Development and simulated validation of a food-frequency questionnaire for the Colombian population
´ Leonelo E Bautista1,*, Oscar F Herran2 and Jane A Pryer3
Department of Population Health Sciences, University of Wisconsin Medical School, 610 Walnut Street, 703 WARF, ´ ´ ´ Madison, WI 53726-2397, USA: 2Centro deInvestigacion Epidemiologica, Observatorio Epidemiologico de Enfermedades Cardiovasculares, Universidad Industrial de Santander, Bucaramanga, Colombia: 3Royal Free and University College Medical School, University College London, Department of Primary Care and Population Sciences, UK Submitted 17 May 2004: Accepted 6 September 2004
Abstract Objective: To develop a food-frequency questionnaire (FFQ)useful for ranking of nutrient intakes. Design: Subjects consuming their regular diet completed 7 days of weighed intake registry (7-WIR). Foods for the FFQ were selected by stepwise multiple regression. The FFQ was then completed for each subject using data on individual food consumption from the 7-WIR. The correlation and agreement between the extrapolated FFQ and the 7-WIR data were assessedusing Spearman’s rank correlation coefﬁcients (rS) and Bland and Altman’s limits of agreement (LOA). Setting: Bucaramanga, Colombia. Subjects: We studied 97 randomly selected 20 –40-year-old subjects. Results: Sixty foods were selected for the FFQ. The 7-WIR and the extrapolated FFQ intake estimates correlated well. rS was 0.58 for energy, 0.53 for carbohydrate, 0.50 for total fat, and 0.48 forprotein. For micronutrients, rS varied from 0.46 (manganese) to 0.71 (vitamin B12). FFQ average intake estimates were 83%, 80%, 86.2% and 86.4% of 7-WIR estimates for energy, carbohydrate, total fat and protein, respectively. LOA for these nutrients ranged between 45% and 165%. FFQ micronutrient intakes were on average 96% (median) of those from the 7-WIR, and the median lower and upper LOA were 50% and203%. However, there was no indication that the degree of agreement varied with the level of intake. Conclusions: According to our simulated validation, this FFQ may be useful to rank subjects by nutrient intake. Its validity against standard independent measurements and its applicability to other subsets of the Colombian population should be carefully considered.
Keywords Nutritionalassessment Food-frequency questionnaire Weighed food registry Colombia
Dietary factors have a large impact on chronic disease morbidity and mortality1. There are few studies on the relationship between nutritional intake and the risk of chronic diseases in developing countries. In Colombia, as in other countries2, this is due mainly to the lack of valid, low-cost dietary assessment methods amenable forstudies in large populations. Use of dietary tools developed in other populations is not a proper alternative, since it is well known that methods validated in one population are not necessarily accurate in other groups, even from the same country, unless they are developed speciﬁcally for this purpose3. Moreover, the use of methods with low validity seriously attenuates the associations betweennutritional intake and disease in epidemiological studies, a problem known as regression dilution4.
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Although different methods can be used to evaluate individuals’ nutritional intake in epidemiological studies, food-frequency questionnaires (FFQs) have been the tool used most frequently during past decades, because they are easy to apply inlarge populations and have relatively low cost5. An FFQ for a speciﬁc population is usually developed by modifying existing FFQs validated in a related population. Such an approach was not feasible for our population of interest, since no FFQ had previously been developed in Colombia. Here we report the results of a study aimed to develop an FFQ based on the direct quantiﬁcation of foods and...