Metabolic syndrome in the pediatric population: a short overview

Caveolin-1 rs1997623 variant and adult metabolic syndrome—Assessing the association in three ethnic cohorts of Arabs, South Asians and South East Asians

Background: Animal and cell model studies have implicated CAV1 in the pathophysiology of metabolic disorders. Our previous studies demonstrated a potential association of CAV1 rs1997623 C/A variant with pediatric metabolic syndrome (MetS) in Arab children. In the present study, we evaluate whether the CAV1 variant associates with MetS Arab adults as well. The association signal is further examined for ancestry-specific variation by considering cohorts of other ethnicities.

Method: The CAV1 rs1997623 was genotyped in three cohorts of Arab (n = 479), South Asian (n = 660), and South East Asian (n = 362) ethnic adults from Kuwait. MetS status of the individuals was diagnosed using the IDF criteria (presence of central obesity and at least two abnormalities out of: elevated TG, low HDL, hypertension, or T2D). The quantitative measure of MetS was calculated as siMS = 2 × WC/Height + FBG/5.6 + TG/1.7 + SBP/130–HDL/1.02 for males or HDL/1.28 for females. Allelic associations with quantitative and dichotomous MetS traits were assessed using linear and logistic regression models adjusted for age and sex. In addition, empirical p-values (P_emp) were generated using max(T) permutation procedure based on 10,000 permutations.

Results: The CAV1 variant was significantly associated with MetS status (OR = 1.811 [1.25–2.61]; p-value = 0.0015; P_emp = 0.0013) and with siMS (Effect size = 0.206; p-value = 0.0035; P_emp = 0.0028) in the cohort of Arab individuals. The association was weak and insignificant in the South Asian and South East Asian cohorts (OR = 1.19 and 1.11; p-values = 0.25 and 0.67, respectively).

Conclusion: The reported association of CAV1 rs1997623 C/A with MetS in Arab pediatric population is now demonstrated in an adult Arab cohort as well. The weak association signal seen in the Asian cohorts lead us to propose a certain extent of ethnic-specificity in CAV1 rs1997623 association with MetS.

Association of Serum Retinol Concentrations With Metabolic Syndrome Components in Iranian Children and Adolescents: The CASPIAN-V Study

Background

As a fat-soluble vitamin, vitamin A plays a crucial role in adipogenesis, lipolysis, insulin resistance, and obesity. However, it is still unclear whether they are associated with cardiometabolic risk factors in children and adolescents. The current study aimed to determine the association between serum retinol concentration and the cluster of metabolic syndrome components among children and adolescents.

Methods

This nationwide cross-sectional study was performed on 2,518 students aged 7–18 years from the Childhood and Adolescence Surveillance and Prevention of Adult Non- communicable disease (CASPIAN-V) study. Students were selected via multistage cluster sampling method from 30 provinces of Iran in 2015. Multivariable logistic regression was used to assess the association of serum retinol concentration with metabolic syndrome (MetS) components.

Results

Overall, the mean (SD) age of study participants was 12.16 (3.04) years, and 44.9% (n = 1,166) of them were girls. The mean serum retinol concentration was 1.48 ± 1.55 μmol/L and vitamin A deficiency was observed among 19.7% (95% CI: 18.2–21.3) of study subjects. The results of the logistic regression analysis showed that increasing serum retinol concentrations were associated with an increased likelihood of developing obesity (OR: 1.12, 95% CI: 1.04, 1.20), abdominal obesity (OR: 1.07, 95% CI: 1.01, 1.14), low high-density lipoprotein cholesterol (HDL-C) (OR: 1.10, 95% CI: 1.04, 1.16) and high fasting blood glucose (FBG) (OR: 1.21, 95% CI: 1.10, 1.35), whereas it was associated with a decreased odds of developing high blood pressure (OR: 0.82, 95% CI: 0.73, 0.93). Nevertheless, there was no statistically significant association between metabolic syndrome itself and retinol concentration (OR: 1.02, 95% CI: 0.88, 1.18).

Conclusion

We found that serum retinol concentration was positively associated with metabolic syndrome components such as obesity, low HDL-C, and high FBG, but not with metabolic syndrome itself.

Fasting insulin resistance affects the prevalence of metabolically healthy obesity in Brazilian adolescents

AIM

We aimed to assess the influence of fasting insulin resistance on metabolically healthy obesity (MHO) prevalence in adolescents and to identify associated factors.

METHODS

This retrospective, registry-based, cross-sectional study included 418 (51.9% girls) 10- to 18-year-old adolescents with obesity from a tertiary outpatient clinic in Sao Paulo, Brazil, between 2009 and 2013. The prevalence of MHO was estimated according to two definitions: (i) no cardiometabolic risk factors (CMRF) by the International Diabetes Federation parameters and (ii) no CMRF and homeostatic model assessment for insulin resistance <3.16. Adjusted prevalence ratios and 95% confidence intervals (CI) evaluated the association of gender, age, pubertal stages, skin colour and degree of obesity with MHO.

RESULTS

Metabolically healthy obesity prevalence was lower in definition II than definition I (12.7%; 95% CI 9.1-16.3% versus 43.1%; 95% CI 38.0-48.2%, respectively). Adjusted results showed negative association between severe obesity and MHO by both definitions (p ≤ 0.01). Male and later pubertal stages were also less likely to have MHO, but neither remained significant in definition II.

CONCLUSION

Metabolically healthy obesity prevalence decreased when insulin resistance was part of the definition. Detecting pre-clinical insulin resistance may improve the management of treatment-seeking adolescents, especially when they present no CMRF.

High Prevalence of Rare Monogenic Forms of Obesity in Obese Guadeloupean Afro-Caribbean Children

CONTEXT

The population of Guadeloupe Island exhibits a high prevalence of obesity.

OBJECTIVE

We aimed to investigate whether rare genetic mutations in genes involved in monogenic obesity (or diabetes) might be causal in this population of Afro-Caribbean ancestry.

DESIGN AND SETTING

This was a secondary analysis of a study on obesity conducted in schoolchildren from Guadeloupe in 2013 that aimed to assess changes in children's profiles after a lifestyle intervention program. Through next-generation sequencing, we sequenced coding regions of 59 genes involved in monogenic obesity or diabetes in participants from this study.

PARTICIPANTS AND INTERVENTIONS

A total of 25 obese schoolchildren from Guadeloupe were screened for rare mutations (nonsynonymous, splice-site, or insertion/deletion) in 59 genes.

MAIN OUTCOME MEASURES

Correlation between phenotypes and mutations of interest.

RESULTS

We detected five rare heterozygous mutations in five different children with obesity: MC4R p.Ile301Thr and SIM1 p.Val326Thrfs*43 mutations that were pathogenic; SIM1 p.Ser343Pro and SH2B1 p.Pro90His mutations that were likely pathogenic; and NTRK2 p.Leu140Phe that was of uncertain significance. In parallel, we identified seven carriers of mutations in ABCC8 (p.Lys1521Asn and p.Ala625Val) or KCNJ11 (p.Val13Met and p.Val151Met) that were of uncertain significance.

CONCLUSIONS

We were able to detect pathogenic or likely pathogenic mutations linked to severe obesity in >15% of this population, which is much higher than what we observed in Europeans (∼5%).

Vitamin D Status, Insulin Resistance, Leptin-To-Adiponectin Ratio in Adolescents: Results of a 1-Year Lifestyle Intervention

AIM:

We aimed to study the relationships between circulating 25-hydroxyvitamin D [25(OH)D], insulin resistance and leptin-to-adiponectin (L/A) ratio in Guadeloupean children and adolescents and to analyse the changes in 25(OH)D levels after a 1-year lifestyle intervention program.

METHODS:

25(OH)D concentrations were measured via a chemiluminescence assay. Cardiometabolic risk factors, homoeostasis model assessment of insulin resistance (HOMA-IR), and adipokines were measured. The lifestyle intervention included dietary counselling, regular physical activity.

RESULTS:

Among 117 girls and boys (11–15 years old, 31.6% obese), 40% had vitamin D deficiency (25(OH)D levels < 20 ng/mL). With linear regression models where 25(OH)D and HOMA-IR acted as independent variables and age, sex, BMI, L/A ratio as covariates, 25(OH)D was significantly associated with HOMA-IR alone (P = 0.036). HOMA-IR was also associated with BMI z-score ≥ 2, L/A ratio and an interaction term BMI z-score ≥ 2*L/A ratio (P < 0.001 for all). After one year, in 78 children/adolescent, mean serum 25(OH)D increased significantly from 21.4 ± 4.9 ng/mL at baseline to 23.2 ± 6.0 after 1 year; P = 0.003 whereas BMI z-score, HOMA-IR and L/A ratio decreased significantly (P = 0.003, P < 0.001 and P = 0.012; respectively).

CONCLUSION:

The association between 25(OH)D and HOMA-IR, independently of obesity and the high prevalence of vitamin D deficiency should be considered in order to prevent the later incidence of T2DM. A healthy lifestyle including non-sedentary and outdoor activities could be a way for improving vitamin D status.

Ghrelin, adipokines, metabolic factors in relation with weight status in school-children and results of a 1-year lifestyle intervention program

BACKGROUND

Overweight in Guadeloupe is a public health matter affecting children and adults. In the present study we evaluated the metabolic profile, including serum ghrelin, leptin and adiponectin levels, in normal weight, overweight and obese school children and we analyzed the potential changes in anthropometric and metabolic risk factors after a 1-year lifestyle intervention program.

METHODS

Parameters were assessed at baseline and at 1 year. Three groups (G) were defined according the International Obesity Task Force reference values, G1: normal weight / G2: overweight / G3: obese. The lifestyle intervention included dietary counseling, regular physical activity and family support.

RESULTS

A total of 120 children (G1: n = 44, G2: n = 39, G3: n = 37), aged 11- 15 years and 59 % girls were enrolled. Obese children showed significant lower HDL-C, adiponectin and ghrelin concentrations, higher triglycerides, fasting blood glucose, insulin and leptin levels and also higher frequencies of abdominal obesity (G1: 2.3 %, G2: 28.2 %, G3: 73 %) and insulin resistance (GI: 39 %, G2: 72 %, G3: 89 %) than the other groups. In the overall sample, the linear regressions exploring the associations of ghrelin, adiponectin and leptin with age, gender, BMI z-score, HOMA-IR and tanner stage as independent variables showed strong associations of leptin levels with weight status and insulin resistance at baseline. The models accounted for 58 % of variability in leptin levels compared with 26 and 15 % for adiponectin and ghrelin levels respectively. In 83 children who completed the program, significant decreases in BMI z-score in overweight and obese children were noted. Leptin levels decreased significantly only in the obese group whereas adiponectin concentrations increased significantly in the three groups, In obese children, a significant correlation was found between changes in BMI Z-score, and changes in leptin levels (r = 0.39; P = 0.049) but not with changes in adiponectin levels.

CONCLUSIONS

Abdominal obesity and insulin resistance were highly prevalent in obese children highlighting their risk of metabolic complications in adulthood. A 1-year long lifestyle intervention was associated with improvement in BMI z-score and metabolic parameters.

Is lower uric acid level better? A combined cross-sectional and longitudinal study in the elderly

The relationship between metabolic syndrome (MetS) and uric acid (UA) has been explored in many studies, but there is paucity of information on hypo-uricemia and MetS. The current study aimed to elucidate the relationship between the lower end of UA and MetS in elderly. Subjects aged ≥ 60 years who underwent routine health checkups were enrolled, and 10,579 were eligible for analysis. A cross-sectional study was first performed to determine the correlation between MetS and UA. The subjects were divided into two groups according to the lowest male MetS prevalence in each UA level (UA ≤ 5 and >5 mg/dl). A longitudinal study then excluded subjects with MetS at baseline to validate the UA level of those with the lowest incidence of MetS. In the prevalence of MetS in different UA levels, there was a J-shaped curve in males but a linear relationship in females. In males, waist circumference, systolic blood pressure, high-density lipoprotein, and triglyceride were correlated with UA in univariate analysis, but high-density lipoprotein became insignificant in multivariate analysis in UA >5 mg/dl (UA-high). Only fasting plasma glucose (FPG) was significantly related to UA ≤ 5 mg/dl (UA-low). The UA level of 4.5-5 mg/dl had the lowest risk of having MetS in odds ratio, log-rank test, and hazard ratio. A J-shaped phenomenon exists between UA and MetS in elderly men but not in elderly women and FPG seem to be the key factor in this. Lower UA does not provide benefits in elderly men. The new UA control strategy for the elderly warrants further investigation.

Metabolic syndrome in Turner syndrome and relation between body composition and clinical, genetic, and ultrasonographic characteristics

BACKGROUND

An increased relative risk of diabetes, ischemic heart disease, atherosclerosis, and hypertension have been reported in Turner syndrome (TS) patients. No data are currently available on the prevalence of metabolic syndrome in TS subjects. We evaluated the frequency of metabolic syndrome in obese and nonobese patients with TS.

PATIENTS AND METHODS

We evaluated 85 TS patients (27.05 ± 11.17 years). Obesity was defined as standard deviation score body mass index (SDS-BMI) ≥ 2 or BMI ≥ 30 kg/m(2) in adult patients. We classified metabolic syndrome according to the International Diabetes Federation (IDF). Hepatic ultrasound was performed in all girls.

RESULTS

The prevalence of metabolic syndrome was 4.7% (12.5% obese and 4.3% nonobese, P=0.16) and associated with visceral adiposity (P=0.008). Abnormalities in glucose metabolism and hypertension were not associated with genetic or therapeutic factors. The karyotype 45,X was associated with atherogenic profile. Pathological waist circumference was more frequent in girls treated with estro-progestin (P=0.03). Evidence of fatty liver was associated with metabolic syndrome (P=0.03) and insulin resistance (P=0.05). Elevated liver enzymes were found in 15 subjects and were not related to treatment or ultrasound abnormalities.

CONCLUSIONS

Prevalence of each component of metabolic syndrome in TS patients is partially influenced by genetic makeup and treatment. Hepatosteatosis was associated with metabolic syndrome and insulin resistance, but not to elevated liver enzymes.

Emotional psychopathology and increased adiposity: follow-up study in adolescents

Based on data from a three-year longitudinal study, we assess the effect, according to gender, of emotional psychopathology in preadolescence on anthropometric and body composition parameters in adolescence (N = 229). Psychopathology was assessed using the Screen for Childhood Anxiety and Related Emotional Disorders, the Children's Depression Inventory and the MINI-International Neuropsychiatric Interview for Kids. Body fat percentage (%BF), waist circumference (WC) and body mass index (BMI) were also determined. Following analysis with adjusted multiple regression models, the results indicated that symptoms of depression and separation anxiety were significantly associated with increased WC and BMI in boys, and that somatic symptoms were associated with increased WC and %BF in girls. Diagnosis of social phobia, panic disorder or dysthymia led to significantly increased WC and/or BMI in boys and dysthymia increased WC in girls. These findings suggest that emotional psychopathology in preadolescence is associated with increased weight gain and abdominal fat in adolescence.

Influence of obesity on nocturnal oxygen saturation in young children

Obesity is increasing worldwide and it is accompanied by major health effects. In adults and school-aged children, obesity is associated with decreased respiratory function, which may lead to disturbed sleeping and subsequently difficulties in concentration and behavioural disorders. The evidence for the association between obesity and decreased respiratory function in younger children is scarce. To explore the association between body weight and nocturnal respiratory function in young children, 1 to 3 years old, nocturnal pulse oximetry was performed at home. Children with tonsillar hypertrophy were excluded. Percentage of time with oxygen saturation (SpO(2)) <95 % was measured and its association with body mass index (BMI) for age z scores was analysed. Pulse oximetric data of 51 children, including 18 children with a BMI for age above +2 standard deviations, were obtained for this study. Linear regression analysis, correction for gender and parental smoking, showed a positive association between the natural logarithm of SpO(2) <95 % and BMI for age z score [regression coefficient (β) 0.19, 95 % confidence interval 0.00-0.39].

CONCLUSION

In young children, higher body weight is associated with a decrease in nocturnal oxygen saturation.

Predictive value of serum uric acid levels for the diagnosis of metabolic syndrome in adolescents

OBJECTIVE

To evaluate the cause-effect relationships between serum levels of uric acid (UA) and metabolic syndrome (MetS) in an adolescent-male cohort that was followed for 2.7 years.

STUDY DESIGN

We enrolled male adolescents aged between 10 and 15 years at the baseline. A total of 613 subjects were divided into quartiles according to their UA levels, from UA-1 (the lowest) to UA-4 (the highest).

RESULTS

After the mean follow-up period of 2.7 ± 0.97 years, 19 (3.1%) subjects developed MetS. Waist circumference (WC), systolic blood pressure, high density lipoprotein cholesterol (HDL-C), and log triglyceride levels were significantly related to baseline UA levels. Compared with the UA-1 group, subjects in the UA-4 group had significantly higher OR for abnormal WC, blood pressure, and HDL-C at the end of follow-up and had a 6.39-fold higher OR (95% CI 1.41-29.08; P < .05) for having MetS. Subjects with UA >7.6 mg/dL had a 4.32 (95% CI 1.57-11.93) higher risk of developing MetS.

CONCLUSIONS

In this longitudinal study, we found that serum UA is correlated with future WC, systolic blood pressure, triglyceride, and HDL-C and is a risk factor for developing MetS. UA might be valuable in predicting adolescent MetS.

Hyperuricemia in obese children and adolescents: the relationship with metabolic syndrome

The prevalence of hyperuricemia in obese children and adolescents and its association with metabolic syndrome are largely unknown. The objective of our study was to characterize hyperuricemia in relation to metabolic syndrome in Japanese children and adolescents with obesity. Between 2005 and 2008, we performed a cross-sectional study of 1,027 obese children and adolescents aged 6-14 years. Based on the reference value of serum uric acid we had established previously, hyperuricemia was defined as one standard deviation over the mean value at each age. The diagnosis of metabolic syndrome was made based on the Japanese criteria for children. A total of 213 children and adolescents (20.7%) was found to have hyperuricemia. The prevalence of hyperuricemia was significantly higher in the male gender and older age group. Sixty-five out of 213 subjects with hyperuricemia (30.5%) had metabolic syndrome, whereas 111 out of 814 subjects without hyperuricemia (13.6%) had metabolic syndrome. The most common abnormal component of metabolic syndrome was triglyceride, followed by diastolic blood pressure, systolic blood pressure, fasting blood glucose, and HDL-cholesterol. Such a tendency was almost identical between the two groups. We concluded that considering the association between hyperuricemia and metabolic syndrome in obese Japanese children and adolescents, the role of hyperuricemia in metabolic syndrome should receive more attention, beginning in early childhood.