Differential significance of plasma visfatin concentrations according to adiposity in children and adolescents

Effects of low-glycemic index diet on plasma adipokines in obese children

BACKGROUND

A low-glycemic index (GI) diet may modulate adipocyte-produced adipokines linking to insulin resistance.

METHODS

The stored plasma samples from the RCT of a low-GI vs. conventional diet in obese children were analyzed for adipokines: leptin, adiponectin, resistin, and visfatin. Their relationships with clinical outcomes were assessed.

RESULTS

Fifty-two participants completed the 6-month intervention trial (mean age: 12.0 ± 2.0 years, 35 boys). Both groups had significantly decreased BMI z-scores from baseline whereas the low-GI group had significant reduction in fasting insulin and HOMA-IR. There were no differences in adipokines between the groups before and after the intervention. However, there was an association between baseline leptin and the change of fat mass index (FMI) but not the insulin resistance in both groups. The higher the baseline leptin was, the lower the changes were for FMI after the intervention.

CONCLUSION

Despite no demonstrable effect of low-GI diet on plasma adipokines, the higher baseline leptin was correlated with lower reduction of fat mass. Leptin resistance may have a detrimental effect on the reduction of adiposity in obese children. Baseline leptin could be a useful predictor of the change in body composition in an obesity intervention trial.

IMPACT

Leptin resistance may have a detrimental effect in reducing the adiposity in obese children. This study is the first of its kind to compare the plasma adipokine concentrations of obese children on low-GI diet and conventional diet. We found that serum leptin was significantly correlated with the reduction of BMI z-score and FMI in both groups. Baseline leptin could be a useful predictor of the change in body composition in an obesity intervention trial.

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.

From Placenta to Polycystic Ovarian Syndrome: The Role of Adipokines

Adipokines are cytokines produced mainly by adipose tissue, besides many other tissues such as placenta, ovaries, peripheral-blood mononuclear cells, liver, muscle, kidney, heart, and bone marrow. Adipokines play a significant role in the metabolic syndrome and in cardiovascular diseases, have implications in regulating insulin sensitivity and inflammation, and have significant effects on growth and reproductive function. The objective of this review was to analyze the functions known today of adiponectin, leptin, resistin, and visfatin from placenta throughout childhood and adolescence. It is well known now that their serum concentrations during pregnancy and lactation have long-term effects beyond the fetus and newborn. With regard to puberty, adipokines are involved in the regulation of the relationship between nutritional status and normal physiology or disorders of puberty and altered gonadal function, as, for example, premature pubarche and polycystic ovarian syndrome (PCOS). Cytokines are involved in the maturation of oocytes and in the regular progression of puberty and pregnancy.

Serum Visfatin and Leptin in Relation to Childhood Adiposity and Body Fat Distribution: The PIAMA Birth Cohort Study

BACKGROUND/AIMS

Visfatin has been suggested as a marker of visceral adiposity. We hypothesized that visfatin, but not leptin, would be specifically associated with visceral adiposity. We investigated the relation of serum visfatin and leptin with measures of adiposity and body fat distribution in children.

METHODS

Serum leptin and visfatin levels were measured in 1,022 12-year-old children participating in the PIAMA birth cohort. BMI, waist, hip and upper arm circumference were available for all children. Multiple linear regression analyses were conducted to study associations between different anthropometric indices and log serum visfatin and leptin levels.

RESULTS

All anthropometric indices showed positive and strong dose-response relationships with serum leptin. Visfatin was increased only in children with a high waist-to-hip ratio. The effect size was small compared to those observed for leptin and the association was present in overweight children (n = 133) but not in normal weight children.

CONCLUSION

Serum leptin levels strongly increased with increasing adiposity, but were not related to a specific type of fat distribution. In contrast, serum visfatin was associated only with high waist-to-hip ratio in overweight children. Based on our study we would currently not recommend visfatin as a marker of visceral adiposity in the general population of children.