Sammanfattning
Background: A new web-based food frequency questionnaire (the ASSOFFQ) 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 ASSOFFQ at food groups,
energy, and
nutrients level.
Design and subjects: The validation study compared the ASSOFFQ against a weighted food record
(WFR)
measuring foods, beverages and supplements intake, compiled during the week following the
ASSOFFQ
administration. Ninety-two subjects aged 1417, recruited from secondary schools in Palermo (Italy),
completed
the ASSOFFQ 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, BlandAltman 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
energyadjusted
cc (0.250.40) 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 ASSOFFQ 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.