Korea National Health and Nutrition Examination Survey, 20th anniversary: accomplishments and future directions / 한국역학회지

The Korea National Health and Nutrition Examination Survey (KNHANES) was initiated in 1998 to provide evidence for the development and evaluation of health policies and programs. The Korea Disease Control and Prevention Agency is responsible for the KNHANES and has conducted it as a series of surveys. Over the past 20 years, efforts to produce accurate, timely, and nationwide health statistics have been refined by establishing a continuous annual survey system with full-time field staff, incrementally expanding survey components, collaborating with relevant academic societies for quality control, and revising the survey methods. Additionally, the utility of the collected data was increased by linking the KNHANES data with related data from other government agencies or institutions and making the overall data publicly available on the official website of KNHANES (https://knhanes.kdca.go.kr). Additional long-term plans are being developed, including plans to continue producing nationwide health indicators and invigorating the utilization of the KNHANES data.

Trends in food and nutrient intake over 20 years: findings from the 1998-2018 Korea National Health and Nutrition Examination Survey / 한국역학회지

OBJECTIVES@#We aimed to examine the current status and trends of food and nutrient intake in the Korean population over the past 20 years using the data from the Korea National Health and Nutrition Examination Survey (KNHANES). @*METHODS@#We conducted a survey of 116,284 subjects over the age of one year in Korea, who participated in the KNHANES between 1998 and 2018. We collected data on the subjects’ intake for the day before using the 24-hour recall method. The annual percent change (APC) in the food groups and nutrient intake were calculated using SAS and Joinpoint software. @*RESULTS@#The intake of grains (APC=-0.4, p<0.05) and vegetables (APC=-0.8, p<0.05) was observed to decrease. In contrast, the intake of beverages, meat, dairy, and eggs increased. In particular, beverage intake increased by more than four times (APC=9.2, p<0.05). There was no significant change in energy intake. However, the proportion of energy intake from carbohydrates decreased by approximately 5%p (APC=-0.3, p<0.05), whereas that from fat increased by approximately 5%p (APC= 1.1, p<0.05). Additionally, there were decreases in the proportion of energy intake from breakfast and homemade meals and increases in the energy intake from snacks, dining out, and convenience food. The intake of vitamin C (APC=-3.2, p<0.05) and sodium (APC=-2.3, p<0.05) significantly decreased. @*CONCLUSIONS@#Over the past 20 years, there has been decreases in the intake of grains, vegetables, carbohydrates, sodium, and vitamin C and increases in the intake of beverages, dairy, meat, eggs, and fat. Since nutritional status is an important factor in the prevention and management of chronic diseases, it should be continuously monitored.

Korea National Health and Nutrition Examination Survey, 20th anniversary: accomplishments and future directions / 한국역학회지

The Korea National Health and Nutrition Examination Survey (KNHANES) was initiated in 1998 to provide evidence for the development and evaluation of health policies and programs. The Korea Disease Control and Prevention Agency is responsible for the KNHANES and has conducted it as a series of surveys. Over the past 20 years, efforts to produce accurate, timely, and nationwide health statistics have been refined by establishing a continuous annual survey system with full-time field staff, incrementally expanding survey components, collaborating with relevant academic societies for quality control, and revising the survey methods. Additionally, the utility of the collected data was increased by linking the KNHANES data with related data from other government agencies or institutions and making the overall data publicly available on the official website of KNHANES (https://knhanes.kdca.go.kr). Additional long-term plans are being developed, including plans to continue producing nationwide health indicators and invigorating the utilization of the KNHANES data.

Trends in food and nutrient intake over 20 years: findings from the 1998-2018 Korea National Health and Nutrition Examination Survey / 한국역학회지

OBJECTIVES@#We aimed to examine the current status and trends of food and nutrient intake in the Korean population over the past 20 years using the data from the Korea National Health and Nutrition Examination Survey (KNHANES). @*METHODS@#We conducted a survey of 116,284 subjects over the age of one year in Korea, who participated in the KNHANES between 1998 and 2018. We collected data on the subjects’ intake for the day before using the 24-hour recall method. The annual percent change (APC) in the food groups and nutrient intake were calculated using SAS and Joinpoint software. @*RESULTS@#The intake of grains (APC=-0.4, p<0.05) and vegetables (APC=-0.8, p<0.05) was observed to decrease. In contrast, the intake of beverages, meat, dairy, and eggs increased. In particular, beverage intake increased by more than four times (APC=9.2, p<0.05). There was no significant change in energy intake. However, the proportion of energy intake from carbohydrates decreased by approximately 5%p (APC=-0.3, p<0.05), whereas that from fat increased by approximately 5%p (APC= 1.1, p<0.05). Additionally, there were decreases in the proportion of energy intake from breakfast and homemade meals and increases in the energy intake from snacks, dining out, and convenience food. The intake of vitamin C (APC=-3.2, p<0.05) and sodium (APC=-2.3, p<0.05) significantly decreased. @*CONCLUSIONS@#Over the past 20 years, there has been decreases in the intake of grains, vegetables, carbohydrates, sodium, and vitamin C and increases in the intake of beverages, dairy, meat, eggs, and fat. Since nutritional status is an important factor in the prevention and management of chronic diseases, it should be continuously monitored.

Dietary Cholesterol Intake in the Korea National Health and Nutrition Examination Survey (KNHANES) VI (2013–2015) / 대한지역사회영양학회지

OBJECTIVES: The aim of the study was to assess the intake of dietary cholesterol and its major food sources in the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: A total of 20,671 nationally representative sample who had 24-hour recall data from the KNHANES VI (2013–2015) was included in this study. Mean cholesterol intake and the prevalence of subjects with cholesterol intake over the Intake Goal of the Dietary Reference Intakes (DRIs) for Koreans were analyzed. Intakes of cholesterol by food groups or each food were calculated to find out the major food sources for cholesterol intake in Koreans. RESULTS: The mean dietary cholesterol intake was 261.3 mg, which was higher in men (303.5 mg) compared to women (219.1 mg). Dietary cholesterol intake and the prevalence of subjects with cholesterol intake over the Intake Goal of DRIs were the highest in the 19-29 year old group. The eggs was the first major food group source for cholesterol intake in all age groups. Major food sources for cholesterol intake among Korean were egg, chicken, pork, squid and beef, which contributed 66.9% to total cholesterol intake. CONCLUSIONS: Although the mean dietary cholesterol intake was under 300 mg, the prevalence of subjects with cholesterol intake over the Intake Goal of DRIs was about 30% in adults. Because both the mean intake and the prevalence of subjects with cholesterol intake over the Intake Goal of DRIs were higher in young adult groups, the dietary cholesterol intake was expected to be increased.

Development of a Dietary Fiber Composition Table and Intakes of Dietary Fiber in Korea National Health and Nutrition Examination Survey (KNHANES) / 대한지역사회영양학회지

OBJECTIVES: The purpose of the study was to develop a dietary fiber composition table (DFCT) and to assess dietary fiber intakes in Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: The DFCT was developed by compiling the food composition tables published by the agencies of Korea, United States, or Japan. When there was no available data from the same species or status (dried, boiled, etc.) of food, the values were imputed by estimating from the same species with different status or substituting familiar species in biosystematic grouping. Using KNHANES VI-2 (2014) microdata and DFCT, intake of dietary fiber of Koreans was estimated. RESULTS: Among the 5,126 food items of DFCT, the proportion of items of which dietary fiber contents were taken from the analytical values of the same foods was 40.9%. The data from the domestic food composition tables was 37.5%, and the data from the foreign tables was 49.6%. The rest was assumed as zero, or estimated with recipe database and nutrition labeling. Mean daily intake of dietary fiber was 23.2 g, and mean intake per 1,000 kcal was 10.7 g in men and 12.6 g in women. The mean percentage of dietary fiber intake compared to adequate intake was higher than 100%. The major food groups contributing to dietary fiber intakes were vegetables and cereals, and the percent contribution were 32.9% and 23.0% of total dietary fiber intakes, respectively. CONCLUSIONS: This DFCT could serve as a useful database for assessing dietary fiber intakes and for investigating the association between dietary fiber intakes and non-communicable diseases.

Dietary intake of fats and fatty acids in the Korean population: Korea National Health and Nutrition Examination Survey, 2013

BACKGROUND/OBJECTIVES: The aim of this study was to estimate average total fat and fatty acid intakes as well as identify major food sources using data from the Korea National Health and Nutrition Examination Survey (KNHANES) VI-1 (2013). SUBJECTS/METHODS: Total fat and fatty acid intakes were estimated using 24-hour dietary recall data on 7,048 participants aged > or = 3 years from the KNHANES VI-1 (2013). Data included total fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), n-3 fatty acid (n-3 FA), and n-6 fatty acid (n-6 FA) levels. Population means and standard errors of the mean were weighted in order to produce national estimates and separated based on sex, age, income, as well as residential region. Major food sources of fat, SFA, MUFA, PUFA, n-3 FA, and n-6 FA were identified based on mean consumption amounts of fat and fatty acids in each food. RESULTS: The mean intake of total fat was 48.0 g while mean intakes of SFA, MUFA, PUFA, n-3 FA, and n-6 FA were 14.4 g, 15.3 g, 11.6 g, 1.6 g, and 10.1 g, respectively. Intakes of MUFA and SFA were each higher than that of PUFA in all age groups. Pork was the major source of total fat, SFA, and MUFA, and soybean oil was the major source of PUFA. Milk and pork were major sources of SFA in subjects aged 3-11 years and > or = 12 years, respectively. Perilla seed oil and soybean oil were main sources of n-3 FA in subjects aged > or = 50 years and aged < 50 years, respectively. CONCLUSIONS: Estimation of mean fatty acid intakes of this study using nationally represented samples of the Korean population could be useful for developing and evaluating national nutritional policies.

Development of a Food Frequency Questionnaire for the Korea National Health and Nutrition Examination Survey: Data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV)

The objective of this study was to develop a semi-quantitative food frequency questionnaire (FFQ) for an adult population for use in the Korea National Health and Nutrition Examination Survey (KNHANES). The 24-hour recall data for 2,939 subjects aged 19 years and over from the fourth KNHANES first year (2007) were used to extract the items included in the questionnaire. The FFQ items were developed by selection of major dishes based on the cumulative contribution rate, between-person variability based on the cumulative R2 of energy and 14 nutrients (carbohydrate, protein, fat, crude fiber, calcium, phosphorous, iron, sodium, potassium, vitamin A, thiamin, riboflavin, niacin, and vitamin C) and the number of consumers of each dish. In addition, the FFQ items were revised with analysis of 24-hour recall data of the fourth KNHANES second and third year (2008, 2009). Finally, 112 items were included in the FFQ and grouped as follows: rice (5 items), noodles and dumplings (6), breads and rice cakes (8), soups and stews (12), soybeans, eggs, meat and fish (23), vegetables, seaweed and potatoes (27), milk and dairy products (4), fruits (13), beverages (5), snacks (6) and alcoholic beverages (3). The food items of FFQ accounted for an average of 87.0% of energy and 14 nutrient intakes and also accounted for 81.7% of the between-person variability. The frequency range of the FFQ items was classified into nine categories (never or seldom, once per month, 2-3 times per month, once per week, 2-4 times per week, 5-6 times per week, once per day, twice per day and three times per day) and the portion size was divided into three categories (small, medium and large). We expect that this developed dish-based FFQ could be used in assessment of long-term dietary intakes of Korean adults.

Dietary Behaviors Related to Metabolic Syndrome in Korean Adults / 대한지역사회영양학회지

This study was conducted to investigate the cross-sectional associations between dietary factors and the risk of metabolic syndrome (MetS) in 12,755 subjects (males 5,146, females 7,609) aged 19 years or above using data from the 4th (2007-2009) Korea National Health and Nutrition Examination Survey (KNHANES). The prevalence of MetS in Korean adults was 23.6% (males 26.1%, females 20.9%) with the criteria for modified National Cholesterol Education Program Adult Treatment Panel III. While males had a higher prevalence of abdominal obesity, hyperglycemia, hypertriglyceridemia, and high blood pressure than females, the prevalence of low HDL-cholesterol level was higher in females than in males. Among dietary guidelines, the response of 'yes' for asking practice of 'avoiding salty foods', and 'eating moderately and increasing physical activity for healthy weight' were significantly associated with the decreased risk of MetS in both males and in females. Especially, the risk of MetS was significantly lower in the subjects that responded the practice of all items of Korean Dietary Guidelines. Significantly negative associations with MetS were also found in the responding for practice of 'limiting consumption of alcoholic beverages' in males, and taking dietary supplements in females. Skipping breakfast was positively associated with the risk of MetS. In conclusion, dietary behaviors such as having breakfast, practice of dietary guidelines, and food consumption in moderation could modify the prevalence of MetS, and our findings could be useful for establishing guidelines for preventing MetS.

Plan and Operation of the 4th Korea National Health and Nutrition Examination Survey (KNHANES IV) / 한국역학회지

The general aim of Korea National Health and Nutrition Examination Survey (KNHANES) was to assess the health and nutritional status in the Korean population. The KNHANES began in 1998 and has been conducting as a series of surveys : 1998(1st), 2001(2nd), 2005(3rd) and 2007-2009(4th). Specific aims were, in a cross-sectional study of nationally representative samples of the noninstitutionalized civilian Korean population aged > or = 1 year (4,600 households each year), to monitor trends the prevalence, awareness, treatment and control of selected chronic diseases, monitor trends in nutritional status and risk behaviors, and analyze risk factors for chronic diseases. For these purposes, with standardized high-quality methods, extensive data on health and nutrition are collected by health interview, health examination (physical examination, clinical measurements and tests) and dietary interview. In 2007, the 4th KNHANES became a continuous annual survey by highly trained field staff. In addition, the 4th KNHANES expanded examination components (addition of oral examination, pulmonary function test and laboratory test items such as ferritin, vitamin D, insulin, manganese, and arsenic), simplified survey procedure, and strengthened quality control. Further works will be focused on the selection of new examination and interview components, planning of KNHANES follow-up survey, continuous training of field staff and quality control, and improvement of dietary survey method.

Grape extracts suppress the formation of preneoplastic foci and activity of fatty acid synthase in rat liver

This study was conducted to examine the effects of dietary grape extracts on preneoplastic foci formation in rat hepatocarcinogenesis, and related hepatic enzymes. Male Sprague-Dawley rats were fed basal diet or grape diet containing 15% concentrated grape extracts (68 bricks). The grape diet groups were divided into whole-period grape diet group (DEN-GW; grape diet group fed throughout experimental period) and postinitiation grape diet group (DEN-GP; grape diet group fed from post initiation stage) according to the starting time point of the grape diet. Hepatocarcinogenesis was induced by diethylnitrosamine (DEN; 200 mg/kg bw) and 2/3 partial hepatectomy (DEN-B; DEN-treated basal diet group, DEN-GW, and DEN-GP groups), while the control group treated with saline and sham operation (Control group). The formation of placental glutathione (GSH) S-transferase positive (GST-P(+)) foci in DEN-GW group was moderately but significantly suppressed, however, not in DEN- GP group. Thiobarbituric acid reactive substances content of DEN-GW group was significantly lower than that of DEN-B group. The activity of fatty acid synthase (FAS) in the grape diet groups was decreased about 1/2 of the DEN-B group. The content of GSH and GSH peroxidase activity were increased by carcinogen treatment, but not modulated by grape diet. The activities of GSH S-transferase, p-nitrophenol hydroxylase, and catalase were not affected by diet or treatment. Conclusively, the grape diet-induced reduction of FAS activity that was expressed highly in neoplastic tissues, might be one of the contributing mechanisms of hepatic cancer prevention.