Development and reproducibility of a brief food frequency questionnaire for assessing the fat, fiber, and fruit and vegetable intakes of rural adolescents

Objective To describe the systematic development and reproducibility of a f ood frequency questionnaire (FFQ) designed to meet the specific research re quirements of the Goals for Health cancer prevention intervention program f or rural middle school children. Design A 4-step process was used to develop a brief FFQ for scoring intakes of total fat, fiber, and fruits and vegetables. The resulting questionnair e consisted of 25 food frequency items and 10 supplemental questions. Repro ducibility of the questionnaire was determined by comparing. responses at t he beginning and end of a 4-month interval. Subjects Study subjects were sixth- and seventh-grade students attending mi ddle schools in rural areas of Virginia and upstate New York. Seventh-grade students participated in the pilot study, and sixth-grade students partici pated in the reproducibility study. The final version of the FFQ was comple ted twice by 539 sixth graders. After exclusions for missing and unreliable data, the usable sample size was 415. Boys were somewhat more likely than girls to be excluded for missing data. African-American students comprised 32% of the population. Statistical analyses performed Each food frequency item was associated with 3 scores-a fat score, a fiber score, and a combined score for the number o f servings of fruits and vegetables. Means and standard deviations were det ermined for nutrient variables, differences between repeat administrations; were tested for significance by paired t test, and Pearson correlation coe fficients were calculated for nutrients and for individual food items. Results Correlation coefficients for nutrient scores were, 0.58 for fat, 0. 49 for fiber, and 0.51 for fruits and vegetables. For individual food items , correlations ranged from 0.24 to 0.59 (mean = 0.41). Applications/conclusions Using a systematic approach to developing a study- specific FFQ for rural adolescents is feasible. Further, the reproducibilit y of the Goals for Health questionnaire was demonstrated for the 3 nutrient scores it, was designed to measure. This developmental approach may be rea dily adapted to other populations, study designs, and nutrients of interest . The validity of the questionnaire remains to be tested.