Validity of a questionnaire to assess fruit and vegetable intake in adults

Abstract

Objective: To validate a method for assessing fruit and vegetable intake among adults in a population of low intake. The method assesses mean intake and ranks individuals by their usual intake. Design: A precoded fruit and vegetable Questionnaire included a 24-h recall and a food frequency. The participants filled in the Questionnaire, a week later they started a 7-day food record, 1-day weighed record and 6 days using household measures. Subjects: Following advertisements 40 participants were recruited, 36 returned food records(mean age ¼ 37 years). Results: No difference was observed between the average intake yielded by the 24-h recall and that from the 1-day weighed food record of fruits or vegetables. Correlation coefficients between results from the food frequency questionnaire and the 7-day food records were 0.45 (P ¼ 0.007) for vegetables, 0.63 (Po0.001) for fruits and 0.73 (Po0.001) for fruits and vegetables combined. Cross-classification into quartiles showed that the proportion of participants in the same or the adjacent quartile of the intake distribution were 94% for fruit intake and 80% for vegetable intake. Registered intake of fruits and vegetables was higher the first 4 days of the record than the last 3 days (P ¼ 0.002). The 4-day food record correlated with the food frequency questionnaire in similar manner as the 7-day record. Conclusion: The present study indicates that the precoded 24-h recall may be valuable tool for measuring average intake of fruits and vegetables among adults in a population of low intake. Moreover, the food frequency questionnaire was valid for ranking individuals according to their usual intake. A 4-day food record might be sufficient when validating food frequency questionnaires for fruits and vegetables.

Children’s and parents’ perceptions of the determinants of children’s fruit and vegetable intake in a low-intake population

“…This dietary assessment showed high reliability and validity. The results have been presented elsewhere (19,20) . An overview of the variables assessed, and the children's and parents' questions on determinants of fruit and vegetable consumption, is presented in Table 1.…”

A systematic review of methods to assess intake of fruits and vegetables among healthy European adults and children: a DEDIPAC (DEterminants of DIet and Physical Activity) study

“…However, the instrument had good agreement with 24-HDR in a sample of Spanish children (135) and has been demonstrated to be reproducible (145) . The Pro-Children instrument, when compared with 7 d (130) and 1 d (42) diet records, was reported to have moderate to good validity for ranking individuals according to usual intake and was reproducible (42) . The ToyBox study instrument was shown to be reproducible and was reported to have moderate relative validity when compared with 3 d diet records (137) .…”

“…No details ‡ The reliability and content validity of the child questionnaires were tested separately in all participating countries (143) Reliability tested using a test-retest design was used by comparing data from two completions of the questionnaire conducted 1 week apart (130) No reliability data for F&V EYHS (30,117) Cross-sectional Children (n ≈ 4000) 9 and 15 years 4 (Denmark, Portugal, Estonia, Norway) (sourced study involves only Sweden)…”

“…Of the studies which were validated or tested for reproducibility and fulfilled inclusion criterion 1 (Table 1), validity and reliability of the FFQ was assessed using biomarkers (63,126) , FFQ (52) , food records (42,53,80,(128)(129)(130)(131)(132)137,138) or 24 h recalls (24-HDR) (36,38,80,129,135) as the reference method. In fifteen studies, validity was assessed by crude correlations (35,36,38,42,53,63,80,126,128,130,132,137,138) , energyadjusted correlations (52,53,126,129) , de-attenuated correlation coefficients (36,38,129,137) , mean or median differences in F&V consumption (35,36,38,42,52,53,80,…”

Fruit and Vegetables: Intake and Sociodemographic Determinants among Portuguese Mothers

“…The instruments were translated into national languages (and translated back to English) taking into account the cultural appropriateness for the subjects, and tested for reliability and validity in multiple pilot tests prior to final administration. More details about this are given elsewhere [27,28,29]. …”