Georgina Loughnan

Self-efficacy in relation to eating behaviour among obese and non-obese women

OBJECTIVE: To assess the effect of a 3 month behaviour modification weight management programme on self-efficacy and anthropometric variables among obese women seeking treatment at an obesity management clinic and to compare self-efficacy among these obese women to non-obese women.DESIGN: Cross sectional.SUBJECTS: A total of 161 non-obese (BMI 22.6±2.9 kg/m2) and 138 obese (BMI 37.7±5.8 kg/m2) women of similar age.MEASUREMENTS: Self-efficacy in relation to eating was assessed by the Weight Efficacy Lifestyle (WEL) questionnaire. Demographic information was obtained by interview and questionnaire in the obese and by questionnaire in the non-obese. Anthropometric measurements were obtained by direct measure in the obese and BMI was calculated from self-reported weight and height in the non-obese.RESULTS: At entry to the programme obese women scored significantly less (P<0.0001) than non-obese women on the WEL (99.4±34.1 vs 139.0±24.9). Women who completed the programme (n=65) demonstrated a decrease in waist circumference of 3.9±5.3 cm, a 10.0±11.5% loss of excess weight and a significant improvement in total WEL score from 106.0±30.3 to 126.5±28.4.CONCLUSION: Improvements in some dimensions of self-efficacy among obese women were of sufficient magnitude to attain scores similar to women of a normal weight. The WEL questionnaire may provide an additional measure of success as well as provide positive feedback and encouragement to the client.

In adults with Prader–Willi syndrome, elevated ghrelin levels are more consistent with hyperphagia than high PYY and GLP-1 levels

OBJECTIVE Prader-Willi syndrome (PWS) is a leading genetic cause of obesity, characterized by hyperphagia, endocrine and developmental disorders. It is suggested that the intense hyperphagia could stem, in part, from impaired gut hormone signaling. Previous studies produced conflicting results, being confounded by differences in body composition between PWS and control subjects. DESIGN Fasting and postprandial gut hormone responses were investigated in a cross-sectional cohort study including 10 adult PWS, 12 obese subjects matched for percentage body fat and central abdominal fat, and 10 healthy normal weight subjects. METHODS PYY[total], PYY[3-36], GLP-1[active] and ghrelin[total] were measured by ELISA or radioimmunoassay. Body composition was assessed by dual energy X-ray absorptiometry. Visual analog scales were used to assess hunger and satiety. RESULTS In contrast to lean subjects (p<0.05), PWS and obese subjects were similarly insulin resistant and had similar insulin levels. Ghrelin[total] levels were significantly higher in PWS compared to obese subjects before and during the meal (p<0.05). PYY[3-36] meal responses were higher in PWS than in lean subjects (p=0.01), but not significantly different to obese (p=0.08), with an additional non-significant trend in PYY[total] levels. There were no significant differences in self-reported satiety between groups, however PWS subjects reported more hunger throughout (p=0.003), and exhibited a markedly reduced meal-induced suppression of hunger (p=0.01) compared to lean or obese subjects. CONCLUSIONS Compared to adiposity-matched control subjects, hyperphagia in PWS is not related to a lower postprandial GLP-1 or PYY response. Elevated ghrelin levels in PWS are consistent with increased hunger and are unrelated to insulin levels.

The effects of obesity and non-pharmacological weight loss on vascular and ventricular function and structure.

Aims:  The mechanisms by which obesity confers increased cardiovascular risk and the effects of moderate weight loss on cardiovascular health are incompletely understood. We sought to characterize the preclinical changes in cardiac and vascular health that accompany obesity and the influence of lifestyle modification on these parameters.

Effects of a Single Dose of Exenatide on Appetite, Gut Hormones, and Glucose Homeostasis in Adults with Prader-Willi Syndrome

CONTEXT Prader-Willi syndrome (PWS) is associated with hyperphagia and obesity, without effective pharmacological treatment. Exenatide, recently developed for treatment of type 2 diabetes, induces appetite suppression and weight loss with common side effects. OBJECTIVE The objective of the study was to investigate the initial safety and effectiveness of exenatide in adult PWS subjects compared with obese controls (OBESE). DESIGN, SETTING, PATIENTS, AND INTERVENTION Eight PWS and 11 OBESE patients underwent standardized meal studies after a single sc injection of 10 μg exenatide or placebo in a single-blinded, crossover design. MAIN OUTCOME MEASURES Glucose, insulin, C-peptide, glucagon, peptide YY (PYY; total)/PYY (3-36), glucagon-like peptide-1, and ghrelin (total) were measured fasting and postprandially. Appetite and satiety were assessed by visual analog scales. Energy expenditure (EE) was measured by indirect calorimetry. Side effects were screened during and for 24 h after the meal. RESULTS PWS and OBESE patients were matched for gender, age, body mass index, and central/total body fat. In both groups, exenatide increased satiety and lowered glucose and insulin levels but increased insulin secretion rate. Side effects were absent in PWS but common in OBESE patients. During the meal, PYY (total) and ghrelin were elevated in PWS patients. Exenatide decreased PYY (total) and glucagon-like peptide-1, whereas ghrelin remained unchanged. Energy expenditure was unchanged by exenatide. CONCLUSIONS Our pilot study demonstrates that exenatide is well tolerated in PWS patients. It increases satiety independently of measured appetite hormones, exerting glucose lowering, and insulinotropic effects similarly in PWS and OBESE patients. Larger prospective studies should investigate whether chronic exenatide administration will reduce hyperphagia and overweight in PWS patients without side effects.

Characteristics of cardiac and vascular structure and function in Prader–Willi syndrome

Objective  Prader–Willi syndrome (PWS) is a genetic obesity syndrome characterized by hyperphagia, behavioural disturbance and intellectual disability. PWS appears to be associated with a high incidence of sudden death, suspected to be cardiopulmonary in origin. We therefore sought to provide an assessment of cardiac and vascular structure and function in patients with PWS.

Postprandial metabolism in adults with prader–willi syndrome

Individuals with Prader–Willi syndrome (PWS) are commonly restricted to 60‐75% of height‐appropriate calorie intake because they rapidly become obese on a normal diet. This study measured changes in energy expenditure, glucose and lipid homeostasis, and metabolic flexibility in response to a meal in PWS adults.

Postprandial cardiac autonomic function in Prader–Willi syndrome

Individuals with Prader–Willi syndrome (PWS) have a high cardiovascular risk, the mechanism of which is unclear. There may be dysfunction in the autonomic nervous system (ANS) in PWS.

Is dietary restraint deserving of a poor reputation

Results: A total of 104 CBIs participated in the 2013 survey and results compared against a similar survey in 2010. Geographic location was associated with higher population density. Duration of CBIs was short-term (median 3 yrs; range 0.2—21.0 yrs), delivered mostly by health departments and local governments. Median annual CBI funding had more than doubled since the 2010 survey, but average staffing had not increased. CBIs used at least two strategy types, with a preference for individual behaviour change strategies. Targeting children was less common (31%) compared to the 2010 survey (57%). Logic models and theory were used in planning, but there was low use of research evidence and existing prevention frameworks. Nearly all CBIs had an evaluation component (12% of budget), but dissemination was limited. Conclusion: This survey provides information on the scope and quality of the obesity prevention investment patterns in Australia. Geographic locations of CBIs are captured in detail by the COOPS interactive online map. To boost CBI quality, effectiveness and knowledge translation, further leadership and support systems are required to enable organisations to adopt upstream, evidenceinformed approaches; and for effective integration of CBIs into systems, policies and environments.