Psychological well-being and weight-related teasing in childhood obesity: a case-control study

PURPOSE

The prevalence of childhood obesity continues to increase worldwide. The aims of this study were to (1) assess the psychological well-being and rates of teasing of Spanish children with obesity (OG) and compare them with their non-overweight peers (NG), and (2) analyze the mediating role of weight-related teasing on the relation between children's BMI z score and psychological well-being.

METHODS

The cross-sectional study included 50 preadolescents with obesity, matched with non-overweight children according to age, sex, and socioeconomic status, who were assessed via self-report instruments measuring anxiety, depression, self-esteem, and teasing.

RESULTS

The OG reported higher anxiety, depression, and teasing, and lower self-esteem. SEM revealed that children who scored worse on instruments assessing psychological well-being had higher BMI z scores. Weight-related teasing predicted poor psychological well-being scores and weight-related teasing mediated the relation between BMI and psychological well-being.

CONCLUSIONS

The high rates of anxiety, depression, and weight-related teasing, as well as the low self-esteem, which was observed amongst the children with obesity, raise concerns about the quality of life of this population. Furthermore, the finding that weight-related teasing mediated the relationship between BMI and psychological well-being adds to a growing body of research, highlighting the harmful effects of weight-related stigma. Overall, these results highlight the importance of early intervention to assess for, and address, the presence of weight-related teasing and psychological well-being difficulties in preadolescents with obesity.

LEVEL OF EVIDENCE

Level III, case-control study.

Exendin-4 agonist and exendin(9-39)amide antagonist of the GLP-1(7-36)amide effects in liver and muscle

The GLP-1 structurally related peptides exendin-4 and exendin(9-39)amide were found to act, in rat liver and skeletal muscle, as agonist and antagonist, respectively, of the GLP-1(7-36)amide effects on glucose metabolism. Thus, like GLP-1(7-36)amide, exendin-4 increased glycogen synthase a activity and glucose incorporation into glycogen in both tissues and also stimulated exogenous D-glucose utilization and oxidation in muscle. These effects of GLP-1(7-36)amide and exendin-4 were inhibited by exendin(9-39)amide. Our findings provide further support to the proposed use of GLP-1, or exendin-4, as a tool in the treatment of diabetes mellitus. Thus, in addition to the well-known insulinotropic action of the peptides, they act both in liver and in muscle in a manner most suitable for restoration of glucose homeostasis, with emphasis on their positive effects upon glycogen synthesis in the two tissues and on the stimulation of exogenous glucose catabolism in muscle.

Inositolphosphoglycans are possible mediators of the glucagon-like peptide 1 (7-36)amide action in the liver

A potent glycogenic effect for GLP-1(7-36)amide has been found in rat hepatocytes and skeletal muscle, and the specific receptors detected for GLP-1(7-36)amide in these tissue membranes do not seem to be associated to adenylate cyclase. On the other hand, inositolphosphoglycan molecules (IPGs) have been implicated as second messengers in the action of insulin. In a human hepatoma cell line (HEP G-2), we have observed the presence of [125I]GLP-1(7-36)amide specific binding, and a stimulatory effect of the peptide upon glycogen synthesis, confirming the findings in isolated rat hepatocytes. Also, GLP-1(7-36)amide modulates the cell content of radiolabelled glycosylphosphatidylinositols (GPIs), in the same manner as insulin, indicating hydrolysis of GPIs and an immediate and short-lived generation of IPGs. Thus, IPGs could be mediators in the GLP-1(7-36)amide glycogenic action in the liver.

GLP-1(7-36)amide binding in skeletal muscle membranes from streptozotocin diabetic rats

A higher specific binding of GLP-1(7-36)amide is found in skeletal muscle plasma membranes from adult streptozotocin (STZ)-treated rats (insulin-dependent diabetes mellitus model) and from neonatal STZ-treated rats (non insulin-dependent diabetes mellitus model), as compared to that in normal controls; no apparent change in the affinity was observed, that indicating the presence in both diabetic models of an increased number of high affinity binding sites for the peptide. The maximal specific GLP-1(7-16)amide binding in the non insulin-dependent diabetes mellitus model was found to be significantly higher than that in the insulin-dependent diabetes mellitus model. As GLP-1(7-36)amide exerts a glycogenic effect in the rat skeletal muscle, the present data suggest that the action of the peptide in the muscle glucose metabolism may be increased in states of insulin deficiency accompanied or not by insulin resistance.

Potent glycogenic effect of GLP-1(7-36)amide in rat skeletal muscle

GLP-1(7-36)amide is an intestinal post-translational proglucagon product released mainly after carbohydrate ingestion, the glucose dependent insulinotropic and antidiabetogenic actions of which have been documented. In this work, by exploring whether GLP-1(7-36)amide has any effect on the glucose metabolism of the muscle, we have observed that this peptide, at physiological concentrations, exerts in this tissue an increment of the D-[U-14C]glucose incorporated into glycogen, which is accompanied by an increase in the glycogen synthase a activity; also, it stimulates both glucose oxidation and lactate formation. These data indicate that the skeletal muscle is one of the target tissues for GLP-1(7-36)amide, where its insulin-like effect explains, at least in part, its plasma glucose lowering action; thus, GLP-1(7-36)amide may well be implicated in the physiological control of glucose homeostasis after meals, not only by acting as an incretin, but also by directly promoting glucose disposal.