The relative validity of a short Dutch questionnaire as a means to categorize adults and adolescents to total and saturated fat intake

Background To assess the relative validity of a short food frequency questionnaire, the Fat list, to be used in (the evaluation of) nutrition education programmes. Methods Forty-five adults and 50 adolescents (12-18 years old) completed the Fat list at home, and subsequently kept diet records for seven subsequent days. Results Pearson correlations of about 0.7 for adults and 0.6 for adolescents were observed between fat scores derived from the Fat list and total and saturated fat intake in grams estimated by the 7-day diet records. Correlations varied among subpopulations based on sex, age, education, household size and responsibility for cooking and shopping. Lower correlations were especially found for female adolescents and older adolescents (16-18 years old). Pearson correlations between the Fat list and percentages energy from fat were low for both adults and adolescents. Gross misclassification, defined as disagreement between the two fat consumption assessments beyond an adjacent tertile, was less than 6% for all but the female adolescents. Conclusions The Fat list can be used in adult and male adolescent populations to classify subjects in broad categories of total and saturated fat intake in grams and to assess differences in absolute and saturated fat intake between groups as a result of nutrition education programmes.