Abstract
Objectives
Fruit and vegetable (F&V) consumption is generally associated with the prevention of major chronic diseases. For monitoring purposes, public health researchers require short but reliable and valid questionnaires to assess F&V consumption. The aim of the present study was to validate a brief one-page self-administered fruit and vegetable questionnaire (FV-Q) for obese and non-obese populations.
Methods
The validation study was conducted from 2004 to 2006, among a sample of 350 obese and non-obese French-speaking participants. The six-item FV-Q was designed to measure F&V consumption over a seven-day period. It was validated against an interviewer-administered Food Frequency Questionnaire (FFQ) by means of correlation analysis and computing of epidemiologic indices. The analyses were performed separately for obese and non-obese individuals in order to account for potential different reporting patterns and the absence of such validation in obese populations. All the analyses were performed during 2007.
Results
For obese and non-obese participants, the Pearson correlation coefficients between the FV-Q and FFQ were, respectively, r = 0.66 (p<0.0001) and r = 0.65 (p<0.0001) for the mean daily intake. Values for sensitivity and specificity were 88.5% and 63.6% for obese individuals and 80.0% and 65.6% for non-obese individuals, respectively. Positive predictive values were moderate in both groups, whereas negative predictive values were very good. Overall, results were very similar for obese and non-obese individuals.
Conclusions
This brief F&V questionnaire can be used to identify people requiring nutritional counseling. Moreover, it can be used for both obese and non-obese populations.
Keywords: Fruit, vegetables, questionnaires, validation studies
Résumé
Objectifs
La consommation de fruits et de légumes est généralement associée à la prévention des grandes maladies chroniques. Dans un but de surveillance, les chercheurs en santé publique ont besoin de questionnaires courts mais fiables pour déterminer cette consommation. Nous avons voulu valider le QFL, un questionnaire auto-administré d’une seule page permettant de mesurer la consommation de fruits et de légumes dans des populations obèses et non obèses.
Méthode
Notre étude de validation a été conduite entre 2004 et 2006 auprès de 350 participants obèses et non obèses de langue française. Le questionnaire en six points mesure la consommation de fruits et de légumes sur une période de sept jours. Il a été validé par rapport au FFQ (un questionnaire sur la fréquence de consommation des produits alimentaires administré par entrevue) au moyen d’une analyse de corrélation et d’indices épidémiologiques. Pour pallier d’éventuelles différences dans la façon de répondre au questionnaire et permettre son usage auprès d’une population obèse, les analyses ont été effectuées séparément pour les sujets obèses et non obèses. Toutes les analyses ont été effectuées pendant l’année 2007.
Résultats
En ce qui concerne la consommation quotidienne moyenne, les coefficients de Pearson entre le QFL et le FFQ étaient de r = 0,66 (p<0,0001) pour les participants obèses et de r = 0,65 (p<0,0001) pour les non-obèses. Les valeurs de sensibilité et de spécificité étaient, respectivement, de 88,5 % et 63,6 % pour les sujets obèses et de 80,0 % et 65,6 % pour les non-obèses. Les valeurs prédictives positives étaient modérées dans les deux groupes, tandis que les valeurs prédictives négatives étaient très bonnes. En général, les résultats étaient similaires chez les obèses et les non-obèses.
Conclusion
Ce bref questionnaire mesurant la consommation de fruits et de légumes peut être utilisé pour identifier les personnes qui nécessitent de l’assistance nutritionnelle. De plus, il peut être utilisé autant auprès de populations obèses que non obèses.
Mots clés: fruits, légumes, questionnaires, validation
Footnotes
Acknowledgements: Gaston Godin holds a Tier 1 Canada Research Chair in Health Related Behaviour, Laval University. This work was supported by a grant from the Canadian Institutes of Health Research (CIHR) — New Emerging Teams Programs (NET) (#OHN-63276).
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