Comparison of total energy intakes estimated by 24-hour diet recall with total energy expenditure measured by the doubly labeled water method in adults.

BACKGROUND/OBJECTIVES: The doubly labeled water (DLW) method is the gold standard for estimating total energy expenditure (TEE) and is also useful for verifying the validities of dietary evaluation tools. In this study, we compared the accuracy of total energy intakes (TEI) estimated by the 24-h diet recall method with TEE obtained using the doubly labeled water method. SUBJECTS/METHODS: This study involved 71 subjects aged 20-49 yrs. Over a 14-day period, three 24-h diet recalls per subject (2 weekdays and 1 weekend day) were used to estimate energy intakes, while TEE was measured using the DLW method. The paired t-test was used to determine the significance of differences between TEI and TEE results, and the accuracy of the 24-h recall method was determined by accuracy predictions percentage, root mean square error, and bias. RESULTS: Average study subject age was 33.4 ± 8.6 yrs. The association between TEI and TEE was positive and significant (r = 0.463, P < 0.001), and the difference between TEI (2,084.3 ± 684.2 kcal/day) and TEE (2,401.7 ± 480.3 kcal/day) was also significant (P < 0.001). In all study subjects, mean TEI was 12.0% (307.5 ± 629.3 kcal/day) less than mean TEE, and 12.2% (349.4 ± 632.5 kcal/day) less in men and 11.8% (266.7 ± 632.5 kcal/day) less in women. Rates of TEI underprediction for all study subjects, men, and women, were 60.5%, 51.4%, and 66.7%, respectively. CONCLUSIONS: This study shows that 24-h diet recall underreports energy intakes. More research is needed to corroborate our findings and evaluate the accuracy of 24-h recall with respect to additional demographics.

Trends in the prevalence and management of major metabolic risk factors for chronic disease over 20 years: findings from the 1998-2018 Korea National Health and Nutrition Examination Survey.

OBJECTIVES: We aimed to explore trends in the prevalence and management of obesity, hypertension, diabetes, and hypercholesterolemia in Korean adults from 1998 to 2018 using data from the Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: The study participants included 79,753 individuals aged ≥ 30 years who had participated in the health examination and health interview of the first (1998) to the seventh (2016-2018) KNHANES. The prevalence and management as well as annual percent change (APC) in chronic diseases were analyzed using SAS and the Joinpoint software program. RESULTS: The prevalence of obesity in men significantly increased from 26.8% in 1998 to 44.7% in 2018 (APC= 1.9, p< 0.001), whereas that in women decreased slightly from 30.5% in 1998 to 28.3% in 2018 (APC= -0.5, p< 0.001). The prevalence of hypertension in men was 33.2% in 2018, with no significant change, whereas that in women slightly decreased to 23.1% in 2018 (APC= -0.9, p< 0.001). The prevalence of diabetes in men increased slightly from 10.5% in 2005 to 12.9% in 2018 (APC= 1.6, p< 0.001), whereas that in women remained at approximately 8%, with no significant change. The prevalence of hypercholesterolemia in both men and women increased 3-fold in 2018 (20.9% in men [APC = 8.2, p < 0.001] and 21.4% in women [APC= 7.1, p< 0.001]) compared to that in 2005. The awareness rate, treatment rate, and control rate of hypertension and hypercholesterolemia increased 2-3 fold. Regarding diabetes, the treatment rate increased, but the control rate did not change. CONCLUSIONS: Over the past 20 years, the prevalence of obesity (in men), diabetes, and hypercholesterolemia has increased and management indicators, such as the awareness rate, treatment rate, and control rate of chronic diseases, have improved continuously.

Baseline Assessment of 25-Hydroxyvitamin D Reference Material and Proficiency Testing/External Quality Assurance Material Commutability: A Vitamin D Standardization Program Study.

The Vitamin D Standardization Program (VDSP) coordinated a study in 2012 to assess the commutability of reference materials and proficiency testing/external quality assurance materials for total 25-hydroxyvitamin D [25(OH)D] in human serum, the primary indicator of vitamin D status. A set of 50 single-donor serum samples as well as 17 reference and proficiency testing/external quality assessment materials were analyzed by participating laboratories that used either immunoassay or LC-MS methods for total 25(OH)D. The commutability test materials included National Institute of Standards and Technology Standard Reference Material 972a Vitamin D Metabolites in Human Serum as well as materials from the College of American Pathologists and the Vitamin D External Quality Assessment Scheme. Study protocols and data analysis procedures were in accordance with Clinical and Laboratory Standards Institute guidelines. The majority of the test materials were found to be commutable with the methods used in this commutability study. These results provide guidance for laboratories needing to choose appropriate reference materials and select proficiency or external quality assessment programs and will serve as a foundation for additional VDSP studies.

Baseline Assessment of 25-Hydroxyvitamin D Assay Performance: A Vitamin D Standardization Program (VDSP) Interlaboratory Comparison Study.

The Vitamin D Standardization Program (VDSP) coordinated an interlaboratory study to assess the comparability of measurements of total 25-hydroxyvitamin D [25(OH)D] in human serum, which is the primary marker of vitamin D status. A set of 50 individual donor samples were analyzed by 15 different laboratories representing national nutrition surveys, assay manufacturers, and clinical and/or research laboratories to provide results for total 25(OH)D using both immunoassays (IAs) and LC tandem MS (MS/MS). The results were evaluated relative to bias compared with the target values assigned based on a combination of measurements at Ghent University (Belgium) and the U.S. National Institute of Standards and Technology using reference measurement procedures for the determination of 25(OH)D2 and 25(OH)D3. CV and mean bias for each laboratory and assay platform were assessed and compared with previously established VDSP performance criteria, namely CV ≤ 10% and mean bias ≤ 5%. Nearly all LC-MS/MS results achieved VDSP criteria, whereas only 50% of IAs met the criterion for a ≤10% CV and only three of eight IAs achieved the ≤5% bias. These results establish a benchmark for the evaluation of 25(OH)D assay performance and standardization activities in the future.

Household food insecurity and dietary intake in Korea: results from the 2012 Korea National Health and Nutrition Examination Survey.

OBJECTIVE: To examine the prevalence of household food insecurity and compare dietary intake by food security status in a representative Korean population. DESIGN: Cross-sectional. Food security status of households was classified using an eighteen-item food security questionnaire. The nutrition survey comprised questions on dietary habits, a 24 h dietary recall and a semi-quantitative FFQ. SETTING: The 2012 Korea National Health and Nutrition Examination Survey. SUBJECTS: A total of 3007 households completed the food security questionnaire. Family members within each household aged ≥1 year (n 7118) participated in the nutrition survey. RESULTS: Results from the 2012 survey indicated that 88.7% of Korean households showed food security. The remaining 11.3% (9.3% for food insecurity without hunger and 2.0% for food insecurity with hunger) were in food-insecure households. The prevalence of household food insecurity was 13.2% in households with children and 10.3% in households without children. Mean daily intakes of energy, fat and carbohydrates were not significantly different between food-secure and food-insecure adults. In contrast, mean daily intakes of protein, crude fibre, vitamins and minerals as well as weekly consumption frequencies of vegetables, seaweeds, fruits, fruit juice, nuts, and milk and milk products were significantly lower in food-insecure adults compared with food-secure adults. CONCLUSIONS: The study demonstrated that food insecurity is associated with reduced intakes of healthy foods and nutrients essential for health and growth in a representative Korean population.

Preservation of a traditional Korean dietary pattern and emergence of a fruit and dairy dietary pattern among adults in South Korea: secular transitions in dietary patterns of a prospective study from 1998 to 2010.

Transitions in nutrition patterns tend to emerge through industrialization and economic development. We hypothesized that the dietary patterns among South Korean adults who were 20 years or older have changed significantly from 1998 to 2010. Herein, a repeated cross-sectional analysis of data was followed for 140601 adults. We noted changes in consumption, after adjusting for age, sex, body mass index, and exercise, and tested the trends across the study period. Factor and cluster analyses were used to derive dietary patterns. A decrease in traditional Korean food consumption, including cereals, vegetables (252-176 g), and Kimchi (127-82 g), occurred, whereas fruit (172-252 g), egg, and fried food intakes increased (P < .05). Total daily energy intake declined steadily from 1931 in 1998 to 1691 kcal in 2010. Carbohydrate intakes were unchanged over the study period; however, fat-derived energy intake increased slightly from 19.7% to 20.0% (P < .05). Our factor and cluster analyses identified 3 dietary patterns: "Korean" diet (rice, vegetables, and Kimchi), "Western" diet (soda, eggs, and oil), and "New" diet (low sugar and high fruit and dairy product intakes). Compared to 1998, approximately 40% of participants still followed a Korean diet in 2010. Interestingly, the popularity of the Western diet fell by approximately 20%, whereas the new diet pattern increased 2-fold over the study period. Overall, these data show secular trends in dietary patterns that included a preservation of the traditional Korean diet and the emergence of a new diet pattern, and it demonstrated a unique transition in food and nutrient intakes in Korea.

Dietary assessment methods in epidemiologic studies.

Diet is a major lifestyle-related risk factor of various chronic diseases. Dietary intake can be assessed by subjective report and objective observation. Subjective assessment is possible using open-ended surveys such as dietary recalls or records, or using closed-ended surveys including food frequency questionnaires. Each method has inherent strengths and limitations. Continued efforts to improve the accuracy of dietary intake assessment and enhance its feasibility in epidemiological studies have been made. This article reviews common dietary assessment methods and their feasibility in epidemiological studies.

Data resource profile: the Korea National Health and Nutrition Examination Survey (KNHANES).

The Korea National Health and Nutrition Examination Survey (KNHANES) is a national surveillance system that has been assessing the health and nutritional status of Koreans since 1998. Based on the National Health Promotion Act, the surveys have been conducted by the Korea Centers for Disease Control and Prevention (KCDC). This nationally representative cross-sectional survey includes approximately 10 000 individuals each year as a survey sample and collects information on socioeconomic status, health-related behaviours, quality of life, healthcare utilization, anthropometric measures, biochemical and clinical profiles for non-communicable diseases and dietary intakes with three component surveys: health interview, health examination and nutrition survey. The health interview and health examination are conducted by trained staff members, including physicians, medical technicians and health interviewers, at a mobile examination centre, and dieticians' visits to the homes of the study participants are followed up. KNHANES provides statistics for health-related policies in Korea, which also serve as the research infrastructure for studies on risk factors and diseases by supporting over 500 publications. KCDC has also supported researchers in Korea by providing annual workshops for data users. KCDC has published the Korea Health Statistics each year, and microdata are publicly available through the KNHANES website (http://knhanes.cdc.go.kr).