[Design and validation of a questionnaire to assess dietary behavior in Mexican students in the area of health].

INTRODUCTION: The dietary behavior (DB) establishes the relationship between the human being and foods and has an influence on nutrient intake and, therefore, it contributes to the health or disease status of a population, even among college students. There exit some validated instruments to assess food and nutrients intake, but there are very few assessing DB.
OBJECTIVE: To design and validate a questionnaire to assess DB in Mexican college students.
METHODS: According to the literature and Reasoned Theory, a questionnaire assessing DB was designed. Its logic and content validity was determined by expert assessment. It was applied on two occasions with a 4-week interval to 333 students from the University of Guadalajara coursing the sixth semester of Medicine or Nutrition. The reproducibility was assessed by means of the interclass correlation coefficient. The construct validity and the internal consistency were calculated by Rasch analysis, for both the difficulty of the items and the subjects' capability.
RESULTS: The questionnaire finally included 31 questions with multiple choice answers. The interclass correlation coefficient of the instrument was 0.76. The Cronbach alpha was 0.50 for the subjects' capability and 0.98 for the internal consistency of the items. 87.1% of the subjects and 89.8% of the items had INFIT and OUTFIT values within acceptable limits.
CONCLUSIONS: The present questionnaire has the potentiality of measuring at low cost and in a practical way aspects related with DB in college student with the aim of establishing or following-up corrective or preventive actions. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.