한국 청소년 대상 반정량적 식품섭취빈도조사지의 개발과 서면 및 웹 기반 적용에서의 평가

Abstract

The purpose of this study was to develop a dish-based semiquantitative food frequency questionnaire(FFQ) for Korean adolescents and evaluate its reproducibility and validity. We also aimed to construct web-based dietary evaluation system applying the developed FFQ for Korean adolescents and examine its applicability in the context of reliability and validity. Based on 24-hour dietary recall data from the 4th Korean National Health and Nutrition Examination Survey(KNHANES), we developed a FFQ with 71 items. From quota sample of 160 adolescents recruited using gender and age group as stratification variables, 153 participated in the complete data collection process. The FFQ was administered to each subject twice, at an interval of 3-4 weeks, to evaluate the test-retest reliability. The validity of the FFQ was assessed relative to 8-day food record data. The study findings demonstrated the FFQ`s satisfactory reproducibility. Spearman correlation coefficients ranged from 0.64(for β-carotene) to 0.81(for protein). From cross-classification analyses, the proportion of subjects in the same intake quartile was highest for protein(65.4%) and lowest for vitamin A(47.1%). The consistency between the first and second FFQs was also assessed using weighted kappa values. The highest and lowest values for nutrients were 0.67 for protein and 0.47 for energy, respectively. With regard to validity analysis, Spearman correlation coefficients raged from 0.27(for vitamin A and fiber) to 0.90(for energy). From cross-classification analysis, the proportion of subjects in the same intake quartile was highest for energy(57.4%) and lowest for β-carotene(26.5%). The proportions of subjects in the opposite categories between the first FFQ and 8-days food record data were generally low within the range from 0.7%(for energy and carbohydrate) to 13.2%(for β-carotene). The highest and lowest weighted kappa values for nutrients were 0.07 for β-carotene and 0.62 for energy. A web-based FFQ system was designed in a comprehensive approach, incorporating not only dietary data survey but also up-to-date nutrition information and individualized eating behavior guidelines. Major components include log-in & membership, dietary data entry, nutrition information, message board and my page. A convenience sample of 50 boys and girls aged 12∼18 years agreed in the study participation and completed the FFQ twice and 3 days of dietary recall on the developed website during a two-month period. The web-based FFQ's reliability and validity was examined using correlation and cross classfication analysis. We also measured participants' subjective perception on the web-based dietary evaluation system`s usability, visual effect, understanding, and familiarity. Spearman correlation coefficients for reliability raged from 0.74(for vitamin A) to 0.94(for energy and protein). From cross-classification analysis, the proportion of subjects in the same intake quartile was highest for energy(82.0%) amd lowest for vitamin A(56.0%). The highest and lowest weighted kappa values for nutrients were 0.84 for energy and 0.58 for vitamin A, respectively. With regard to validity analysis, Spearman correlation coefficients raged from 0.34(for fiber) to 0.79(for energy). From cross- classification analysis, the proportion of subjects in the same intake quartile was highest for energy(59.6%) and lowest for vitamin C(21.3%). The proportions of subjects in the opposite categories between the first FFQ and 3-days diet recall data were generally low from 0.00%(for fat, phosphorus) to 10.6%(for niacin). The highest and lowest weighted kappa values for nutrients were 0.09 for vitamin C and 0.63 for energy. Average subjective perception on the web-based dietary evaluation system`s usability, visual effect, understanding, and familiarity were all found over 4 points out of 5 points. In conclusion, the dish-based semiquantitative FFQ developed in this study can be useful for grouping Korean adolescents according to major macro-and micronutrient intakes with reasonable reproducibility and validity via both paper-based and web-based administration. The FFQ can be used as a useful tool in different settings such as screening out high nutritional risk subjects and evaluating effects of nutrition intervention or counselling programs.