Changes in food and nutrient intakes in Korean adults before and during the COVID-19 pandemic: data from the 2011-2020 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: This study was to examine the changes in dietary habits and food and nutrient intakes between before (2019) and during (2020) the coronavirus disease 2019 (COVID-19) pandemic from the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: A total of 54,995 participants aged ≥19 years who participated in the 2011-2020 KNHANES were included. The 10-year trend (2011-2020) and differences between 2019 and 2020 for dietary habits and food and nutrient intakes were estimated using SAS. RESULTS: In the past 10 years (2011-2020), the dietary habits (increase in skipping meals and eating out), food intake (increase in meats and decrease in fruits and vegetables), and nutrient intake (increase in fat and decrease in sodium) in adults have changed. When comparing between 2019 and 2020, there were 4.6%p decrease in the eating out more than once a day. On the other hand, there were no significant differences in the intakes of food, energy and most of nutrients between 2019 and 2020, except for the proportion of energy intake from fat (1.0%p increase) and carbohydrate (1.0%p decrease). CONCLUSIONS: Although a change in dietary habits from before to during the COVID-19 pandemic was observed, food and nutrient intakes have not deteriorated markedly and appear similar to the trends in the past 10 years. Throughout the COVID-19 pandemic, it is necessary to monitor the effects of changes in dietary habits on health as well as food and nutrient intakes.

Development of the Korean Healthy Eating Index for adults, based on the Korea National Health and Nutrition Examination Survey.

BACKGROUND/OBJECTIVES: The objective of this study was to describe the development process of the Korean Healthy Eating Index (KHEI) based on the Korea National Health and Nutrition Examination Survey (KNHANES). SUBJECTS/METHODS: The components of KHEI were selected based on Dietary Guidelines for Koreans, domestic and overseas dietary quality indices, and results of the analysis of association with chronic diseases. The standards for scoring of KHEI were selected based on the 2015 Dietary Reference Intakes for Koreans (KDRI). The KHEI scores of Korean adults were calculated using a 1-day 24-h recall data in the 2013-2015 KNHANES. RESULTS: The KHEI included eight adequacy components evaluating the proper intake of recommended foods such as fruit, vegetable, and milk and three moderation components evaluating the consumption of food that limit intake such as sodium and saturated fatty acid. In addition, three balance components assessing the balance of energy intake were included. The KHEI score was defined to range from the minimum of 0 point to the maximum of 100 points. Among Korean adults, the total KHEI score was 63.2 out of 100. Gender and age differences were found in the average of total KHEI scores. Women showed higher score than men (61.7 in men and 64.7 in women, respectively). By age group, 20s and 30s showed the lowest scores with 57.4 and 61.1 respectively, and the scores increased with age by peaking at 67.8 in ages 60-69 and slowed down again in ages 70 or over. CONCLUSIONS: The KHEI can be useful for establishing and assessing national nutritional policies and in epidemiological studies to assess the relationship between overall dietary quality and chronic diseases. KHEI will need to be continuously updated to reflect changes in dietary guidelines and the KDRI.

Gender and tobacco epidemic in South Korea: implications from age-period-cohort analysis and the DPSEEA framework.

OBJECTIVES: To understand a 20-year trend of gender-specific smoking prevalence among adults in South Korea. DESIGN: Age-period-cohort analysis using the intrinsic estimator method was applied to examine the separate contribution of age, period and cohort effect on smoking prevalence. The Driving Force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework was used to explain the observed smoking trends by mapping potential determinants and to address policy implications. SETTING: General adult population in South Korea. PARTICIPANTS: 34 828 men and 43 632 women who aged 19-78 years, were not currently pregnant and were without a prior diagnosis of cardiovascular disease or cancer. OUTCOME MEASURES: Gender-specific current smoking prevalence using the 1998-2017 Korea National Health and Nutrition Examination Survey. RESULTS: Our results showed gender-specific age and birth cohort effects. More specifically, the smoking prevalence peaked at their mid-20s (prevalence rate ratio (PRR): 1.54, 95% CI: 1.49 to 1.59) and cohort born in 1959-1963 (PRR: 1.63, 95% CI: 1.57 to 1.70) and then decreased in men. On the other hand, in women, the smoking prevalence consistently increased until their mid-40s (PRR: 1.53, 95% CI: 1.27 to 1.84) and in recent birth cohort groups (PRR in 1994-1998 cohort: 1.55, 95% CI: 1.13 to 2.13). The period effects declined from 1998-2002 to 2003-2007, following increasing fluctuations in both genders. The smoking-DPSEEA framework showed the absence of policy actions to target female smokers and emphasised a proactive approach that tackles the upstream causes for smoking in women. CONCLUSIONS: Men and women are clearly in different phases of the smoking epidemic in Korean population, and gender-tailored policies should be implemented.

The Korea National Health and Nutrition Examination Survey data linked Cause of Death data.

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national health survey that is conducted annually to assess the health and and health-related behaviors of Korean population. To utilize KNHANES data to studies of mortality risk factors, the Korea Disease Control and Prevention Agency (KDCA) constructed a database linking KNHANES data to cause-of-death statistics in Statistics Korea, made available to researchers since 2020. The KNHANES data were linked to the Cause of Death Statistics based on resident registration numbers for subjects aged 19 years or older who agreed to link the data. The linkage rate between 2007-2015 National Health and Nutrition Examination Survey and 2007-2019 Cause of Death Statistics was 97.1%. In the linked dataset, the total death rate was 6.6%, of which neoplasms accounted for the highest death rate (32.1%), followed by circulatory system disease (22.7%) and respiratory system disease (11.5%). The linked dataset was made available through the Research Data Center of the KDCA after a review of the research proposal, and will be made available after periodical updates.

Effects of exposure to ambient air pollution on pulmonary function impairment in Korea: the 2007-2017 Korea National Health and Nutritional Examination Survey.

OBJECTIVES: This study aimed to investigate the association between pulmonary function and air pollution using 2007-2017 data from the Korea National Health and Nutrition Examination Survey, a nationwide cross-sectional representative survey. METHODS: A total of 27,378 participants that had sampling weights from a complex sample survey were included in this study. Using the data for forced expiratory volume in 1 second and forced vital capacity, the participants with pulmonary function impairment were classified according to the criteria of restrictive lung disease and chronic obstructive pulmonary disease (COPD). Exposure to ambient air pollution was estimated using the Community Multiscale Air Quality model. Multivariate linear and logistic regression analyses with complex samples were used to determine the associations between pulmonary function and air pollution after adjusting for covariates. RESULTS: In total, 13.2% of the participants aged >40 years had COPD, and 10.7% were classified as being in the restrictive lung disease group. According to the multivariate logistic regression model, the odds ratios for the fourth quartiles of particulate matter less than 10 µm in diameter (PM10), particulate matter less than 2.5 µm in diameter (PM2.5) and carbon monoxide (CO) with a 2-year lag period were 1.203 (95% confidence interval [CI], 1.036 to 1.396), 1.283 (95% CI, 1.101 to1.495), and 1.292 (95% CI, 1.110 to 1.504), respectively, using the restrictive lung disease group as an event after adjusting for covariates in the complex sample. CONCLUSIONS: Long-term exposure to PM10, PM2.5, and CO was significantly associated with pulmonary function, especially restrictive lung disease.

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

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.

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.

Establishment of the Korea National Health and Nutrition Examination Survey air pollution study dataset for the researchers on the health impact of ambient air pollution.

To provide a nationwide representative dataset for the study on health impact of air pollution, we combined the data from the Korea National Health and Nutrition Examination Survey with the daily air quality and weather data by matching the date of examination and the residential address of the participants. The database of meteorological factors and air quality as sources of exposure data were estimated using the Community Multiscale Air Quality model. The linkage dataset was merged by three ways; administrative district, si-gun-gu (city, county, and district), and geocode (in latitude and longitude coordinate units) based on the participants' residential address, respectively. During the study period, the exposure dataset of 85,018 individuals (38,306 men and 46,712 women) whose examination dates were recorded were obtained. According to the definition of exposure period, the dataset was combined with the data on short-term, mid-term, and long-term exposure to air pollutants and the meteorological indices. Calculation of the daily merged dataset's average air pollution linked by si-gun-gu and geocode units showed similar results. This study generated a daily average of meteorological indices and air pollution exposure dataset for all regions including rural and remote areas in Korea for 11 years. It is expected to provide a platform for the researchers studying the health impact of air pollution and climate change on the representative population and area, which may facilitate the establishment of local health care plans by understanding the residents' health status at the local as well as national level.

Beverage consumption among Korean adolescents: data from 2016 Korea Youth Risk Behavior Survey.

BACKGROUND/OBJECTIVES: Association between the consumption of sugar-sweetened beverages (SSBs) and obesity is universally a controversial issue. This study was undertaken to examine the beverage consumption pattern of Korean adolescents. SUBJECTS/METHODS: Data was collected from the 2016 Korea Youth Risk Behavior Survey involving 65,528 adolescent respondents. A list of the most frequently consumed beverages was analyzed, and the consumption frequency of carbonated beverages, SSBs, and energy drinks during the past seven-days was assessed. The main reasons for the adolescents to consume the beverages were also determined. RESULTS: The beverage preference of adolescents were carbonated beverages (31.0%), 'fruit and vegetable beverages (17.7%)', 'milk (13.6%)', and 'coffee (12.7%)'. Carbonated beverages and SSBs were consumed more than three times a week by 27.1% and 41.1% of the respondents, respectively. About 86.2% of adolescents did not take of any energy drinks during the last seven-days. Taste was the most common reason that adolescents considered when choosing a drink. Carbonated beverages consumed more frequently by boys than girls, and high school students drank coffee more frequently than middle school students. CONCLUSIONS: Boys had a higher preference for unhealthy beverages than girls, whereas consumption of high-caffeine drinks was greater amongst high-school students than middle school students.

The 2017 Korean National Growth Charts for children and adolescents: development, improvement, and prospects.

Growth charts are curves or tables that facilitate the visualization of anthropometric parameters, and are widely used as an important indicator when evaluating the growth status of children and adolescents. The latest version of the Korean National Growth Charts released in 2007 has raised concerns regarding the inclusion of data from both breastfed and formula-fed infants, higher body mass index (BMI) values in boys, and smaller 3rd percentile values in height-for-age charts. Thus, new growth charts have been developed to improve the previous version. The 2006 World Health Organization Child Growth Standards, regarded as the standard for breastfed infants and children, were introduced for children aged 0-35 months. For children and adolescents aged 3-18 years, these new growth charts include height-for-age, weight-for-age, BMI-for-age, weight-for-height, and head circumference-for-age charts, and were developed using data obtained in 1997 and 2005. Data sets and exclusion criteria were applied differently for the development of the different growth charts. BMI-for-age charts were adjusted to decrease the 95th percentile values of BMI. Criteria for obesity were simplified and defined as a BMI of ≥95th percentile for age and sex. The 3rd percentile values for height-for-age charts were also increased. Additional percentile lines (1st and 99th) and growth charts with standard deviation lines were introduced. 2017 Korean National Growth Charts are recommended for the evaluation of body size and growth of Korean children and adolescents for use in clinics and the public health sector in Korea.

Trends in energy intake among Korean adults, 1998-2015: Results from the Korea National Health and Nutrition Examination Survey.

BACKGROUND/OBJECTIVES: Assessing changes in energy intake and dietary sources is important to understand trends in the prevalence of obesity. Thus, we examined trends in energy intake and its nutrient and food sources in Korean adults from 1998 through 2015. SUBJECTS/METHODS: This study included 70,769 subjects aged ≥ 19 years who completed a nutrition survey. Subject data were obtained from the 1998, 2001, 2005, 2007-2009, 2010-2012, and 2013-2015 Korea National Health and Nutrition Examination Surveys. Dietary intake was assessed by a 1-day 24-hour recall method. RESULTS: In men, the daily energy intake significantly increased from 2,196 kcal in 1998 to 2,489 kcal in 2013-2015 (P for trend < 0.0001). However, the daily energy intake among women did not change significantly over the same period (P for trend = 0.5772). The percentages of energy intake from animal foods (e.g., meat and milk) and beverages increased during the study period in both men and women. However, the percentage of energy intake from plant foods decreased due to a marked decrease in the intake of white rice. Changes in food sources of energy intake led to changes in the nutrient sources of energy intake; for example, the increase of energy intake from fat and decrease of energy intake from carbohydrate. CONCLUSIONS: This study suggests that since 1998, energy intake has increased among Korean adult men, but not among women. However, the composition of food and nutrient sources of energy intake has changed in both men and women. Energy intake and its nutrient and food sources should continue to be monitored regularly in the Korean adult population.

Relation of serum 25-hydroxyvitamin D status with skeletal muscle mass by sex and age group among Korean adults.

The objective of this study was to examine whether high serum 25-hydroxyvitamin D (25(OH)D) concentration was associated with high skeletal muscle mass, taking into account the effects of sex and age among the participants of the Korea National Health and Nutrition Examination Survey (KNHANES) aged 40 years or older. This was a cross-sectional study using data from the 2009 to 2010 KNHANES; a total of 8406 subjects (3671 men and 4735 women) were included. The appendicular skeletal muscle mass index (ASMMI, kg/m2) was estimated to measure the skeletal muscle mass. Hypovitaminosis was classified when the level of serum 25(OH)D was <20 ng/ml. The general linear model adjusted for confounding factors was used to determine differences in means of ASMMI by 25(OH)D status. The mean values of ASMMI were higher for men when compared with women. Women had a greater proportion of hypovitaminosis (71·1%) compared with men (53·2%). After adjusting for multiple factors, men were seen to have significant differences in ASMMI based on 25(OH)D status regardless of age, showing a lower mean value of ASSMI in those with hypovitaminosis. However, there was no difference in ASMMI by 25(OH)D status among women in both younger and older age groups. In conclusion, we found that there might be a positive relationship between 25(OH)D and skeletal muscle mass in men, indicating that interventions to improve 25(OH)D levels that are aimed at increasing muscle mass could be beneficial for men with more rapid decreased rate of skeletal muscle mass.