• Korean Journal of Community Nutrition
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• v.3 no.2
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• pp.273-280
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• 1998

This study was designed to estimate the improvement of Validity for food frequency questionnaire(FFQ) by offering multiple choice portion size in developing a questionnaire. Validity of the two methods(food frequency questionnaire I=FFQ I & Food frequency questionnaire II=FFQ II) was tested in comparison with reference method of the 7-day weighed record(7DWR). Dietary consumption data of the three methods(FFQ I, FFQ II & 7DWR) were collected from 101 female university students for the analysis. Validity was measured in two categories : One was the nutrient intake value from the three methods, the other was the identification of between individual variation within the group. Spearman's rank order correlation test and distribution graphs were used for the analysis. The result showed that individual intake value of the FFQII was closer to that of the 7DWR than that of the FFQ I.Spearman's rank order correlation between the FFQII and the 7DWR did not show any improved correlation. The distribution graphs of nutrient intake derived from both the FFQ I and the FFQII were different from that of the 7DWR. Therefore, it could be suggested that single one portion size food frequency questionnaire is an equally efficient method as a multiple choice food frequency questionnaire to be adopted in epidemiologic studies.

• Journal of Nutrition and Health
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• v.30 no.5
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• pp.520-528
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• 1997

This study was conducted to develop a food frequency questionnaire for an epidemiological study of dietary patterns and nutrient intake among Koeran American. A random sample of 101 Korean Americans between the ages of 17 and 71 residing in New York and New Jersey was interviewed by the method of 24-hour dietary recall. The foods Korean Americans consumed most frequently were rice (91% of the population), kimchee (81%), coffee(59%), bread(49%), apple(45%), bean sprouts (33%), milk (30%), dried anchovies (27%), eggs(27%), juice (26%), bulgogi, and soybean paste soup (24%, equally. The classification of food items standardized portion sizes were according to both Block's questionnaire and the standardized portion sizes by the Korean Nutrition Association. The value of this food frequency questionnaire is that it can accurately estimate dietary food patterns and nutrient intake among Korean Americans for epidemiological studies. It could also potentially be modified to study the relationship between specific diseases and food intake in the future.

• Korean Journal of Community Nutrition
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• v.7 no.4
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• pp.484-494
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• 2002

This study was conducted to validate the semi-quantitative food frequency questionnaire that was developed to assess the intakes of fatty acids, as well as energy, carbohydrates, fat, protein, minerals and vitamins in Korean adults. The validity of the semi-quantitative food frequency questionnaire was tested on 78 subjects (31 men,47 women) aged 34 to 66 years. The semi-quantitative food frequency questionnaire included 93 food items and was validated on two 3-day dietary records. The mean intakes and the Spearman Correlation Coefficients between the semi-quantitative food frequency questionnaire and the two 3-day dietary records were analyzed for each nutrient and food group level. The mean nutrient intakes obtained from the semi-quantitative food frequency questionnaire were estimated to be greater than those of the two 3-day dietary records. The Spearman Correlation Coefficients between the energy-adjusted nutrient intakes from the semi-quantitative food frequency questionnaire and the two 3-day dietary records ranged from 0.24 for polyunsaturated fatty acids to 0.55 for fat in men and from 0.29 for polyunsaturated fatty acids to 0.55 for saturated fatty acids in women, respectively. The Spearman Correlation Coefficients for food intake ranged from 0.11 for teas and beverages to 0.58 for grains and their products in men,-0.04 for potatoes and starches to 0.73 for milk and dairy products in women. Foods consumed regularly had lower intra-person variation and tended to have higher observed correlation coefficients. These results indicate that the semi-quantitative food frequency questionnaire is a useful tool for estimating nutrient intakes, particularly of total fat and saturated fatty acid intakes.

• Korean Journal of Community Nutrition
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• v.2 no.3
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• pp.349-365
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• 1997

Using data obtained from 1, 473 adults aged 18-68 yrs, residing in large cities and by use of a semi-quantitative food frequency questionnaire, we assessed the relative importance of various foods as indicators of both the amount and the variability of selected nutrient intake to develop a simple food frequency questionnaire. Since Cronba- ch's alpha value of the questionnaire including 78 food items was 0.76, the reliability of this questionnaire was acceptable. A large fraction of the variability of nutrient intake in this population could be explained by the small number of food items. The estimation of dietary nutrient intake such as total calories or protein content, which are derived from almost all foods, will require more food items with nutrients such as calcium or vitamin A, which are concentrated in a few food items. A dietary history ascertaining the intake of as few as 5-19 food items mighted be all needed in order to determent the associa- tion between disease outcome and the intake of a single nutrient. There was certainly a high level of agreement with nutrient intake by the sbujects who were cross-classified by quartiles of nutrient indices based on all the food items(78) and by quartiles of nutrient indices based on food items selected by stepwise multiple regression for selected nutrients. The data provided further evidence that useful information on dietary intake over an extended period can be obtained by a simple and relatively inexpensive food frequency questionnaire.

• Journal of Nutrition and Health
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• v.33 no.2
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• pp.202-215
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• 2000

Intake frequency of one food is often associated with other food items, but few studies examined the relationship of food intake frequency among food items. Finding the relationship among intake frequencies of different food might be useful to understand the food intake patterns of population and correlated foods would be used as an indicators of another food intake. Relationship of food intake can be also applied to make a more simple and useful form of food frequency questionnaire to assess the association between diet and various diseases. The objective of this study was to examine the correlation of intake frequency among food items in food frequency questionnaire (FFQ). A FFQ with 84 food items was administered to 14533 Korean males who 40-65 years of age participating Korean cancer research survey. Data fromm 7647 subjects who completed FFQ were used to examine correlation among food items with three different methods-log linear regression models, Spearman correlation coefficients and cell frequency distribution. To examine the rank correlation, coefficients were calculated by Spearman correlation after scoring the frequency categories. Three most correlated foods were selected in every food intems by three methods each. In most food items, there was positive correlatin, except cooked rice and cooked brown rice, in intake frequency between foods that belonged to similar food groups. But serveral food items-Sausage (processed fish, cheese), Milk (whilte bread, orange juice), Soymilk(other juices), Cheese (pizza, butter), and Coffee(thick beef soup)-showed correlation among totally different food groups. Two sets of food items which were selected by log linear regression model and Sperman correlation coefficients were compared. There were exactly three common foods in 18 food items, 2 common foods in 47 items, 1 common food in 16 items and no common food in 3 items among 3 ranked foods. Three sets of selected food were compared. There were exactly three common foods in 5 food items, 2 common foods in 21 items, 1 common food in 34items and no common food in 24 items among 3 ranked foods. These results indicate that certain patterns exist among intake frequencies of specific food items in the FFQ. More researches are suggested to understand the relationshiops among the intakes of foods so that this information can be used in developing better FFQ or analyzing missing items from self-administered FFQ.

• Journal of Nutrition and Health
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• v.40 no.6
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• pp.566-575
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• 2007

The purpose of this research was to understand how individuals reflect on the frequency and quantity of foods that they consume. Participants selected 5 males and 15 females aged 30 years or older were first interviewed on the frequency of their food consumption. Then based on this data, they were given a cognitive interview using the method of verbal proving. The individual cognitive interviews were recorded with consent while being conducted after complete approval by the Seoul National University Institution Review Board. The recorded material was evaluated using a thematic analysis after transcribing them into text. By analyzing stages of reflection, the major barriers to make the device difficult are revealed: 1) More difficulty in remembering events over the course of a full year due to diversification in the types of food that people consume 2) difficulty calculating the average for seasonal foods 3) difficulty estimating the amount of consumption from the photos presented 4) difficulty estimating amount of consumption from the quantity presented 5) difficulty processing foods that people think are healthy and foods are unhealthy simultaneously 6) difficulty having to consider foods where target food goes in as an ingredient; 7) difficulties arising from having to increase frequency when the amount consumed is higher than the quantity that is presented 8) difficulty having to combine the frequency and quantity of each food item when numerous foods are clustered into one category. These findings show that the less participants were involved in cooking, the more diverse their eating habits were, and the more they tried to adhere to rules of filling out the questionnaire, the more it was difficult for them to come up with an answer to the question being asked. It therefore seems necessary to construct a Food Frequency questionnaire that is attentive to these problems that arise from the recall stages.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.3
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• pp.409-420
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• 2009

This study investigated preferences toward soybean-based foods and levels of dietary isoflavone intake in female adults living in Daegu. In order to determine the subjects' attitudes toward soybean-based foods their degrees of recognition and preference along with intake frequency were examined. To estimate their isoflavone intake levels, a food frequency questionnaire and the 24-hour recall method were used. The average age, height, weight, and BMI of the subjects were 47.3 years, 159.6 cm, 56.4 kg, and 22.1 kg/$cm^2$, respectively. And their mean energy, protein, dietary fiber, calcium, and sodium intakes were 1,871.9 kcal, 81.1g, 23.2 g, 604.7 mg, and 5.07 g, respectively. The average amount of isoflavones consumed from soy foods was 29.49 mg/day(daidzein 13.14 mg/day and genistein 16.35 mg/day) as assessed by food frequency questionnaire, and by the 24-hour recall method the average amount was 22.97 mg/day (daidzein 10.10 mg/day and genistein 12.87 mg/day), showing that the food frequency questionnaire assessment amount was 6.52 mg higher than that by 24-hour recall method. The major food sources of the isoflavones were soybean paste and soybeans. For the subjects' degrees of recognition of soybean food, soybean paste received the highest score among the items. The results also showed that the most preferred soybean-based foods were soybean paste stew and soybean paste soup. Furthermore isoflavone intake was significantly higher in the postmenopausal women than in the premenopausal women. Overall, these data help elucidate the patterns and determinants of soy food consumption and also provide an assessment of dietary soy isoflavone intake in Korean women.

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.220-230
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• 1998

The purpose of this study was to develop and validate the Food frequency questionnaire (FFQ) for dietary studies of Koreans. One hundred and five food items for the Food frequency questionnaire were selected based on information of frequently consumed foods from National Nutrition Survey Reports and on raw data from a dietary survey on diabetic patients. Frequency of consumption was determined through nine categories ranging from more than three times a day to almost never to indicate how often the specified amount of each food item was consumed during the past month. Three portion sizes were given for each food item(small, medium or large) with respect to a stated medium portion. Seventy-three healthy women served for the validation study. They completed both the FFQ and a 3-day diet record. The FFQ estimate of mean nutrient intake was higher by 10-20% than that of the 3-days diet record and the Spearman correlation coefficients between the two methods ranged from 0.26 to 0.59 . The degree of agreement was from 36% to 38% when nutrients intake assessed by the FFQ and 3day diet record were classified within the same quintile. On the whole , the result of this study seemed to be in good agreement with other studies. Therefore the FFQ developed in this study is considered to be a reliable tool in assessing the dietary habits of Korean.

• Korean Journal of Community Nutrition
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• v.13 no.1
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• pp.111-124
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• 2008

This study was conducted to develop a computerized food frequency questionnaire (FFQ) for assessing nutritional status of women of child-bearing age. Computerized food frequency questionnaire (FFQ) that reflect intakes of energy, carbohydrate, fat and protein was developed for women of child-bearing age. This FFQ is composed of 61 foods or food groups containing 192 dish items. To estimate of energy intake easily, we have developed a computer program that can be viewed on a computer screen in an actual size of dish items. Nutrient intakes of the last three months by the FFQ was validated with comparing the result of a 3-day diet record through 92 college students aged from 20 to 30. The level of energy, carbohydrate and sodium of estimating by the FFQ method was significantly higher than the level of a 3-day diet records method (p < 0.01). Pearson's correlation coefficients between the two methods were 0.50 for carbohydrate (p < 0.01), 0.55 for energy (p < 0.01) and 0.56 for protein (p < 0.01). Spearman's correlation coefficients were 0.53 for carbohydrate (p < 0.01), 0.55 for energy (p < 0.01) and 0.52 for protein (p < 0.01). The percent of subject in the lowest quartile in a 3-day diet record belonged to the first and second lowest quartile in food frequency questionnaire is 78.2% in energy, 91.3% in carbohydrate, 78.2% in protein, 69.5% in fat. Also, the percent of subject in the highest quartile in a 3-day diet record belong to the first and second highest quartile in food frequency questionnaire is 78.3% in energy, 73.9% in carbohydrate, 82.6% in protein, and 73.9% in fat. On the whole, the result of this study seemed to be in good agreement with other studies. Therefore, the FFQ developed by this study is considered to be a reliable tool to assess nutrients and food intakes for women of child-bearing age.

• Korean Journal of Community Nutrition
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• v.1 no.3
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• pp.376-394
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• 1996

This study evaluated the reproducibility and validity of the self-administered semiquantitative food frequency questionnaire used in a large prospective cohort study(Korean Cancer Research Survey) in middle-aged men. The questionnaire was administered twice at an interval of approximately two years(December, 1992-January, 1995), and four or five 24-hour recalls for each subject were collected at intervals of approximately three months. The results were as follows; 1) Although the distributions of the data estimated by the questionnaire were somewhat wider, the mean nutrient intakes of group estimated by our questionnaires and the multiple 24-hour recalls were roughly comparable. 2) The reproducibility determined by correlation of absolute(unadjusted nutrient intake) and calorie adjusted nutrient intakes from two semiquantitative food frequency questionnaires were more than 0.5, and the weighted kappa values were more than 0.4. 3) The Pearson correlation coefficients between unadjusted nutrient intakes values were average 0.40 on the average(Ca, 0.13-Carbohydrate, 0.58) at the first questionnaire vs. 24-hour recalls, and 0.28 at the second questionnaire vs. 24-hour recalls. The spearman rank order correlation coefficients were similar. When energy intake was adjusted, there was a slight reduction : 0.28 at the second questionnaire, 0.25 average on the second. In order to correct the measurement error of 24-hour recall data, the deattenuated correlation coefficient was calculated. It averaged 0.53 on the first questionnaire, 0.37 on the second questionnaire for unadjusted nutrient intake. for calorie-adjusted nutrient intake, it averaged 0.44 on the first questionnaire, 0.37 on the second questionnarie. 4) There was lower agreement(k<0.4) between the questionnaries and the 24-hour recalls. And the subjects classified in the same quartile by 24-hour recalls and first questionnaire were average 37$\%$(energy-adjusted values) and 40$\%$(unadjusted values) on the average. More than k10$\%$(average) of subjects were in the extreme quartile of the questionnarie and 24-hour recall method. But 8.2$\%$(average) of subjects classified in the lowest quartile of unadjusted nutrient intake level by the 24-hour recalls were in the highest quartile by the first questionnaire. These data indicate that our self-administered semiquantitative food frequency questionnarie is reproducible. Correlation coefficients comparing nutrient intakes measured by two different dietary assessment methods were less than 0.5. The validity of our questionnarie is not high enough.