• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.423-429
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• 1998

This study examined within- and between-person variation in nutrient intakes in order to estimate the degree of precision in dietary assessment among 37 males and 46females whose mean age was 70.4 years old. To collect dietary data, each subject was interviewed 5 or 6 times using a 24-hour recall method during a 3 month period. Within- person variation ranged from 23.5% to 101.2%. Lower values of within-person variation were observed in energy, carbohydrated, protein and phosphorous while higher value was observed in vitamin A. Between person variations of nutrient intakes ranged 12.6-23.5% in most nutrients. With 1 day dietary data, observed nutrient intakes were estimated to within 6-25% of the group's usual9true) intakes and 52-198% of the individuals' usual intakes. The values of these maximum percentage deviations became smaller when the number of dietary recalls increased. The results of this study suggest that the Korean elderly subjects appear to have a slightly less diverse diet compared to young Korean women. Within persons, intakes of nutrients largely from animal sources were more variable for the Korean elderly than for their counterparts in Western countries. This study also implies that commonly used 1 day dietary study may be appropriate for assessing group means of nutrient intakes, but clearly not appropriate for assessing individual's nutrient intakes.

• Journal of Nutrition and Health
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• v.33 no.4
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• pp.429-437
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• 2000

Contributions of specific foods to absolute intake and between-person variance in 13 nutrients were examined to develop a short food frequency questionnaire (FFQ) for the Korean elderly using dietary data collected by a semiquantitative FFQ with 96 food items. The contributions of specific foods to 90% absolute nutrient intake were measured by assessing their percentage to the total consumption of a nutrient by our samples(n=98). To assess the contribution of the foods to the between-person variance in intake of each specific nutrient, stepwise multiple regression was performed. Cumulative R2 served as the measure of contribution to variation in intake. The most important food source of absolute intake was rice for energy and protein. Important foods of between person variance contribution include bread for energy and pork for protein. Important foods of absolute and variance contribution of nutrient intake were similar for fat(noodles including jajangmyun and kalguksu), calcium(anchovy and milk) and vitamin A (carrot). The number of foods necessary to account for the variation in nutrient intake among older people in Korea differ considerably by nutrient: 18 - 43 and 8-26 foods were accounted for the respective 90 and 80% of absolute intake depending on nutrients. Carbohydrates and vitamin A and C had relatively a few major sources, thus may be assessed well by a small number of foods. Conversely, iron, potassium and B vitamins appear to need longer lists of foods. Fewer numbeer (6 - 12 and 4 - 9) of foods were required for the corresponding percentages of between-person variation for all nutrients. Depending on nutrients, 0.980-0.995 and 0.924-0.987 were respective correlation coefficients of nutrient intakes measured by 96 food items with those by lists of foods for 90% and 80% of absolute intake contribution. These findings suggest that an incomplete food list on the basis of its contribution to absolute and between person variation intakes may still be effective in discriminating among individuals. The results of this study may be useful in the design and use of dietary questionnaire.

• Journal of Nutrition and Health
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• v.33 no.8
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• pp.882-889
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• 2000

This study was conducted to examine contribution of specific foods to absolute intake and between-person variation in nutrients consumed by 2037 adults living in Korean rural area using one day 24-hour recall method. To measure contribution of food to absolute nutrient intake, all foods consumed were ranked by percentages calculated as the sum of the nutrient intake contributed by a given food divided by the total nutrient intake from al categories. To assess between-person variability in nutrient intake, stepwise multiple regression analysis was used with total nutrient intake from al foods as the dependent variable and the nutrient amount from each of all foods as independent variables. The kind and the number of foods necessary to account for the variation in nutrient intake among persons varied significantly depending on the nutrient. The nutrients contributing more than 80% of total intake with a few number of food items were ${\beta}$-carotene(ll), vitamin C(15) and vitamin A(16). Foods sometimes overlooked as important sources were found in some instances to be quantitatively important to population intake. Even though rice and Korean cabbage kimchi do not contain much nutrients in quantity, they made a major contribution to most nutrient intake of subjects because of large serving size and high frequency of intake. The food items and contributing order for between person variance was different from those of absolute intake. A large fraction of the variability of nutrient intake in this population was explained by a small number of foods. Fewer foods were required to explain a given proportion of the between-person variance in intake than to account for the same proportion of the popylation\`s total intake. These data may be useful in the development of dietary assessment instrument and in nutrition education. (Korean J Nutrition 33(8) : 882-889, 2000)

• Korean Journal of Community Nutrition
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• v.13 no.5
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• pp.701-712
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• 2008

The purpose of the present study was aimed to identify dish items applicable in developing dish?based food frequency questionnaire (DFFQ) for a hypertension study of Koreans. The 24-hour recall data of 4,401 subjects aged $20{\sim}65$ years from the 2001 Korean National Health and Nutrition Examination Survey were used for the analysis. Logistic regression model was used to identify the nutrient related with hypertension. Energy, fiber, sodium, calcium, carotene, vitamin B1 and vitamin C were associated with hypertension. Selection the top 30 dish items for these seven nutrients was performed based on their degree of contribution in supplying nutrients in terms of the cumulative percent contribution (cPC), as well as on their degree of explanation for between?person variation, in terms of the cumulative regression coefficient (cMRC). Rice supplied 43% of total energy consumption. Korean cabbage and radish kimchi were two major sources of sodium and it also covered the 27% of between person variation of sodium intake. Soybean paste soup and single item of orange?colored fruits supplied 43% of total vitamin C intake for Koreans and it covered the almost 79% of between person variation among the Korean population. Korean cabbage kimchi was the major source of fiber, calcium, sodium, carotene, and vitamin C for Koreans. In summary, the top 30 selected dish items supplying the 78% to 89% of the 7 nutrients. Those items also covered the 79% to 94% of between person variation of the 7 nutrients consumption. Therefore, the selected 30 dish items in each categories of nutrient could be applicable in developing dish based food frequency questionnaire for hypertension study.

• Journal of Nutrition and Health
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• v.30 no.3
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• pp.349-359
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• 1997

This study was designed to study sources of variability(subjects, day by day, season, day of week, sequence, number of repeated days, compliance etc.) in multiple 24-hour dietary recall method. Dietary intakes of college women in Seoul were obtained using 24-hour dietary recalls, consecutive 7 days, 4 times for 1 year. The result of this study shows that 1) the reproducibility of multiple 24-hour recalls is low(intraclass correlation coefficient<0.3), 2) the intraindividual variations of all nutrients are more than 80%, 3) the major components of variation are interindividual vriability and intraindividual variability(within person variability and methodologic error). There were small but statistically significant season and compliance effects. 4) the ratio within-person varation to between-person variation for absolute and transformed nutrient intakes except some nutrients such as vitamin A, vitamin C, energy from protein and fat etc, was less than 1.7 the minimum numbers of days needed in 24-hour dietary recalls to estimate usual intake for this group were 1 to 21 days. And the numbers of days needed to get the usual intake of an individual varied among individuals and within individuals for different nutrients, ranged from 1 days for log carbohydrate(% energy) to 470 days for Na. 6) There were greater than 0.7 correlation coefficients between the average nutrient intakes of 12 days and intakes of 28 days. Therefore, it was desirable to take the 24-hour recall more than 12 times, repeating 3 days every season.

• Journal of the Korean Society of Food Culture
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• v.9 no.4
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• pp.401-409
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• 1994

The use of food frequency questionnaire to estimate dietary intake has become widespread in epidemiologic studies. It has been suggested that knowledge about a person's usual serving size of each food, in addition to consumption frequency, will improve the accuracy of this method. This study was performed to investigate the nutritional status and one sowing sizes of commonly consumed dishes in Korean college women. Intakes of dish or food in 156 college women were measured by 7-day weighed food records in May, 1992 and May, 1993. For each dish or food, variance in one serving size was partitioned into within-person(intraindividual) and between-person(interindividual) components. All nutrient intakes except vitamin A and vitamin C were less adequate. The major dish groups which contributed to the most daily nutrient intakes were boiled rice, bread, fruits, dairy product, and biscuit and snack groups. In more than 50% of dishes, the within-person variation was greater than between-person variation. And the variety and amount of food which was used in one dish were too variable to make standard recipe.

• Journal of Nutrition and Health
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• v.35 no.2
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• pp.250-262
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• 2002

This study was conducted to develop a simple flood frequency questionnaire (FFQ) based on the results of contributions of specific floods to absolute intake and between-person variance in nutrients using semi-quantitative FFQ with 93 flood items. The subjects were 554 healthy adults for development of a simple FFQ, and 37 students for a validation test of a developed simple FFQ. The contribution of specific floods to 80% absolute nutrient intake was measured by assessing their percentage in total consumption of a nutrient. To assess the contributions of floods to the between-person variance in the intake of each specific nutrient, stepwise multiple regressions were performed. The number of floods necessary to account for the respective 80% of absolute intake was 11-36, depending on the nutrient, while flower floods (5-16 floods) were required for the corresponding percentage of between-person variation for all nutrients. Important floods for between-person variance include Tangsuyuk (pork) and snacks for energy and fat, fish for protein and polyunsaturated fatty acids (PUFA) and snacks for carbohydrates. Spearman correlation coefficients between 93-itemed FFQ and 63-itemed FFQ ranged from 0.91 for vitamin A to 0.99 for fat in the population data used in developing a simple FFQ. Also, the correlation coefficients between the two FFQs were 0.82-7.92 in the population for the validation test. This study suggests that useful information on dietary intake could be obtained using a simple semi-quantitative FFQ in a large-scale dietary survey in Korea.

• Nutrition Research and Practice
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• v.13 no.4
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• pp.323-332
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• 2019

BACKGROUND/OBJECTIVES: The aim of this study was to analyze specific foods influencing absolute nutrient intake and between-person variations of nutrient intake among Korean preschoolers. SUBJECTS/METHODS: This study included 2,766 participants aged 1-5 years in the 2009-2013 Korea National Health and Nutrition Examination Surveys. Dietary data were obtained from a 24-h dietary recall method. Major food sources of absolute nutrient intake were evaluated based on percent contribution of each food. To assess the contribution of specific foods to between-person variations in nutrient intake, stepwise multiple regressions were performed and cumulative $R^2$ was used. RESULTS: White rice and milk were main food sources of energy, protein, carbohydrate, phosphorus, iron, potassium, thiamin, riboflavin, and niacin. The percentage of fat contributed by milk was 21.3% which was the highest, followed by pork, soybean oil, and egg. White rice accounted for 25% and 40% of total variability in total energy and carbohydrate intakes, respectively. About 39% of variation in calcium intake was explained by milk while 40% of variation in phosphorous intake was explained by cheese. The top 10 foods contributing to between-person variations in nutrient intakes were similar with food items that mainly contributed to absolute nutrient intakes. The number of foods explaining 90% of absolute amounts of nutrient intakes varied from 28 for vitamin A to 80 for iron. CONCLUSIONS: This study identified specific foods that contributed to absolute nutrient intakes and between-person variations in nutrient intakes among Korean preschoolers. Our findings can be used to develop dietary assessment tools and establish food-based dietary guidelines for young children.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.892-900
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• 1995

Dietary data of 538 middle school students have been analysed to identify the contribution of specific foods to absolute intake and between-person-variance in nutrient consumption. The 24-hour-dietary-recall method had been used to collect the data required. Contribution of specific foods, in terms of ranking order for both absolute intake and between-person-variance have been observed. Ranking order of food for absolute intake was given based on the percen of contribution whereas the ranking order of foods for between-person-variance was given based on the percent of contribution whereas the ranking order of foods for between-person-variance was given based on a coefficient fo variation. As a result, for most of the nutrients(except cholesterol), the ranking order of foods for the between-person-variance was quite different from that of absolute intake. The results indicate that to identify between-person-variance of nutrient intake in an epidemiology study, foods with a high ranking in between-person-variance should be included in developing the food frequency questionnaires rather than foods which showed a high ranking in absolute intake.

• Journal of Community Nutrition
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• v.5 no.2
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• pp.72-82
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• 2003

We here outlined our study on the variations in intake of nutrients based on four season 7 consecutive day weighed diet records (WDRs) from 80 Japanese female dietitians in 1996 - 1997. Furthermore, we reviewed Japanese, Korean and international articles investigating variability in consumption of foods as well as nutrients. The relative contributions of variation for all nutrients by person were greater than those by day, week and season. Within individual variances were greater than that between individual variances, being generally observed in Korea and in the world. The ratios of within- vs. between-individual variations ranged from 1.3-26.9 in our study, the ratios being greatest in Korean, followed by Japanese and western people. Based on within individual coefficients of variation, minimal days necessary for estimating nutrient consumption per person within 10％ (20％) of the true mean with 95％ confidence intervals were estimated. They ranged from 10-35 (3-9) days for energy and major nutrients and 15-640(4-160) days for micro-nutrients. Two Japanese studies reported that the ratios for foods were as a whole greater than those for nutrients, except for cereals, rice and milk. (J community Nutrition 5(2) : 72-82,2003).