The presence of metabolic syndrome in children and adolescents represents a high-risk state that conveys an increased risk of metabolic disease (1,2). The importance of the role of dietary patterns cannot be overemphasized because of the relation to metabolic disease. Although previous studies show that some dietary patterns are related to the risk of the metabolic syndrome (3–6), these studies focus on adults and were rarely conducted on children or adolescents in a nationally based survey. Therefore, the aim of this study was to identify dietary patterns and to examine the association between dietary patterns and the metabolic syndrome in Korean adolescents. Although studies on the Korean population may yield unique results primarily due to the ethnic homogeneity inherent to the Korean population with very little genetic diversity, the results tend to be applicable to other countries as well.
RESEARCH DESIGN AND METHODS—
The 2001 Korean National Health and Nutrition Survey, a cross-sectional and nationally representative survey, was conducted from November to December 2001. A stratified, multistage, probability sampling design was used, with selection made from sampling units. Weights indicating the probability of being sampled were assigned to each participant, which enabled the results to represent the entire Korean population.
A total of 12,441 individuals participated in the Health Interview Survey, which included a 24-h dietary intake recall. Complete data were obtained from 10,051 participants (80.8%). Of these participants, data from 1,484 adolescent subjects aged 10–19 years were examined. Among them, 1,271 subjects (655 boys and 616 girls) had laboratory tests taken. Subjects who had not fasted for at least 7 h or for whom the duration of fasting was unknown were excluded from the analysis (n = 327). The final sample consisted of 944 (501 boys and 443 girls) adolescent subjects.
For a metabolic syndrome definition, age-modified standards of the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III metabolic syndrome criteria were used (7). These criteria were modified for adolescents to include elevated blood pressure defined as systolic or diastolic blood pressure >90th percentile for age, sex, and height based on the Korean Pediatric Society, 1999 (8,9); fasting plasma glucose ≥100 mg/dl (10); triglyceride concentration ≥110 mg/dl; and HDL cholesterol concentration <40 mg/dl. Those with a waist circumference ≥90th percentile value for age and sex were classified as having abdominal obesity. Subjects who met at least three of the five criteria were classified as having a metabolic syndrome phenotype.
Dietary intake was collected by a 24-h recall. Food grouping was based on the classification of food groups used by the Korean Nutrient Database (Korean Nutrition Society, 2005). All statistical analyses were conducted using the SUDAAN release, version 9.0 (Research Triangle Institute, Research Triangle Park, NC).
RESULTS—
Patterns were labeled according to the highest consumption of food groups. The largest cluster (55.2%) had the highest consumption of rice and kimchi, fish and seaweed, and legumes and was labeled as the “Korean traditional” pattern group. Another cluster (26.1%) had the highest consumption of flour and bread, pizza and hamburgers, snacks and cereals, sugars and sweets, meats, and beverages (carbonated) and was labeled as the “Western” pattern group. The smallest cluster (18.7%) had the highest consumption of noodles and dumplings with some consumption of rice and kimchi and was labeled as the “Modified” pattern group.
In both sexes, the total energy intake and percentage of energy from protein and fat was highest in the Western group, and, conversely, the percentage of energy from carbohydrates was lowest in the Western group. In the Korean traditional group, the percentage of energy from carbohydrates was highest, and the percentage of energy from fat was lowest.
The prevalence of abdominal obesity was higher in the Western group (16.08% [95% CI 11.61–21.85]) than in the Korean traditional (9.76% [7.38–12.80]) or the modified (9.75% [5.44–16.88]) group. The highest prevalence of high triglyceride and high fasting plasma glucose was also found in the Western group. The prevalence of the metabolic syndrome was not significantly different among dietary patterns.
Table 1 shows the odds ratio (OR) for individual risk factors of the metabolic syndrome, classified by dietary patterns. After adjusting for sex and age, the ORs of the metabolic syndrome were not significantly different among dietary patterns; however, the OR of abdominal obesity was significantly higher in the Western group.
CONCLUSIONS—
Using the food groupings, three distinct dietary patterns—Korean traditional, Western, and modified—were identified in Korean adolescents. Among them, the Korean traditional group was the most prevalent (55.2%), followed by the Western (26.1%) and the modified (18.7%) groups.
With increased economic growth, the percentage of energy from fat in the diet has rapidly increased in Korea (11), which is related to the introduction and widespread availability of fast food restaurants. In the Western group, the energy intake from fat was much higher compared with the Korean traditional and modified groups. Although there was no significant difference in the OR for the metabolic syndrome after adjusting for age and sex, the OR for abdominal obesity was the highest in the Western group. This result could be related to the fact that abdominal obesity is an earlier-expressed phenotype of the metabolic syndrome in adolescents.
This study has some limitations, mainly due to the cross-sectional design, which makes it difficult to determine causality. Even after some adjustments were made, there still might be a potential for residual confounding. Although the 24-h recall method is useful to estimate population means, the values from the single recalls cannot be corrected for intra-individual daily variation in consumption. In addition, the lack of information regarding saturated fatty acids is problematic.
In conclusion, the Korean traditional is the most prevalent dietary pattern in Korean adolescents. The OR for abdominal obesity in the Western group was significantly higher than in the Korean traditional or modified groups, although there was no difference in the OR for the metabolic syndrome among the different dietary patterns.
ORs for the metabolic syndrome and individual metabolic risk factors classified by dietary patterns among Korean adults from the Korean National Health and Nutrition Examination Survey, 2001
| . | Korean traditional pattern . | Modified pattern . | Western pattern . |
|---|---|---|---|
| n | 539 | 182 | 223 |
| Unadjusted | |||
| Metabolic syndrome | 1 | 0.839 (0.472–1.493) | 0.971 (0.547–1.727) |
| Abdominal obesity | 1 | 0.998 (0.470–2.123) | 1.807 (1.096–2.977) |
| Elevated blood pressure | 1 | 0.873 (0.545–1.397) | 0.732 (0.458–1.169) |
| Fasting plasma glucose ≥100 mg/dl | 1 | 0.823 (0.535–1.267) | 1.029 (0.728–1.456) |
| Triglyceride ≥110 mg/dl | 1 | 1.133 (0.691–1.858) | 1.410 (0.963–2.066) |
| HDL cholesterol ≤40 mg/dl | 1 | 1.137 (0.731–1.769) | 0.848 (0.528–1.364) |
| Adjusted for age and sex | |||
| Metabolic syndrome | 1 | 0.868 (0.482–1.561) | 1.010 (0.566–1.803) |
| Abdominal obesity | 1 | 1.000 (0.481–2.080) | 1.806 (1.093–2.984) |
| Elevated blood pressure | 1 | 0.870 (0.527–1.438) | 0.752 (0.469–1.207) |
| Fasting plasma glucose ≥100 mg/dl | 1 | 0.902 (0.577–1.408) | 1.067 (0.756–1.507) |
| Triglyceride ≥110 mg/dl | 1 | 1.173 (0.712–1.933) | 1.427 (0.977–2.083) |
| HDL cholesterol ≤40 mg/dl | 1 | 1.092 (0.699–1.707) | 0.867 (0.534–1.408) |
| . | Korean traditional pattern . | Modified pattern . | Western pattern . |
|---|---|---|---|
| n | 539 | 182 | 223 |
| Unadjusted | |||
| Metabolic syndrome | 1 | 0.839 (0.472–1.493) | 0.971 (0.547–1.727) |
| Abdominal obesity | 1 | 0.998 (0.470–2.123) | 1.807 (1.096–2.977) |
| Elevated blood pressure | 1 | 0.873 (0.545–1.397) | 0.732 (0.458–1.169) |
| Fasting plasma glucose ≥100 mg/dl | 1 | 0.823 (0.535–1.267) | 1.029 (0.728–1.456) |
| Triglyceride ≥110 mg/dl | 1 | 1.133 (0.691–1.858) | 1.410 (0.963–2.066) |
| HDL cholesterol ≤40 mg/dl | 1 | 1.137 (0.731–1.769) | 0.848 (0.528–1.364) |
| Adjusted for age and sex | |||
| Metabolic syndrome | 1 | 0.868 (0.482–1.561) | 1.010 (0.566–1.803) |
| Abdominal obesity | 1 | 1.000 (0.481–2.080) | 1.806 (1.093–2.984) |
| Elevated blood pressure | 1 | 0.870 (0.527–1.438) | 0.752 (0.469–1.207) |
| Fasting plasma glucose ≥100 mg/dl | 1 | 0.902 (0.577–1.408) | 1.067 (0.756–1.507) |
| Triglyceride ≥110 mg/dl | 1 | 1.173 (0.712–1.933) | 1.427 (0.977–2.083) |
| HDL cholesterol ≤40 mg/dl | 1 | 1.092 (0.699–1.707) | 0.867 (0.534–1.408) |
Data are ORs or OR (95% CI).
Article Information
This study was supported by a grant of the Seoul Research and Business Development Program, Republic of Korea (10526).
References
Published ahead of print at http://care.diabetesjournals.org on 6 April 2007. DOI: 10.2337/dc06-2591.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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