Which measures of adiposity are related to Australian adolescent's perception of their weight?

Obesity and the risk of Multiple Sclerosis. The role of Leptin

OBJECTIVE

To investigate the effects of leptin on different T-cell populations, in order to gain more insight into the link between leptin and obesity.

METHODS

Three hundred and nine RRMS patients and 322 controls participated in a cross-sectional survey, to confirm whether excess weight/obesity in adolescence or early adulthood increased the risk of MS. Serum leptin levels were determined by ELISA. MBP_83-102 , and MOG_63-87 peptide-specific T cells lines were expanded from peripheral blood mononuclear cells. Leptin receptor expression was measured by RT-PCR and flow cytometry. Bcl-2, p-STAT3, pERK1/2, and p27^kip1 expression were assayed using ELISA, and apoptosis induction was determined by Annexin V detection. Cytokines were assessed by ELISPOT and ELISA, and regulatory T cells (Tregs) by flow cytometry.

RESULTS

Logistic regression analysis, showed excess weight at age 15, and obesity at 20 years of age increased MS risk (OR = 2.16, P = 0.01 and OR = 3.9, P = 0.01). Leptin levels correlated with BMI in both groups. The addition of Leptin increased autoreactive T-cell proliferation, reduced apoptosis induction, and promoted proinflammatory cytokine secretion. Obese patients produced more proinflammatory cytokines compared to overweight/normal/underweight subjects. Inverse correlation was found between leptin levels and circulating Treg cells (r = -0.97, P < 0.0001). Leptin inhibited Treg proliferation. Effects of leptin on CD4⁺ CD25^- effector T cells were mediated by increased STAT3 and ERK1/2 phosphorylation, and down modulation of the cell cycle inhibitor P27^kip1 . In contrast, leptin effects on Tregs resulted from decreased phosphorylation of ERK1/2 and upregulation of p27^kip1 .

INTERPRETATION

Leptin promotes autoreactive T-cell proliferation and proinflammatory cytokine secretion, but inhibits Treg-cell proliferation.

Factors Influencing Parents' and Children's Misperception of Children's Weight Status: a Systematic Review of Current Research

PURPOSE OF REVIEW

Misperception of children's weight status is prevalent among parents and children themselves and may impact parents' and children's health behaviors. This study was conducted in order to provide a descriptive systematic review of research on factors influencing parents' and children's misperceptions of children's weight status published in the past 5 years.

RECENT FINDINGS

Factors studied most often in relation to parents' and children's misperception included children's weight status, gender, and age, as well as parents' weight status, parental education levels and socioeconomic status, and ethnicity. Most determinants that were found to have a significant influence on misperception in parents also did in children. The literature on misperception of children's weight status is extensive. Most determinants assessed in included studies were known determinants of childhood obesity. Further research should be directed toward better understanding the impact of weight status perception (whether it is accurate or not) on health behaviors and weight gain over time.

Am I Overweight? A Longitudinal Study on Parental and Peers Weight-Related Perceptions on Dietary Behaviors and Weight Status Among Adolescents

OBJECTIVE

An investigation of the interplay between various types of adolescents' perceptions of weight status in predicting adolescents' nutrition behavior and their body mass was conducted. In particular, it was hypothesized that the relationship between parental and peers' perceptions of their own weight status (reported by adolescents) and objectively measured weight status of adolescents would be mediated by three types of adolescents' weight status perceptions (adolescents' own weight perceptions, parental perceptions of adolescents' weight status perceived by participants, and peers' perceptions of adolescents' weight status perceived by participants) and by adolescents' nutrition behaviors.

DESIGN

Data were collected twice, with a 13-month follow-up. Participants (N = 1096) were aged 14-20, with BMI ranging from 16.20 to 41.21. Multiple mediation analysis with two sequential mediators was applied.

MAIN OUTCOME MEASURES

At the baseline adolescents completed the questionnaire assessing their nutrition behaviors and weight status perceptions. Weight and height were measured objectively at baseline and follow-up.

RESULTS

Two types of weight perceptions (adolescents' own weight status perceptions, peers' perceptions of adolescents' weight status reported by participants), and adolescents' nutrition behaviors mediated the relationship between the others' own weight perceptions and adolescents' weight status. No indirect effects of others' own weight perceptions on adolescents' weight status through parental perceptions were found.

CONCLUSION

Adolescents' nutrition behaviors and body weight status depend on what they think about their own weight status and what they think of their peers' perceptions, but do not depend on what adolescents think of their parents' perceptions.