSO-FFQ) was developed within the ASSO Project funded by the Italian Ministry of Health.
  
  
  OBJECTIVE
  The aim of the present study is to assess the validity of the ASSO-FFQ at food groups, energy, and nutrients level.
  
  
  METHODS
  The validation study compared the ASSO-FFQ against a weighted food record (WFR) measuring foods, beverages and supplements intake, compiled during the week following the ASSO-FFQ administration. Ninety-two subjects aged 14-17, recruited from secondary schools in Palermo (Italy), completed the ASSO-FFQ and WFR. The intake of 24 food groups, energy, and 52 nutrients were taken as main outcomes. Tests for paired observations, Spearman and Pearson's correlation coefficients (cc), kappa statistics and classification in quintiles, Bland-Altman plots and multiple regressions, on untransformed and transformed data were used for the statistical analysis.
  
  
  RESULTS
  High cc (≥0.40) were found for soft drinks, milk, tea/coffee, vegetables, and lactose; fair energy-adjusted cc (0.25-0.40) for water, alcoholic drinks, breakfast cereals, fishery products, savory food, fruit juice, eggs, and 19 nutrients. The subjects classified in the same or adjacent quintile for food groups ranged from 40% (alcoholic drinks) to 100% (dried fruit); for energy and nutrients from 43% (phosphorus, thiamin, niacin) to 77% (lactose). Mean differences were not significant for water, soft drinks, meat, sweets, animal fats, milk and white bread, and vitamin B12 and folate. Limits of Agreement were broad for all food groups and nutrients. School, gender, alcohol consumption and between meals mainly affected most food groups' intake differences. Gender stratification showed females had increased Pearson's cc for energy and 28 nutrients, such as almost all fats, carbohydrates, vitamins and minerals.
  
  
  CONCLUSIONS
  The ASSO-FFQ could be applied in epidemiological studies for the assessment of dietary consumption in adolescents to adequately rank food, energy and nutrient intakes at a group level.
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy; tabacchi.garden@libero.it.
authors.forename: Garden
authors.initials: G
authors.lastname: Tabacchi
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Filippi
authors.affiliation: Division of Non-communicable Diseases and Life-Course, World Health Organization Regional Office for Europe, Copenhagen, Denmark.
authors.forename: João
authors.initials: J
authors.lastname: Breda
authors.affiliation: Agricultural Research Council, Food and Nutrition Research Centre (CRA-NUT), Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Censi
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Amodio
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Napoli
authors.affiliation: Sport and Exercise Sciences Unit, University of Palermo, Palermo, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Bianco
authors.affiliation: Centre for Sport and Human Performance, University of Greenwich, London, UK.
authors.forename: Monèm
authors.initials: M
authors.lastname: Jemni
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Firenze
authors.affiliation: Department of Sciences for Health Promotion and Mother Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Mammina
keywords: adolescent; food frequency questionnaire; intake; nutrient; validation; validity