Obesity and the metabolic syndrome in Korean adolescents

Appraisal of Clinical Care Practices for Child Obesity Treatment. Part II: Comorbidities

The objective of this technical report is to provide clinicians with actionable evidence-based information upon which to make treatment decisions. In addition, this report will provide an evidence base on which to inform clinical practice guidelines for the management and treatment of overweight and obesity in children and adolescents. To this end, the goal of this report was to identify all relevant studies to answer 2 overarching key questions: (KQ1) "What are effective clinically based treatments for obesity?" and (KQ2) "What is the risk of comorbidities among children with obesity?" See Appendix 1 for the conceptual framework and a priori Key Questions.

Is high waist circumference and body weight associated with high blood pressure in Iranian primary school children?

INTRODUCTION AND OBJECTIVES

The prevalence of overweight, abdominal obesity and hypertension among children has increased worldwide including Iran over several decades. We carried out a study to provide current estimates of the prevalence and trends of hypertension, overweight and obesity along with the relationship between weight status and hypertension in Iranian school-children.

METHOD

This study was carried out among 1184 fifth-grade students, whose ages ranged from 11 to 14 years. Body weight, body mass index (BMI), height and waist circumference (WC), systolic (SBP) and diastolic blood pressure (DBP) were measured.

RESULTS

22.04 and 5.32 % of students were overweight and obese, respectively. The prevalence of overweight and obesity was significantly higher among girls than boys (all p = 0.02), whereas the prevalence of hypertension was significantly higher in boys than girls (p = 0.001). Although 27 % of boys and 24.32 % of girls had abdominal obesity, no significant associations were reported between abdominal obesity and sex (p = 0.12). The prevalence of hypertension in children with normal weight, overweight and obesity, was 3, 9.7 and 17.8 %, respectively (p < 0.01). We have obtained that the mean values of weight and WC were significantly higher in boys than girls. Based on linear regression, every 1 cm increase in abdominal circumference leads to an estimated DBP and SBP increase of 0.173 and 0.164 mmHg, respectively (p < 0.05).

CONCLUSIONS

This study showed a high prevalence of hypertension and obesity in a school-based population in Tehran, Iran, in which the prevalence of hypertension was significantly and positively correlated with weight and WC.

Epidemiology of Childhood Obesity in Korea

Over the past several decades, the prevalence of obesity has increased dramatically worldwide and is increasing not only in developed countries, but also in developing countries. This increase may lead to an increase in the incidence of chronic diseases throughout the lifespan. In Korean children and adolescents, the prevalence of obesity increased from 6.8% in 1998 to 10.0% in 2013. Obesity is a state that more commonly influences children and adolescents of lower socioeconomic status (SES) than those with a higher SES. However, the prevalence of metabolic syndrome in a nationally representative sample of Korean adolescents decreased from 1998 to 2012. According to the Diabetes Fact Sheet of the Korean Diabetes Association, the prevalence of type 2 diabetes among children aged 18 years or younger was 153.5 per 100,000 in 2006 and 205.0 per 100,000 in 2013. Obesity is a complex disease influenced by many interacting factors, such as adipocytokines, lipopolysaccharide-binding protein, adenovirus 36 infection, birth weight, lifestyle, and endocrine-disrupting chemicals. Obesity in youth can adversely impact practically every organ system and lead to serious consequences, such as metabolic, gastrointestinal, pulmonary, cardiovascular, and psychosocial complications. Therefore, coordinated efforts by governments, organizations, communities, and individuals are needed to prevent and treat childhood obesity. In particular, a long-term policy to improve the social environment will also be necessary.

Prevalence of high blood pressure in 122,053 adolescents: a systematic review and meta-regression

Several studies have reported high prevalence of risk factors for cardiovascular disease in adolescents. To perform: i) systematically review the literature on the prevalence of high blood pressure (HBP) in adolescents; ii) analyze the possible methodological factors associated with HBP; and iii) compare the prevalence between developed and developing countries. We revised 10 electronic databases up to August 11, 2013. Only original articles using international diagnosis of HBP were considered. The pooled prevalence's of HBP were estimated by random effects. Meta-regression analysis was used to identify the sources of heterogeneity across studies. Fifty-five studies met the inclusion criteria and total of 122,053 adolescents included. The pooled-prevalence of HBP was 11.2%, 13% for boys, and 9.6% for girls (P < 0.01). Method of measurement of BP and year in which the survey was conducted were associated with heterogeneity in the estimates of HBP among boys. The data indicate that HBP is higher among boys than girls, and that the method of measurement plays an important role in the overall heterogeneity of HBP value distributions, particularly in boys.

Overview of noncommunicable diseases in Korean children and adolescents: focus on obesity and its effect on metabolic syndrome

Obesity during childhood is a dominant risk factor for noncommunicable diseases (NCDs), and is itself considered a disease that needs to be treated. Recently, the growth in childhood obesity in Korea has become stagnant; however, two in every ten children are still overweight. In addition, 60% or more of overweight children have at least one metabolic syndrome risk factor. Thus, childhood obesity should be controlled through lifestyle modification. This paper reviews studies of the modifiable risk factors of obesity in Korean children. According to the life-course approach, preschool-aged children (<5 years) are influenced by their parents rather than individual habits because they are under mostly parental care. Elementary school-aged children (6 to 11 years) are affected by overlapping individual and parental effects. This may mean that the establishment of individual behavior patterns begins during this period. The conditions of poor eating habits such as skipping meals, eating out, and high fat intake, along with low physical activity, facilitate increased obesity among adolescents (12 to 18 years). Notably, adolescent girls show high rates of both underweight and obesity, which may lead to the development of NCDs in their offspring. Therefore, the problem of NCDs is no longer limited to adults, but is also prevalent among children. In addition, early intervention offers cost-effective opportunities for preventing NCDs. Thus, children need primary consideration, adequate monitoring, diagnosis, and treatment to reduce the burden of NCDs later in adulthood.

The prevalence of metabolic syndrome in children: a systematic review of the literature

BACKGROUND

Metabolic syndrome has been identified as a condition of childhood relatively recently. The aim in this study was to describe the prevalence of metabolic syndrome in children allowing for differences in metabolic syndrome definitions.

METHODS

This was a systematic review of the OVID, EMBASE, and CINAHL databases, capturing details of overall prevalence and prevalence within groups categorized by obesity, gender, age, and ethnicity.

RESULTS

In all, 378 studies published since 2003 were identified, and of these 85 papers were included in the present review. When all studies were considered, the median prevalence of metabolic syndrome in whole populations was 3.3% (range 0%-19.2%), in overweight children was 11.9% (range 2.8%-29.3%), and in obese populations was 29.2% (range 10%-66%). Within-study analyses confirmed higher prevalence for obese compared to overweight (P=0.012) and obese compared to nonobese, nonoverweight children (P<0.001). Within-study analyses also revealed higher median metabolic syndrome prevalence for boys compared to girls (5.1% versus 3.0%, P<0.001) and also in older compared with younger children (5.6% versus 2.9%, P=0.001). Limited evidence was found to suggest differences between ethnic groups, and there were insufficient studies to determine whether metabolic syndrome prevalence was increasing over time.

CONCLUSIONS

This is the first systematic review of all of the relevant literature. It describes the magnitude of associations between metabolic syndrome and obesity, age, and gender. We find evidence that ethnicity and geography may be important to metabolic syndrome prevalence in children and these associations require further study.

Association between insulin-like growth factor binding protein-2 levels and cardiovascular risk factors in Korean children

Emerging evidence has indicated that insulin-like growth factor binding protein-2 (IGFBP-2) may be involved in the development of obesity and insulin resistance like IGFBP-1. The aim of this study was to measure serum IGFBP-2 levels in overweight and obese children and to compare these levels with those of controls. We also analyzed the associations between IGFBP-2 and insulin sensitivity indices and cardiovascular risk factors. 134 Korean children including 55 overweight and 59 obese subjects were enrolled. We measured anthropometric values and determined fasting serum levels of IGFBP-2, glucose, insulin, lipid profiles, and insulin sensitivity indices including the homeostatic model assessment of insulin resistance (HOMA-IR) and the Quantitative Insulin Sensitivity Check Index (QUICKI). The subjects were subgrouped based on body mass index (BMI) and pubertal stage, and association analyses between IGFBP-2 levels and measured factors were performed in each group. Serum IGFBP-2 levels in overweight or obese children were significantly lower than those of controls regardless of pubertal development. Serum IGFBP-2 levels were negatively correlated with weight, BMI, waist circumference, fasting insulin levels, and HOMA-IR but were positively correlated with QUICKI. The associations were stronger in pubertal children than those in prepubertal children. However, no association was observed between serum IGFBP-2 levels and auxological or metabolic parameters in children with normal BMIs. These results suggested that IGFBP-2 might be a promising marker for early recognition of insulin resistance, particularly in overweight or obese children, regardless of pubertal stage.

Associations between Fatness, Fitness, IGF and IMT among Obese Korean Male Adolescents

BACKGROUND

The purpose of this study was to investigate the association between obesity, fitness levels and cardiovascular (CVD) risk factors, and to identify the correlation between of insulin-like growth factor (IGF)-1, IGF binding protein-3 (IGFBP-3), and carotid intima media thickness (IMT) in Korean adolescents.

METHODS

A total of 225 high school males with a mean age of 16.96±0.23 years participated in this study, and their fatness and fitness levels, fasting glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), blood lipids, IGF-1, IGFBP-3, and IMT were measured.

RESULTS

The results showed that total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), fasting insulin, HOMA-IR, IGF-1, and IGFBP-3 levels were significantly higher in the most obese group than in the other two groups (tertiles). Muscular and cardiopulmonary fitness were negatively associated with weight, body mass index (BMI), fat mass, body fat, waist circumference (WC), fasting insulin, HOMA-IR, and IMT. IGF-1 and IGFBP-3 levels were correlated with WC, hip circumference (HC), fasting glucose, TG, HDL-C, fasting insulin, and HOMA-IR. IMT levels were significantly associated with weight, BMI, muscle mass, fat mass, percent body fat, WC, HC, systolic blood pressure, diastolic blood pressure and high-sensitivity C-reactive protein.

CONCLUSION

There was a significant association between increased obesity and decreased fitness and HOMA-IR, IGF, and IMT among adolescents.

Serum CA125 concentration has inverse correlation with metabolic syndrome

Serum carbohydrate antigen 125 (CA-125) is a marker of ovarian cancer and obesity that is related with an increased risk of ovarian cancer. Obesity is a key factor of metabolic syndrome. We evaluated the relationship between CA-125 concentration and metabolic syndrome. The data from subjects who had any cancer and chronic infection were excluded. The data of 12,196 healthy Korean women were analyzed. After CA-125 concentration was divided by quartiles, the prevalence of metabolic syndrome and its components were compared. The lowest quartile of CA-125 compared with the highest quartile showed elevated values of most of metabolic parameters. In addition, as the quartile of CA-125 increased, metabolic derangement decreased. Increased numbers of metabolic syndrome components showed an inverse association with CA-125 levels (P < 0.001). The odds ratio (OR) for the lowest CA-125 quartile vs the highest CA-125 quartile significantly increased in the presence of metabolic syndrome (OR = 1.202, 95% Confidence Interval [CI] 1.013-1.423), elevated triglyceride (OR = 1.381, 95% CI 1.167-1.633), and low high-density lipoprotein cholesterol (OR = 1.168, 95% CI 1.039-1.312). The presence of metabolic syndrome, elevated triglyceride, or low high-density lipoprotein cholesterol negatively correlates with CA-125 concentration.

Carcinoembryonic antigen level can be overestimated in metabolic syndrome

Carcinoembryonic antigen (CEA) levels can be affected by many factors and metabolic syndrome is also a candidate. This study examined the relationship between CEA levels and metabolic syndrome using the data of 32,897 healthy Koreans. Fecal occult blood tests were also performed. Subjects with colorectal carcinoma were excluded. Subjects were classified by their smoking status, metabolic syndrome and its components. Prevalence of metabolic syndrome and its all components showed a significant increase according to the quartile of serum CEA concentration (P < 0.001). Increased numbers of metabolic syndrome components showed a positive association with CEA levels (P-trend < 0.001). The odds ratios for the highest CEA quartile vs the lowest serum CEA quartile significantly increased in the presence of metabolic syndrome and its components. After adjusting for age, gender and smoking status, metabolic syndrome, low high density lipoprotein cholesterol and elevated blood pressure had higher odds ratios (OR) of the highest CEA quartile compared with the lowest serum CEA quartile (OR = 1.125, 95% CI = 1.030 to 1.222, P = 0.009; OR = 1.296, 95% CI = 1.195 to 1.405, P < 0.001; OR = 1.334, 95% CI = 1.229 to 1.448, P < 0.001, respectively). These results indicate that metabolic syndrome is associated with CEA value, which may lead to a misunderstanding of the CEA levels.

Prevalence of abdominal obesity in adolescents: a systematic review

The objectives of this study were to (i) review extant literature on the prevalence of abdominal obesity (AO) in adolescents of both sex (10-19 years old); (ii) analyse the cut-off points used for the diagnosis of AO and (iii) compare its prevalence between developed and developing countries. The search was carried out using online databases (MEDLINE, Web of Science, EMBASE, SPORTDiscus, SCIELO and BioMed Central), references cited by retrieved articles and by contact with the authors, considering articles published from the establishment of the databanks until 19 October 2009. Only original articles and those using waist circumference in the diagnosis were considered. Twenty-nine studies met the inclusion criteria. Fourteen of these studies were performed in developed countries. The prevalence of AO varied from 3.8% to 51.7% in adolescents from developing countries. The range of results was smaller among developed countries; with values from 8.7% to 33.2%. Eighteen different cut-off points were used. It was concluded the AO prevalence is high among adolescents, but is not clear what sex has a higher proportion and it is greater in adolescents from developing countries; however, there is no consensus in the literature about the criteria to be used.

Prevalence of the metabolic syndrome among female Kuwaiti adolescents using two different criteria

Overweight and obesity are highly prevalent in Kuwait and they are associated with the metabolic syndrome (MS). The present study aims to assess the prevalence of the MS among Kuwaiti female adolescents aged 10-19 years. A cross-sectional random sample of 431, apparently healthy, Kuwaiti female adolescents drawn from several randomly selected schools was studied for the prevalence of the MS using the International Diabetes Federation (IDF) and the National Cholesterol Education Program Third Adult Treatment Panel (ATP III) modified for age diagnostic criteria. Clinical assessment included measurements of waist circumference, blood pressure, fasting blood glucose, HDL and TAG. Whichever criteria are used, the prevalence of the MS among female Kuwaiti adolescents was found to be high, which indicates an urgent need for intervention programmes to prevent increased CVD and type 2 diabetes mellitus. The IDF criteria tend to give higher values for the prevalence of the MS in comparison with the modified ATP III criteria (14.8 v. 9.1 %). There have been no diagnostic criteria specific for the MS for the Gulf Arab population as yet.

Components of the Metabolic Syndrome among a Sample of Overweight and Obese Costa Rican Schoolchildren

Background

The term “pediatric metabolic syndrome” includes a cluster of cardiovascular risk factors such as insulin resistance, dyslipidemia (including increased triglycerides and decreased HDL cholesterol), hypertension, and obesity in children. No studies have been performed on this syndrome in a pediatric population in Costa Rica.

Objective

To establish the prevalence of metabolic syndrome and its components in 8- to 10-year old prepuberal overweight and obese schoolchildren.

Methods

This cross-sectional survey was conducted in 214 overweight and obese boys and girls, aged 8 to 10 years, who were selected from six urban schools from San José, Costa Rica. Anthropometric measurements and determinations of blood glucose, insulin, triglycerides, total cholesterol, HDL cholesterol, and high-sensitivity C-reactive protein (hs-CRP) were performed. The home-ostasis model assessment of insulin resistance (HOMA-IR) index and the Castelli index were calculated to assess insulin resistance and cardiovascular risk, respectively. Social and lifestyle variables were obtained through validated questionnaires.

Results

A total of 110 boys and 104 girls participated in this study; 37.9% of them were overweight and 62.1% were obese. Compared with boys, girls were more sedentary and had higher insulin levels (16.05 ± 10.45 μIU/mL vs. 12.72 ± 7.63 μIU/mL, p = .008), body fat (36.5% vs. 30.9%, p < .001), and HOMA-IR indexes (3.5 ± 2.4 vs. 2.8 ± 1.7, p = .014) but lower HDL cholesterol (0.99 ± 0.23 mmol/L vs. 1.08 ± 0.27 mmol/L, p = .009). Obese children had significantly higher mean serum concentrations of insulin, hs-CRP, and triglycerides and higher insulin resistance (estimated by HOMA-IR) than overweight children, but lower mean serum levels of HDL cholesterol. The prevalence of metabolic syndrome in the study population was 5.6%. Other risk factors for developing cardiovascular disease and type 2 diabetes had high prevalence rates among the children: sedentarism (40.6%), family history of type 2 diabetes (73.3%), high LDL cholesterol levels (≥ 2.84 mmol/L) (57.0%), hyperinsulinemia (> 10.5 μIU/mL) (59.8%), insulin resistance (estimated by HOMA-IR ≥ 2.4) (55.1%), and total cholesterol (> 4.39 mmol/L) (60.7%). Children with metabolic syndrome had significantly higher body mass indexes, glucose levels, and triglyceride levels and lower HDL cholesterol levels than children without metabolic syndrome. Insulin had a very strong positive correlation with HOMA-IR values ( r = 0.982), and hs-CRP had a mild positive correlation with body mass index ( r = 0.296) and body fat ( r = 0.320).

Conclusions

This study reported a prevalence of 5.6% of metabolic syndrome among a sample of Costa Rican overweight and obese prepuberal children. Lifestyle interventions focusing on weight reduction and increasing physical activities should be promoted by education and health authorities in order to avoid the early development and onset of type 2 diabetes and atherosclerosis in childhood.