A single blinded, phase IV, adaptive randomised control trial to evaluate the safety of coadministration of seasonal influenza and COVID-19 vaccines (The FluVID study)

OBJECTIVES

We evaluated the frequency of moderate and severe adverse events following coadministration of seasonal influenza vaccine (SIV) versus placebo with COVID-19 vaccines among adults to support practice guidelines.

METHODS

FluVID is a participant-blinded, phase IV, randomised control trial. On the same day as the participant's scheduled COVID-19 vaccine, participants were randomised to receive SIV or saline placebo; those assigned placebo at visit one then received SIV a week later, and vice versa. Self-reported adverse events were collected daily for seven days following each visit. The primary endpoint was any solicited adverse event of at least moderate severity occurring up to seven days following receipt of SIV or placebo. This was modelled using a Bayesian logistic regression model. Analyses were performed by COVID-19 vaccine type and dose number.

RESULTS

Overall, 248 participants were enrolled; of these, 195 had received BNT162b2 and 53 had received mRNA1273 COVID-19 vaccines according to national guidelines. After randomisation, 119 were assigned to receive SIV and 129 were assigned to receive placebo at visit one. Adverse events were most frequently reported as mild (grade 1) in nature. Among 142 BNT162b2 booster dose one and 43 BNT162b2 booster dose two recipients, the posterior median risk difference for moderate/severe adverse events following SIV versus placebo was 13% (95% credible interval [CrI] -0.03 to 0.27) and 13% (95%CrI -0.37 to 0.12), respectively. Among 18 mRNA1273 booster dose one and 35 mRNA1273 booster dose two recipients, the posterior median risk difference of moderate/severe adverse events following influenza vaccine versus placebo was 6% (95%CrI -0.29 to 0.41) and -4% (95%CrI -0.30 to 0.23), respectively.

CONCLUSION

Adverse events following SIV and COVID-19 co-administration were generally mild and occurred with similar frequency to events following COVID-19 vaccine alone. We found no evidence to justify routine separation of SIV and COVID-19 vaccine doses.

CLINICAL TRIAL REGISTRATION

ACTRN12621001063808.

'Say no': a feasibility trial of a brief intervention to reduce instances of indulgent energy-intake episodes

The aim of this study is to examine the feasibility of a brief intervention to reduce instances of indulgent energy intake. Forty-five participants with a body mass index (BMI) ≥25 kg m-² were randomized to one of three groups for 8 weeks. The control group was asked to complete a questionnaire every 4 days, the self-monitoring group was given the same instructions but also asked to 'say no' to indulgences. The self-monitoring and feedback group was asked to do the same but in addition to send a photograph or description of that to which they had 'said no' and were then provided with feedback. All participants reported on indulgences for 7 days prospectively at baseline and 8-week follow-up. The follow-up rate was 80%; completion of questionnaires was 63% and 87 text messages were sent. The control group reduced their indulgences by 4.1 (SD 10.0), the self-monitoring group by 13.8 (SD 16.8) and self-monitoring and feedback group by 9.0 (SD 11.7) per week. All bar one, feasibility progression criteria were met and this was the return of the indulgence diaries during the intervention period. The study demonstrates the feasibility of a brief intervention to reduce the number of indulgences people ate. The progression criteria were met and areas of improvement are highlighted.

Liraglutide and cardiovascular outcomes in adults with overweight or obesity: A post hoc analysis from SCALE randomized controlled trials

The cardiovascular safety of liraglutide, a glucagon-like peptide-1 receptor agonist approved for weight management at a dose of 3.0 mg, was evaluated post hoc using data from 5908 participants in 5 randomized, double-blind, placebo-controlled clinical trials. Participants were randomized to liraglutide or a comparator group (placebo or orlistat). The objective was to evaluate whether cardiovascular risk was increased with liraglutide treatment. The primary composite outcome of this time-to-event analysis was the first occurrence of cardiovascular death, nonfatal myocardial infarction or nonfatal stroke. These cardiovascular events were adjudicated prospectively for three of the trials and retrospectively for two trials by an event adjudication committee. The primary outcome was analyzed using a Cox proportional hazards model, stratified by trial. With liraglutide 3.0 mg, 8 participants had positively adjudicated cardiovascular events (1.54 events/1000 person-years) compared to 10 participants in the comparators group (3.65 events/1000 person-years). The hazard ratio for liraglutide 3.0 mg compared to comparators was 0.42 (95% confidence interval, 0.17-1.08). In this analysis, liraglutide 3.0 mg treatment was not associated with excess cardiovascular risk. However, the wide confidence intervals and retrospective adjudication of events in two of the trials are limitations of the analysis.

Examining the association between depression and obesity during a weight management programme

The prevalence of depression in those with obesity is reported to be as high as double that in individuals of normal weight. There is potentially a bi-directional relationship between obesity and depression. Some research has suggested that depression results in weight gain and obesity, and other studies have suggested that those with obesity are more likely to develop depression at a later stage. The aim of this study was to investigate the association of depression symptoms with weight change over a 12-month study. Seventy participants undertook a 3-month lifestyle (diet and exercise) weight loss intervention, and were followed up as part of a 12-month study. Participants completed the Beck Depression Inventory-II (BDI-II) and had their body weight measured throughout the study. Baseline body mass index (BMI) of participants (mean ± standard deviation [SD]) was 31.1 ± 3.9 kg m^-2 , body weight was 89.4 ± 16.1 kg, and age was 45.4 ± 11.1 years; 63% of the cohort were female. The mean weight change from baseline to 3 months was -5.2% (±SD 4.3%), and from baseline to 12 months was -4.2% (±SD 6.1%). There was a significant decrease in BDI-II scores over the 12-month study, and a 1-unit decrease in BDI-II score was associated with a further decrease in body weight of -0.4%. The current study indicated that weight loss was associated with improvements in mood for non-clinically depressed individuals with obesity, and these improvements persisted during a period of 3-12 months of follow-up.

Investigating general medication prescription by general practitioners during a 12-month randomized controlled weight loss trial

Much healthcare expenditure is on pharmaceutical drugs. Expenditure on medications has increased both in absolute terms, and as a proportion of total health expenditure. No previous studies have investigated the prescribing costs by general practitioners when managing patients during a weight loss intervention. This study evaluated the medication costs by individual class during a 1-year study in which 268 participants were randomized to one of two weight loss programmes, either standard care (SC) as defined by national guidelines, or a commercial provider (Weight Watchers) (CP). The baseline body mass index of participants (mean ± standard deviation) was 32.0 ± 2.5 kg m^-2 , their body weight was 87.5 ± 11.8 kg, and age 47.4 ± 11.7 years. Weight loss for the SC and CP groups was -2.6 and -6.1 kg, respectively (between group difference; P < 0.0001). The greater weight loss in the CP group compared to SC was accompanied by larger reductions in waist circumference and fat mass. The CP group also had significantly greater improvements than SC in high-density lipoprotein cholesterol. Despite SC participants being prescribed and spending more on medications than the CP group with no better weight or metabolic outcomes, this was not of statistical significance. For both groups the highest proportion of prescriptions (≥30% of medications) was for control of risk factors for cardiovascular disease. In conclusion, this study indicates that obesity treatment via a shared care approach with a CP results in greater weight loss and some better clinical outcomes, but despite lower medication costs overall, this was not significant when compared to SC treatment.

Obesity, arterial function and arterial structure - a systematic review and meta-analysis

OBJECTIVE

Obesity is an established risk factor for cardiovascular disease. The mechanisms by which obesity affects cardiovascular risk have not been fully elucidated. This paper reports a comprehensive systematic review and meta-analysis on obesity and two key aspects of vascular health using gold-standard non-invasive measures - arterial endothelial function (brachial flow-mediated dilatation) and subclinical atherosclerosis (carotid intima-media thickness).

METHODS

Electronic searches for 'Obesity and flow-mediated dilatation' and 'Obesity and intima-media thickness' were performed using Ovid Medline and Embase databases. A meta-analysis was undertaken for brachial flow-mediated dilatation and carotid intima-media thickness to obtain pooled estimates for adults with obesity and those with healthy weight.

RESULTS

Of the 5,810 articles retrieved, 19 studies on flow-mediated dilatation and 19 studies on intima-media thickness were included. Meta-analysis demonstrated that obesity was associated with lower flow-mediated dilatation (-1.92 % [95% CI -2.92, -0.92], P = 0.0002) and greater carotid intima-media thickness (0.07 mm [95% CI 0.05, 0.08], P < 0.0001).

CONCLUSIONS

Obesity is associated with poorer arterial endothelial function and increased subclinical atherosclerosis, consistent with these aspects of vascular health at least partially contributing to the increased risk of cardiovascular events in adults with obesity. These estimated effect sizes will enable vascular health benefits in response to weight loss treatment to be put in greater perspective, both in the research setting and potentially also clinical practice.

Fast versus slow weight loss: development process and rationale behind the dietary interventions for the TEMPO Diet Trial

Objective and methods

Finding effective solutions to curb the obesity epidemic is a great global public health challenge. The need for long‐term follow‐up necessitates weight loss trials conducted in real‐world settings, outside the confines of tightly controlled laboratory or clinic conditions. Given the complexity of eating behaviour and the food supply, this makes the process of designing a practical dietary intervention that stands up to scientific rigor difficult. Detailed information about the dietary intervention itself, as well as the process of developing the final intervention and its underlying rationale, is rarely reported in scientific weight management publications but is valuable and essential for translating research into practice. Thus, this paper describes the design process and underlying rationale behind the dietary interventions in an exemplar weight loss trial – the TEMPO Diet Trial (Type of Energy Manipulation for Promoting optimal metabolic health and body composition in Obesity). This trial assesses the long‐term effects of fast versus slow weight loss on adiposity, fat free mass, muscle strength and bone density in women with obesity (body mass index 30–40 kg m⁻²) that are 45–65 years of age, postmenopausal and sedentary.

Results and conclusions

This paper is intended as a resource for researchers and/or clinicians to illustrate how theoretical values based on a hypothesis can be translated into a dietary weight loss intervention to be used in free‐living women of varying sizes.

A randomized controlled trial to determine the efficacy of a high carbohydrate and high protein ready-to-eat food product for weight loss

Incorporating meal replacements has been shown to produce a significantly greater weight loss than a conventional reduced calorie diet. Ready-to-eat conventional foods may also be effective in this role and provide additional benefit because of their palatability, acceptance and enjoyment and thus increase dietary compliance. This trial investigated the efficacy of a ready-to-eat food product (Vita-Weat biscuit) that is both high in carbohydrate and high in protein as part of a diet prescription for weight loss in an overweight and obese population group. A total of 76 participants were randomized to a 6-week weight loss intervention including the ready-to-eat food product (intervention group) or advice on the 'Australian Guide to Healthy Eating' (control group). Both groups lost approximately 2 kg weight which equated to a reduction in body mass index of 0.70 kg m(-2) . There was no significant difference in percentage weight loss from screening to 6 weeks between the two groups; mean difference for the intervention vs.

CONTROL GROUP

-0.20% (95% confidence interval: -0.96, 1.36); P = 0.73. Both diets were nutritionally matched and well-accepted over the 6-week period. This study shows that the inclusion of a ready-to-eat food product can be included as part of a dietary programme to achieve a clinically significant weight loss over a short period. This may have benefit when incorporated into an individual's meal plan intermittently to assist weight control. It also provides support for current public health nutritional guidelines as the participants in this study following such advice were also successful in achieving a clinically meaningful weight loss.

Do ketogenic diets really suppress appetite? A systematic review and meta-analysis

Very-low-energy diets (VLEDs) and ketogenic low-carbohydrate diets (KLCDs) are two dietary strategies that have been associated with a suppression of appetite. However, the results of clinical trials investigating the effect of ketogenic diets on appetite are inconsistent. To evaluate quantitatively the effect of ketogenic diets on subjective appetite ratings, we conducted a systematic literature search and meta-analysis of studies that assessed appetite with visual analogue scales before (in energy balance) and during (while in ketosis) adherence to VLED or KLCD. Individuals were less hungry and exhibited greater fullness/satiety while adhering to VLED, and individuals adhering to KLCD were less hungry and had a reduced desire to eat. Although these absolute changes in appetite were small, they occurred within the context of energy restriction, which is known to increase appetite in obese people. Thus, the clinical benefit of a ketogenic diet is in preventing an increase in appetite, despite weight loss, although individuals may indeed feel slightly less hungry (or more full or satisfied). Ketosis appears to provide a plausible explanation for this suppression of appetite. Future studies should investigate the minimum level of ketosis required to achieve appetite suppression during ketogenic weight loss diets, as this could enable inclusion of a greater variety of healthy carbohydrate-containing foods into the diet.

Changes in physical activity during a weight loss intervention and follow-up: a randomized controlled trial

Physical activity is an important component in weight loss treatment and weight maintenance. We evaluated the physical activity component of two weight loss programmes, either standard care (SC) as defined by national guidelines, or a commercial programme (CP; Weight Watchers) over the period of weight loss and follow-up. 772 adults (mean body mass index: 31.4 ± 2.6 kg m(-2)) were recruited by primary care practices in Australia, the United Kingdom, and Germany, and randomly assigned to 12 months SC, or the CP. They were then followed up at 24 months. Change in physical activity levels were assessed by the International Physical Activity Questionnaire (IPAQ)-short form, and pedometer recordings. Both groups reported increases in physical activity using the IPAQ from baseline to 12 months and 24 months (within groups P < 0.0001) and in pedometer steps from baseline to 12 months only (within groups P < 0.0001). Differences between groups with both methods of assessment were not significant. There was a significant difference in weight loss between the groups at 12 months favouring the CP group; however, this statistical difference was not maintained at 24 months. In conclusion, despite similar increases in reported activity, there were significant differences in weight loss and regain between groups. Therefore, greater weight loss seen with the CP is unlikely to be due to increases in physical activity. Trends in pedometer steps mirrored changes in weight over time more closely than the IPAQ; however, both assessment tools have limitations. Better activity assessment measures are needed to more accurately gauge changes in physical activity during weight loss interventions.

The challenge of a 2-year follow-up after intervention for weight loss in primary care

BACKGROUND

Many weight loss programmes show short-term success, but long-term data in larger studies are scarce, especially in community settings. Attrition is common and complicates the interpretation of long-term outcomes.

OBJECTIVE

To investigate 2-year outcomes and explore issues of attrition and missing data.

SUBJECTS

A total of 772 overweight and obese adults recruited by primary care practices in Australia, Germany and the UK and randomised to a 12-month weight loss intervention delivered in a commercial programme (CP) or in standard care (SC).

MEASUREMENT

Weight change from 0-24 and 12-24 months including measured weights only and measured and self-reported weights, using last observation carried forward (LOCF), baseline observation carried forward (BOCF), completers-only and missing-at-random (MAR) analyses.

RESULTS

A total of 203 participants completed the 24-month visit. Using measured weights only, there was a trend for greater 24-month weight loss in CP than in SC, but the difference was only statistically significant in the LOCF and BOCF analyses: LOCF: -4.14 vs -1.99 kg, difference adjusted for centre -2.08 kg, P<0.001; BOCF: -1.33 vs -0.74 kg, adjusted difference -0.60 kg, P=0.032; completers: -4.76 vs -2.99 kg, adjusted difference -1.53 kg, P=0.113; missing at random: -3.00 vs -1.94 kg, adjusted difference -1.04 kg, P=0.150. Both groups gained weight from 12-24 months and weight regain was significantly (P<0.001) greater for CP than for SC in all analysis approaches. Inclusion of self-reported weights from a further 138 participants did not change the interpretation of the findings.

CONCLUSION

Initial weight loss was poorly maintained during the no-intervention follow-up, but both groups did have lower weight over the 24 months. Attrition was high in both groups, and assumptions about missing data had considerable impact on the magnitude and statistical significance of treatment effects. It is vital that trials on weight loss interventions consider the plausibility of these differences in an analytical approach when interpreting research findings and comparing data between studies.

Weight loss improves reproductive outcomes in obese women undergoing fertility treatment: a randomized controlled trial

For women attempting pregnancy, obesity reduces fertility and is an independent risk factor for obstetric and neonatal complications. The aim of this evaluator-blinded, randomized controlled trial was to evaluate a weight loss intervention on pregnancy rates in obese women undertaking fertility treatment. Forty-nine obese women, aged ≤ 37 years, presenting for fertility treatment were randomized to either a 12-week intervention (n = 27) consisting of a very-low-energy diet for the initial 6 weeks followed by a hypocaloric diet, combined with a weekly group multidisciplinary programme; or a control group (n = 22) who received recommendations for weight loss and the same printed material as the intervention. Anthropometric and reproductive parameters were measured at baseline and at 12 weeks. The 22 women who completed the intervention had greater anthropometric changes (-6.6 ± 4.6 kg and -8.7 ± 5.6 cm vs. -1.6 ± 3.6 kg and -0.6 ± 6.3 cm) compared with the control group (n = 17; P < 0.001). The intervention group achieved a pregnancy rate of 48% compared with 14% (P = 0.007), took a mean two fertility treatment cycles to achieve each pregnancy compared with four in the control group (P = 0.002), and had a marked increase in the number of live births (44% vs. 14%; P = 0.02). A group weight loss programme, incorporating dietary, exercise and behavioural components, is associated with a significant improvement in pregnancy rates and live births in a group of obese women undergoing fertility treatment.

An intragastric balloon produces large weight losses in the absence of a change in ghrelin or peptide YY

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT?: The development of obesity is a multi-factorial process that results in an alteration in the neuroendocrine hormones that help regulate appetite and body weight. Weight loss has been shown to alter this neuroendocrine balance so as to promote weight regain. An intragastric balloon is an effective method to achieve significant weight loss in obese patients and is well suited for those patients who are looking for an alternative to lifestyle modification alone, and those who are not ready or suitable for surgical intervention. Limited research has shown that the weight loss achieved with an intragastric balloon is mediated by altered secretion of the hormones that regulate appetite and weight. WHAT DOES THIS STUDY ADD?: There are currently limited data on the effects of intragastric balloons on appetite and weight-related hormones. In the current study, we have investigated a broad range of gut hormones and adipokines and their response to weight loss induced by differing methods, and the subsequent effect this may have on weight regain. This is an important research area as novel therapies and long-term strategies are needed to counteract the unfavourable changes to the neuroendocrine control of appetite and satiety associated with diet-induced weight loss. This study aims to determine the effect of weight loss achieved with different methods on fasting levels of appetite hormones. Sixty-six obese adults with metabolic syndrome were randomized to intragastric balloon (IGB) for 6 months, with a 12-month behavioural modification programme (IGB group, 'IGBG') or a 12-month behavioural modification programme alone (control group, 'CG'). Anthropometric assessments and blood samples were taken every 3 months and total ghrelin, peptide YY (PYY), adiponectin and leptin were measured. Significant weight-loss differences favouring the IGBG were evident between groups at all time points. Ghrelin increased when the IGB was in situ (+39.3 pmol L(-1) vs. baseline) and returned to baseline after its removal (-34.7 pmol L(-1) ). Adiponectin and PYY levels remained stable in the IGBG, with transient increases noted in the CG. There were no significant between-group differences for ghrelin, PYY or adiponectin. In the IGBG, despite a decrease in leptin at 6 months (-11.7 ng mL(-1) ), levels increased to baseline after IGB removal (-3.7 ng mL(-1) ). In summary, weight loss associated with the IGB did not alter fasting levels of PYY or adiponectin. There was a return of ghrelin and leptin levels to baseline values after IGB removal. No compensatory rise in ghrelin was evident in either group 12 months after initial weight reduction, suggesting that such treatment strategies may lead to better long-term sustainable weight loss.

Comparability and utility of body composition measurement vs. anthropometric measurement for assessing obesity related health risks in Korean men

BACKGROUND

Obesity is commonly assessed by body mass index (BMI) of which limitations come from an inability to distinguish body fat mass from lean mass. Several anthropometric measurements, including BMI, waist circumference, waist-to-height ratio and waist-to-hip ratio have been used to predict metabolic syndrome. The purpose of this study was to evaluate the utility of FMI or BF% combined with previous known anthropometric indices to assess the risk of metabolic syndrome in clinical practice.

METHODS

In 5534 men visiting a hospital for health check-ups, blood tests, anthropometric measurements and body composition analysis using BIA were performed. Logistic regression analysis was performed to compare the odds ratios for metabolic syndrome and each component of metabolic syndrome among BMI, waist-to-height ratio, waist-to-hip ratio, FMI and BF%. The area under the curve (AUC) of the receiver operating characteristic curve (ROC) for metabolic syndrome was compared between several measurements. The net reclassification improvement with integrated discrimination improvement was used for assessing value of body composition measurement.

RESULTS

The adjusted odds ratios of metabolic syndrome was 1.80 (95% CI, 1.71-1.89) for FMI and 1.15 (95% CI, 1.13-1.17) for BF%. Odds ratio of each metabolic component was highest for FMI among several anthropometric and body composition measurements. AUCs using the ROC curve for metabolic syndrome was highest for waist-to-height ratio, 0.823 (95% CI, 0.808-0.837) by National Cholesterol Education Program criteria. FMI caused a mild increase in integrated discrimination improvement when combined with waist-to-height ratio.

CONCLUSIONS

Waist-to-height ratio seems to be the best screening tool for evaluating metabolic syndrome in Korean men, and adding FMI could result in a modest increase in integrated discrimination improvement.

Relationship between HbA1c levels and risk of cardiovascular adverse outcomes and all-cause mortality in overweight and obese cardiovascular high-risk women and men with type 2 diabetes

AIMS/HYPOTHESIS

The optimal HbA(1c) concentration for prevention of macrovascular complications and deaths in obese cardiovascular high-risk patients with type 2 diabetes remains to be established and was therefore studied in this post hoc analysis of the Sibutramine Cardiovascular OUTcomes (SCOUT) trial, which enrolled overweight and obese patients with type 2 diabetes and/or cardiovascular disease.

METHODS

HRs for meeting the primary endpoint (nonfatal myocardial infarction, nonfatal stroke, resuscitated cardiac arrest or cardiovascular death) and all-cause mortality were analysed using Cox regression models.

RESULTS

Of 8,252 patients with type 2 diabetes included in SCOUT, 7,479 had measurements of HbA(1c) available at baseline (i.e. study randomisation). Median age was 62 years (range 51-86 years), median BMI was 34.0 kg/m(2) (24.8-65.1 kg/m(2)) and 44% were women. The median HbA(1c) concentration was 7.2% (3.8-15.9%) (55 mmol/l [18-150 mmol/l]) and median diabetes duration was 7 years (0-57 years). For each 1 percentage point HbA(1c) increase, the adjusted HR for the primary endpoint was 1.17 (95% CI 1.11, 1.23); no differential sex effect was observed (p = 0.12 for interaction). In contrast, the risk of all-cause mortality was found to be greater in women than in men: HR 1.22 (1.10, 1.34) vs 1.12 (1.04, 1.20) for each 1 percentage point HbA(1c) increase (p = 0.02 for interaction). There was no evidence of increased risk associated with HbA(1c) ≤ 6.4% (≤ 46 mmol/l). Glucose-lowering treatment regimens, diabetes duration or a history of cardiovascular disease did not modify the associations.

CONCLUSIONS/INTERPRETATION

In overweight, cardiovascular high-risk patients with type 2 diabetes, increasing HbA(1c) concentrations were associated with increasing risks of cardiovascular adverse outcomes and all-cause mortality.

Maintained intentional weight loss reduces cardiovascular outcomes: results from the Sibutramine Cardiovascular OUTcomes (SCOUT) trial

AIM

The Sibutramine Cardiovascular OUTcomes trial showed that sibutramine produced greater mean weight loss than placebo but increased cardiovascular morbidity but not mortality. The relationship between 12-month weight loss and subsequent cardiovascular outcomes is explored.

METHODS

Overweight/obese subjects (N = 10 744), ≥55 years with cardiovascular disease and/or type 2 diabetes mellitus, received sibutramine plus weight management during a 6-week Lead-in Period before randomization to continue sibutramine (N = 4906) or to receive placebo (N = 4898). The primary endpoint was the time from randomization to first occurrence of a primary outcome event (non-fatal myocardial infarction, non-fatal stroke, resuscitated cardiac arrest or cardiovascular death).

RESULTS

For the total population, mean weight change during Lead-in Period (sibutramine) was -2.54 kg. Post-randomization, mean total weight change to Month 12 was -4.18 kg (sibutramine) or -1.87 kg (placebo). Degree of weight loss during Lead-in Period or through Month 12 was associated with a progressive reduction in risk for the total population in primary outcome events and cardiovascular mortality over the 5-year assessment. Although more events occurred in the randomized sibutramine group, on an average, a modest weight loss of approximately 3 kg achieved in the Lead-in Period appeared to offset this increased event rate. Moderate weight loss (3-10 kg) reduced cardiovascular deaths in those with severe, moderate or mild cardiovascular disease.

CONCLUSIONS

Modest weight loss over short-term (6 weeks) and longer-term (6-12 months) periods is associated with reduction in subsequent cardiovascular mortality for the following 4-5 years even in those with pre-existing cardiovascular disease. While the sibutramine group experienced more primary outcome events than the placebo group, greater weight loss reduced overall risk of these occurring in both groups.

Overview of endocrinopathies associated with β-thalassaemia major

BACKGROUND

  Thalassaemia major is a common and serious medical problem worldwide that is associated with a range of complications, including effects on multiple endocrine pathways. Minimizing or preventing comorbidities is important for these individuals who need life-long multidisciplinary care and treatment. However, there are limited overviews of the endocrine complications associated with this illness, nor any consensus regarding management guidelines.

METHOD

  A retrospective cohort analysis of β-thalassaemia patients attending an ambulatory transfusion clinic at Royal Prince Alfred Hospital was conducted from June 2008.

RESULTS

  All of our subjects (n=29) had at least one endocrinopathy present with 16 patients (55%) having three or more (≥3) endocrinopathies. Hypogonadism was the most prevalent followed by osteoporosis and growth failure (less than 3rd centile) with a frequency of 16/29 (55%), 14/29 (48%) and 10/29 (35%) patients respectively. Those with more endocrinopathies (≥3) had a longer duration of transfusion therapy when compared with those with fewer endocrinopathies.

CONCLUSION

  A summary of our clinical guidelines, which have been used to monitor and manage these complications, is presented along with a discussion on the results and pathophysiology of the associated endocrinopathies.

Coordinated improvement in glucose tolerance, liver steatosis and obesity-associated inflammation by cannabinoid 1 receptor antagonism in fat Aussie mice

OBJECTIVE

Fat Aussie mice (foz/foz) are morbidly obese, glucose intolerant and have liver steatosis that develops into steatohepatitis on a high-fat diet. The cannabinoid 1 receptor (CB1) antagonist SR141716 has been shown to improve obesity-associated metabolic complications in humans and rodent models. The aim of this study was to assess the effect of SR141716 in foz/foz mice.

DESIGN

Male wildtype (WT) and foz/foz mice were fed a chow or high-fat diet (45% saturated fat). Vehicle or SR141716 (10 mg kg(-1) per day) was administered in jelly once daily for 4 weeks from 4 months of age.

RESULTS

Foz/foz mice were obese but had less epididymal adipose tissue mass than fat-fed WT mice despite being significantly heavier. Liver weight was increased by twofold in foz/foz compared with WT mice and showed significant steatogenesis associated with impaired liver function. Foz/foz and fat-fed WT mice were glucose intolerant as determined by oral glucose tolerance test. In chow-fed foz/foz mice, SR141716 reduced body weight, liver weight, reversed hepatosteatosis and glucose intolerance. Subcutaneous white adipose tissue gene expression of the macrophage-specific marker Cd68 reflected the improvements in the metabolic status by SR141716 in these mice.

CONCLUSION

The results are consistent with the hypothesis that foz/foz mice have defective lipid metabolism, are unable to adequately store fat in adipose tissue but instead sequester fat ectopically in other metabolic tissues (liver) leading to insulin resistance and hepatic steatosis associated with inflammation. Our findings suggest that SR141716 can improve liver lipid metabolism in foz/foz mice in line with improved insulin sensitivity and adipose tissue inflammation.

Weight and perceptions of body image in women and men in a Sydney sample

Using a modification of the distorting camera technique, 50 obese women (body mass index (BMI; kg/m2 35.1 +/- 1.1), 40 obese men (BMI 38.2 +/- 1.5) and their respective normal weight controls estimated their body size. The obese women, control women and obese men overestimated their body size, whilst control weight men were accurate. The control men were satisfied with their body size, control women less so and the obese were unsatisfied. Whilst the control women considered themselves overweight (BMI 26.7 +/- 0.8 compared to actual BMI 23.1 +/- 0.5, P less than 0.001) their preferred and actual body sizes were identical. There were no differences between obese subjects and controls in the sizes they considered healthy and attractive. The accepted normal size range for a woman was lower than that accepted for men. Older men (both obese and normal weight) accepted larger sizes for women than younger men. These results show that the obese overestimated their body size and supports the notion that there is social pressure on women to strive towards a slimmer ideal, whilst overweight men are more accepted.

Weight and blood pressure response to weight management and sibutramine in diabetic and non-diabetic high-risk patients: an analysis from the 6-week lead-in period of the sibutramine cardiovascular outcomes (SCOUT) trial

OBJECTIVE

To assess treatment responses to sibutramine and weight management in diabetic patients during the lead-in period of the Sibutramine Cardiovascular OUTcomes (SCOUT) trial.

METHODS

SCOUT is an ongoing, prospective, randomized, double-blind, placebo-controlled outcome trial in cardiovascular high-risk overweight/obese patients. A total of 10 742 patients received single-blind sibutramine and individualized weight management during the 6-week lead-in period; 84% had a history of type 2 diabetes mellitus and additional co-morbidities. Post-hoc analyses assessed anthropomorphic and vital sign responses between patients with and without diabetes.

RESULTS

Concomitant antidiabetic medication use was reported by 86% of the diabetic patients (approximately 30% required insulin-alone or in combination). Body weight and waist circumference decreased in diabetic patients: median 2.1 kg; 2.0 cm (both men and women); for those on insulin: 1.9 kg; 1.5/2.0 cm (men/women); without insulin: 2.3 kg; 2.0 cm (both men and women); blood pressure (BP) was also reduced (median systolic/diastolic 3.5/1.0 mmHg) with larger reductions in diabetic patients who were hypertensive and/or lost the most weight (>5%). In diabetic patients who entered with BP at target (<130/<85 mmHg) but did not lose weight (N = 245), increases of 3.5/2.0 mmHg were observed. Non-diabetic patients had greater weight losses (2.5 kg) but smaller reductions in BP (systolic/diastolic -2.5/-0.5 mmHg). Pulse rate increases were less in diabetic vs. non-diabetic patients (1.5 vs. 2.0 bpm).

CONCLUSION

In these high-risk diabetic patients, sibutramine and lifestyle modifications for 6 weeks resulted in small, but clinically relevant, median reductions in body weight, waist circumference and BP. A small median increase in pulse rate was recorded.

The use of motivational enhancement strategies for the maintenance of weight loss among obese individuals: a preliminary investigation

AIM

To investigate the efficacy of motivational enhancement strategies integrated within a standard lifestyle modification program for the maintenance of weight loss and improved psychosocial functioning of obese adults.

METHODS

Twenty-two obese adults completed 20 sessions of a motivationally informed cognitive behavioural treatment for weight loss and maintenance. Treatment outcome measures included anthropometrics, obesity-specific quality of life, impulsive eating tendencies, body dissatisfaction, mood disturbance and maladaptive cognitions.

RESULTS

At post-treatment, there was a significant decrease in body weight (123.04 +/- 22.06 vs. 116.84 +/- 23.53, p < 0.001) with no significant change by the 12-month follow-up. Patients also reported significant improvements in obesity-related quality of life, impulsive eating tendencies, body dissatisfaction and maladaptive cognitions at post-treatment that were maintained at the 1-year follow-up.

CONCLUSIONS

The implementation of motivational enhancement strategies within a cognitive behavioural program results in sustained weight loss that compares favourably to previous lifestyle modification programs.

Blood pressure changes associated with sibutramine and weight management - an analysis from the 6-week lead-in period of the sibutramine cardiovascular outcomes trial (SCOUT)

OBJECTIVE

To explore vital sign changes among patient subgroups during the 6-week lead-in period of the sibutramine cardiovascular outcomes (SCOUT) trial.

METHODS

SCOUT is an ongoing, double-blind, randomized, placebo-controlled outcome trial in overweight/obese patients at high risk of a cardiovascular event. During the 6-week lead-in period, 10,742 patients received sibutramine and weight management. Vital sign changes were assessed post hoc by initial blood pressure (mmHg) categorized as normal (<130/<85), high-normal (130 to <140/85 to <90) or hypertensive (>or=140/>or=90); weight change categories (weight gain/no weight change, >0 to 2.5% weight loss, >2.5 to 5% weight loss and >5% weight loss) and current antihypertensive medication class use (none, one, or two or more). To assess the impact of sibutramine on blood pressure and pulse rate, only patients (N = 10,025) who reported no change in the class of antihypertensive medication used and who did not report an increase in antihypertensive medication use were analysed.

RESULTS

At entry, approximately 50% of patients were hypertensive and 26% were high-normal. In hypertensive patients, blood pressure changes (mmHg) decreased by median [5th, 95th percentile] of -6.5 systolic [-27.0, 8.0] and -2.0 diastolic [-15.0, 8.0] (p < 0.001). Hypertensive patients with no weight loss or with weight gain had median decreases of -3.5 systolic [-26.0, 10.0] and -1.5 diastolic [-16.0, 9.0] (p < 0.001). Normotensive patients had median increases of 1.5 systolic [-15.0, 19.5] and 1.0 diastolic [-10.5, 13.0] (p < 0.001) attenuated with increasing weight loss. Approximately 43% of patients initially categorized as hypertensive had a lower blood pressure category at end-point. Concomitant antihypertensive medication classes did not affect blood pressure reductions. Pulse rates were uniformly elevated (median 1-4 bpm, p < 0.001) across blood pressure and weight change categories.

CONCLUSIONS

In hypertensive patients (>or=140/>or=90), blood pressure decreases were observed during 6-week treatment with sibutramine even when body weight was unchanged. In patients with normal blood pressure (<130/<85), weight loss of >5% induced decreases in systolic blood pressure; otherwise, small increases were observed. Small pulse rate increases were observed regardless of blood pressure or weight change status.

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.

METHODS

Preclinical markers of vasculopathy in resistance vessels and conduit arteries and left ventricular structure and function were assessed in 39 obese subjects (BMI > 30 kg/m(2)) and 11 healthy weight controls. The influence of serum on cellular adhesion molecule (CAM) expression on human endothelial cells was studied ex vivo in a subgroup of 13 obese and nine healthy weight subjects. These analyses were repeated in all 17 of the obese subjects who complied with 4-9 months of lifestyle modification treatment (six with weight loss >5% and 11 with weight loss <5%).

RESULTS

Compared with healthy weight controls, obese subjects had decreased peak hyperaemic forearm blood flow (p = 0.015), increased carotid intima-media thickness (p = 0.009), increased left ventricular wall thickness and volume and evidence of systolic and diastolic dysfunction as assessed using tissue Doppler imaging (S', p = 0.09; E'/A', p = 0.02), and serum from obese subjects increased the intercellular CAM-1 expression on human endothelial cells (p = 0.009). However, arterial endothelial function assessed by flow-mediated dilatation was not altered (p = 0.99). Lifestyle modification treatment resulted in potentially beneficial changes in fibrinogen (p = 0.003), HDL cholesterol (p = 0.05) and soluble vascular CAM-1 (p = 0.06). In subjects with weight loss greater than 5% of body weight, there was also a decrease in low-level inflammation (high-sensitivity C-reactive protein, p = 0.05), lipid peroxidation (thiobarbituric acid-reactive substances, p = 0.05) and triglycerides (p = 0.07).

CONCLUSIONS

Obesity is associated with widespread alterations in cardiac and vascular structure and function. Moderate short-term weight loss by lifestyle modification results in some beneficial changes in serum profile; however, these are not accompanied by significant alterations to either cardiac or vascular structure and function.

Leptin secretion is related to glucose-derived lipogenesis in isolated adipocytes

OBJECTIVE

Leptin secretion in rats is regulated acutely by nutritional state. Insulin plays an important role in this acute nutritional regulation both directly and indirectly through effects on glucose metabolism. The aim of this study was to investigate if the fasting-induced suppression of leptin secretion was reversed by incubation under conditions mimicking nutritional repletion.

DESIGN

Leptin secretion and glucose metabolism were measured following incubation with glucose and insulin in adipocytes isolated from fed and fasted rats.

RESULTS

Leptin secretion was stimulated by incubation with glucose and insulin in adipocytes isolated from fed but not from fasted rats as was glucose flux through oxidative and lipogenic pathways. Ob expression and intracellular leptin content were decreased in adipocytes isolated from fasted rats throughout the whole incubation period. Suppression of glucose metabolism with cytochalasin B was accompanied by suppression of leptin secretion. The amount of leptin secretion correlated with the glucose incorporated into lipid under insulin-stimulated conditions.

CONCLUSIONS

It is proposed that glucose incorporation into lipid, at least during insulin-stimulated conditions, reflects the metabolic status of the adipocyte and may be a more important regulator of leptin production and secretion than circulating glucose or insulin levels.

Effect of orlistat on cardiovascular disease risk in obese adults

AIM

The aim of this study is to compare the effect of orlistat vs. placebo on the predicted 10-year cardiovascular disease (CVD) risk in obese people with one or more cardiovascular risk factors treated for 12 months, in conjunction with a fat-reduced, but otherwise ad libitum, diet.

METHODS

A double-blind, randomized, placebo-controlled, parallel study was performed in conjunction with a fat-reduced diet and physical activity advice for 1 year. Participants (n = 339) from eight centres in Australia and New Zealand were randomized to either orlistat (120 mg) three times daily (n = 104 women, 66 men; mean +/- s.d. age = 52.0 +/- 7.5 years, body mass index (BMI) = 37.6 +/- 5.1 kg/m(2)) or placebo three times daily (n = 89 women, 80 men; age = 52.5 +/- 7.4 years, BMI = 38.0 +/- 4.9 kg/m(2)). The primary efficacy criterion was the 10-year risk of developing CVD calculated from the Framingham equation. Secondary efficacy criteria were body weight, waist circumference, blood pressure and serum concentrations of triglycerides, cholesterol (total, LDL and HDL), glucose, insulin and glycated haemoglobin and quality of life.

RESULTS

There was no difference in the change in 10-year CVD risk between orlistat and placebo groups over 1 year. The orlistat group, however, had significant favourable changes in many of the individual CVD risk factors (total cholesterol, LDL-cholesterol, glucose, glycated haemoglobin, insulin, body weight and waist circumference) and one of the domains of quality of life measured by means of the SF-36 questionnaire (vitality), compared to the placebo group. Significant reductions in medication use for hypertension and diabetes were observed in the orlistat group, compared to those in placebo, but there were no significant differences in medication use for blood lipids.

CONCLUSIONS

Orlistat may have reduced CVD risk, as judged by the favourable changes in individual risk factors and reductions in medication use, but the method used in order to measure absolute CVD risk in this study (Framingham CVD equation) was not sensitive enough to detect the changes in this relatively low-risk group (approximately 10% of risk of a CVD event over 10 years).

Insulin determines leptin responses during a glucose challenge in fed and fasted rats

OBJECTIVE

Leptin secretion has been shown to respond acutely to changes in blood glucose and insulin. Nutritional state also has a marked effect on both the level of circulating leptin protein and leptin gene expression. The aim of this study was to assess whether the prior nutritional state altered the leptin secretory response to an acute glucose challenge, and to determine potential mechanisms.

DESIGN

Male fed or fasted rats (200-250 g) were administered a single intravenous glucose bolus (1, 4 or 7 g/kg). The serum leptin, glucose, insulin and free fatty acid responses were studied over the following 5 h. The level of leptin gene expression and leptin protein was then determined in the epididymal fat pads, and in fed and fasted untreated rats for basal comparison.

RESULTS

Leptin secretion in response to glucose was suppressed in fasted rats following all glucose doses. The total leptin response was correlated with the total insulin response in all conditions (r = 0.85) and with the glucose response in fed rats (r = 0.69). Both leptin gene expression and leptin protein content were lower in basal fasted rats. Leptin gene expression and leptin protein content still remained lower 5 h following a glucose bolus but there was partial reversal of the effects of fasting following the 7 g/kg glucose dose.

CONCLUSIONS

Leptin secretion in response to an intravenous glucose bolus was determined by the insulin response and was significantly suppressed in fasted compared to fed rats. In addition to differences in the total insulin response of the animals, lower leptin responses may be facilitated by lower levels of both leptin gene mRNA and pre-existing leptin protein in epididymal adipose tissue of fasted rats.

Plasma leptin is associated with insulin resistance independent of age, body mass index, fat mass, lipids, and pubertal development in nondiabetic adolescents

OBJECTIVE

The rising epidemic worldwide in overweight and obese children requires urgent attention. Leptin has been found to be associated with body weight control and possibly affects insulin sensitivity. Since insulin resistance is associated with obesity in adults and possibly in adolescents, we set out to investigate the association of plasma leptin level with various anthropometric indices, body fat mass (FM), lipids, and insulin resistance (IR) index in nondiabetic adolescents.

DESIGN

A cross-sectional study from three high schools in Taipei City in Taiwan.

SUBJECTS

A total of 402 nondiabetic subjects (162 boys and 240 girls; age range, 10-19 y; mean age, 15.8+/-1.9 y, and mean body mass index (BMI), 24.8+/-4.6 kg/m(2)) were recruited.

MEASUREMENTS

The fasting plasma leptin, plasma glucose, insulin, lipids, and anthropometric indices including height, weight, waist (WC) and hip circumferences, and waist-to-hip ratio (WHR) were examined. Total body FM and percentage body fat (FM%) were obtained from dual-energy X-ray absorptiometry. The homeostasis model was applied to estimate the degree of IR.

RESULTS

The plasma leptin levels were significantly higher in girls (17.45+/-10.13 ng/ml) than boys (8.81+/-6.71 ng/ml, P<0.001). The plasma leptin levels were positively correlated to BMI, WC, WHR, FM, FM%, and triglycerides (TG). The IR index was positively correlated to BMI, WC, WHR, FM, FM%, TG, and leptin. Using the multivariate linear regression models, we found that plasma leptin remains significantly associated with IR index even after adjusting for age, gender, BMI, FM, WC, Tanner stage, and TG.

CONCLUSION

Plasma leptin was associated with IR index independent of age, gender, BMI, FM, WC, Tanner stage, and TG. Plasma leptin levels in adolescents could be a predictor for the development of the metabolic syndrome disorders and cardiovascular diseases.

Dietary modulation of circulating leptin levels: site-specific changes in fat deposition and ob mRNA expression

In order to study the effects of diet on fat distribution, circulating leptin levels and ob mRNA expression, diets of different macronutrient composition were fed to lean mice and gold thioglucose-obese mice. A high-fat diet and 2 high-carbohydrate diets, one containing mostly high-glycaemic-index starch and the other containing low-glycaemic-index starch were fed ad libitum for 10 weeks and were compared to standard laboratory chow. Weight gain was attenuated by feeding low-glycaemic-index starch in all mice and by feeding a high-fat diet in lean mice. Reduced adiposity was seen in lean mice fed low-glycaemic-index starch, whereas increased adiposity was seen in both lean and obese mice fed on the high-fat diet. Circulating leptin levels, when corrected for adiposity, were decreased in all mice fed either the high-fat diet or the low-GI diet. In epididymal fat pads, decreased ob mRNA expression was seen after both high-fat and high-glycaemic-index starch feeding. These results show that diet macronutrient composition contributes to the variability of circulating leptin levels by the combined effects of diet on fat distribution and on site-specific changes in ob mRNA expression.

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/m(2)) and 138 obese (BMI 37.7+/-5.8 kg/m(2)) 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.

G-protein beta3 subunit gene splice variant in obesity and overweight

OBJECTIVE

To determine whether the C825T polymorphism of the G-protein beta3 subunit gene (GNB3) is associated with overweight and obesity. This polymorphism leads to a splice variant (Gbeta3-s) with higher activity and very strong association with essential hypertension.

DESIGN

A cross-sectional case-control study.

SUBJECTS

The sets of affected and control British/European Caucasian subjects used were: (i) an obesity clinic group most of whom had "morbid obesity" (mean body mass index (BMI) for group=43+/-8 kg/m(2)) and non-obese controls (BMI< or =30); (ii) a group of overweight/obese healthy normotensive community volunteers (BMI>25; mean 29+/-5) and controls (BMI< or =25; mean 23+/-1); (iii) a group of overweight/obese hypertensive patients (BMI>25; mean 30+/-4) and lean hypertensive controls (BMI< or =25; mean=23+/-2).

MEASUREMENTS

BMI, blood pressure, serum lipids, alleles of GNB3 polymorphism.

RESULTS

Compared with control, frequency of the T allele in obese subjects was higher by 12% in (i), 17% in (ii) and 28% in (iii), but the differences were not statistically significant. Slight tracking of the T allele with elevation in BMI was, however, observed, in the obesity clinic group (P=0.018).

CONCLUSION

The C825T splice variant of GNB3 makes little if any contribution to obesity in the groups we tested.

In vivo and in vitro suppression by leptin of glucose-stimulated insulin hypersecretion in high glucose-fed rats

OBJECTIVES

Chronic feeding to rats of high glycaemic index (GI) diets results in the hypersecretion of insulin in response to an i.v. glucose load. The first aim of this study was to see if this exaggerated insulin response was accompanied by a hypersensitivity to glucose stimulation in isolated islets in vitro. The second aim was to see if the adipocyte factor, leptin, was able to alter insulin secretion in this model both in vivo and in vitro.

DESIGN AND METHODS

Rats were fed for 6 weeks either a high GI diet in which the carbohydrate component was mostly glucose (GLUC diet) or a low GI diet containing mostly amylose (AMOSE diet). Rats then underwent an i.v. glucose tolerance test (ivGTT) (1g/kg) with and without a prior infusion of leptin (133 microg/kg perh). Islets were then isolated from these rats and basal and glucose-stimulated insulin secretion (GSIS) measured in both the absence and presence (100ng/ml) of leptin.

RESULTS AND CONCLUSIONS

Peak insulin response during the ivGTT was 3-fold greater in GLUC rats (P<0.001). Leptin had no effect on AMOSE rat insulin response but lowered the GLUC rat response to AMOSE rat levels. In vitro, basal insulin secretion was 4-fold greater in GLUC rats (P<0.05). At 20mmol/l glucose, there was no further increase in insulin secretion in GLUC rats but a 2-fold increase in AMOSE rats. Leptin had no effect on basal insulin secretion or GSIS in AMOSE rats but reduced basal insulin secretion and GSIS in GLUC rats. These results show insulin hypersecretion in high GI-fed rats may be reduced by leptin.

Leptin has acute effects on glucose and lipid metabolism in both lean and gold thioglucose-obese mice

Leptin is reported to have effects in peripheral tissues that are independent of its central effects on food intake and body weight. In this study, the acute effects of a single dose of recombinant mouse leptin on lipid and glucose metabolism in lean and gold thioglucose-injected obese mice were examined. Changes were measured 2 h after leptin injection. In lean mice, liver and white adipose tissue (WAT) lipogenesis was inhibited. The activity of the pyruvate dehydrogenase complex (PDHCa), the rate-determining step for glucose oxidation, was reduced in heart, liver, quadriceps muscle, and both brown and white adipose tissues. Muscle and liver glycogen and liver triglyceride (TG) content was unchanged, but muscle TG was decreased. In obese mice, liver and WAT lipogenesis was inhibited and PDHCa reduced in heart and quadriceps muscle. Muscle and liver glycogen was decreased but not TG. Serum insulin was reduced in obese but not lean mice. These results are consistent with a role for leptin in the maintenance of steady-state energy stores by decreasing lipid synthesis and increasing fat mobilization, with decreased glucose oxidation occurring as a result of increased fatty acid oxidation.

Chronic administration of BRL 26830A for 9 weeks improves insulin sensitivity but does not prevent weight gain in gold-thioglucose obese mice

BRL 26830A, a beta adrenoceptor agonist, has been shown to have antiobesity and antidiabetic properties in rodents. The aim of this study was to study the effects of chronic BRL 26830A treatment (20 mg/kg/day for 9 weeks) on weight gain and the development of insulin resistance in gold-thioglucose-injected mice (GTG). BRL 26830A slowed the rate of weight gain in GTG such that mice weighed significantly less between 2 w and 7 w of treatment. However, at the time of sacrifice (9 w), there was no difference in body weight between treated and untreated GTG. The obesity-induced reduction in lipogenesis in brown adipose tissue (BAT) was increased 9 fold to greater than CON levels. However, weight and fatty acid (FA) content of BAT were reduced, suggesting increased lipid turnover and thermogenesis. Lipogenesis, FA content and fat pad weight were unchanged in white adipose tissue (WAT) and decreased in liver of GTG. Glucose tolerance was improved in both CON and GTG. Hyperglycemia, hyperinsulinemia and changes in cardiac and hepatic glucose oxidation as indicated by PDHC activity were normalized. Serum triglycerides and non-esterified fatty acids were reduced. Thus, chronic BRL 26830A treatment prevented the development of insulin resistance and attenuated weight gain, but did not prevent the development of obesity in this model.

Plasma insulin rise precedes rise in ob mRNA expression and plasma leptin in gold thioglucose-obese mice

Circulating leptin levels are strongly related to the degree of adiposity, with hyperleptinemia being associated with hyperinsulinemia. In the gold thioglucose-injected mouse (GTG), hyperinsulinemia is an early abnormality in the development of insulin resistance and obesity. In this study, hyperinsulinemia occurred 1 wk post-GTG [GTG, 199 +/- 43; age-matched controls (CON), 53 +/- 5 microU/ml; P < 0.001], with leptin levels not rising until 2 wk post-GTG (CON, 3.2 +/- 0.3; GTG, 9.9 +/- 1.7 ng/ml; P < 0.001) in parallel with increases in the size of different fat pads and increased expression of ob mRNA. The ratio of serum leptin to fat pad weight was significantly higher in GTG mice 12 wk postinjection. Starvation-induced reductions in serum leptin (50%), glucose (50%), and insulin (74%) were greater than decreases in fat pad weight (18%). Adrenalectomy decreased both adiposity and serum leptin within 1 wk in both CON and GTG and altered the serum leptin level-to-fat pad weight ratio in CON. Thus hyperinsulinemia preceded increased ob expression and hyperleptinemia, which occurred in parallel with increasing adiposity, consistent with the role of leptin as an indicator of energy supplies. Changes in hormonal and nutritional status may modify this relationship.

Muscle fibre type composition in infant and adult populations and relationships with obesity

OBJECTIVES

To investigate the fibre type composition of skeletal muscle in infants and young children and to compare the findings to an adult population. To relate the fibre type profile of skeletal muscle in adults to measures of adiposity.

DESIGN

Cross-sectional studies of skeletal muscle fibre composition in infants and adults with measures of adiposity in the adults.

SUBJECTS

21 healthy infants and young children (age: 3-21 months) and 40 healthy adult Australian Caucasians (age: 26-62 y; BMI: 18-48 kg/m2).

MEASUREMENTS

Skeletal muscle fibre type composition (by myosin ATPase method) and relative body fatness (BMI, waist circumference and waist/hip ratio (WHR)).

RESULTS

Infants and young children had significantly lesser proportions of glycolytic Type 2b fibres (6.2 +/- 1.1%; range 0.3-18.9%) compared with adults (20.5 +/- 1.6%; range 4.9-36.0%) (p < 0.0001). The percentage of Type 2b fibres was directly related to BMI (r = 0.44, p = 0.02), waist circumference (r = 0.49, p = 0.009) and WHR (r = 0.44, p = 0.02) in adults. A significant, direct relationship was also found between the proportion of glycolytic Type 2b fibres and age in the adults (r = 0.45, p = 0.01).

CONCLUSION

Skeletal muscle fibre type composition is different in infants and adults and there is an age-dependent increase in Type 2b fibres over the lifespan. An increased proportion of glycolytic Type 2b fibres is associated with obesity in adults. Results support a gene-environment interaction on fibre type composition in human skeletal muscle.

Expression of the beta 3-adrenoceptor gene polymorphism (Trp64Arg) in obese diabetic and non-diabetic subjects

1. A missense mutation (Trp64Arg) in the beta 3-adrenoceptor (beta 3-AR) gene has been associated with weight gain, insulin resistance and earlier-onset non-insulin-dependent diabetes mellitus (NIDDM), but the strength of these associations varies considerably between populations and the functional significance of Trp64Arg remains unclear. 2. The Trp64Arg mutation was investigated in obese NIDDM (n = 50) and obese non-diabetic (n = 53) subjects by polymerase chain reaction (PCR) amplification of genomic DNA and digestion of the 210 bp product by BstOI. The Arg allele was found in 22.3% of all subjects, but there were no homozygotes for the mutation. Non-diabetic subjects heterozygous for the mutation were more obese and Trp/Arg diabetics had a slightly younger age of onset of NIDDM (47 vs 51 years, respectively), but there were no significant differences in mutation frequency between the two groups. Metabolic parameters (e.g. fasting lipids and glycaemic control) were similar among diabetic subjects with and without the Trp64Arg mutation. 3. In conclusion, the frequency of the Trp64Arg mutation of the beta 3-AR was higher in this obese population compared with some previous studies, but there was no evidence that Trp64Arg confers an increased susceptibility to NIDDM among obese insulin-resistant subjects or that diabetics with the mutation fare worse in terms of lipid or glucose metabolism.

The effect of an individual versus group program on weight loss

The therapy of obesity is difficult and success rates are low. Because of these observations many different therapeutic modalities have been advocated. In this study the short term weight loss results using individual and group approaches are described. For both approaches changes in lifestyle and behaviours were emphasised. The major finding of the study was that while patient retention rates were better in the group approach, weight loss was greater in those patients who were seen individually. The reasons for these findings are discussed and some suggestions are made as to how the group approach, which has the significant advantage of making more efficient use of health professionals' time, might be made more therapeutically effective.

Pharmacokinetics of dexamethasone and its relationship to dexamethasone suppression test outcome in depressed patients and healthy control subjects

The pharmacokinetics of dexamethasone (DEX) were studied in 9 drug-free melancholically depressed patients and 10 healthy control subjects matched by sex and age. Each subject received 1 mg of DEX administered orally and by the (i.v.) route at 11:00 PM and serial blood samples were collected over the next 17 hours until 4:00 PM. There were no significant differences between the diagnostic groups and DEX bioavailability, peak plasma level, time to maximum concentration, or in elimination half-life after oral administration. Bioavailability estimates indicated that DEX absorption was incomplete and variable mean = 61%, SD = 14) in controls as well as depressed patients. In both groups there was a wide interindividual variability in plasma DEX levels following both oral and i.v. routes of administration. This variability could not be reliably predicted by differences in age, sex, or weight between subjects. The factors that accounted for most the variability in 4:00 PM plasma DEX levels after oral administration were clearance, bioavailability, and time to reach maximum concentration. Plasma DEX levels were lower in 3 depressed nonsuppressors compared to 3 matched controls who suppressed. No single pharmacokinetic factor was shown to be responsible for the lower DEX levels in the depressed nonsuppressors. These results indicate that plasma DEX levels need to be measured in each individual during the DST procedure so that this information may be taken into consideration when interpreting DST results.

The effects of the inhibition of fatty acid oxidation on pyruvate dehydrogenase complex activity in tissues of lean and obese mice

OBJECTIVE

To investigate the effects of an acute dose of the fatty acid oxidation inhibitor, Etomoxir, on the activity of the pyruvate dehydrogenase complex (PDHC) in different tissues in lean and obese mice.

DESIGN

An acute dose of Etomoxir was given to mice in which obesity had been induced by an injection of gold thioglucose and to age-matched controls. The effects of time, dose and nutritional state were studied.

MEASUREMENTS

PDHC activity in heart, quadricaps muscle, liver and white adipose tissue, glycogen content of liver and quadricaps muscle, serum glucose and insulin were measured in fed and fasted animals and in fasted animals after the ingestion of a glucose load.

RESULTS

Etomoxir caused an increase in the activity of the active form of the PDHC (PDHCa) in the heart, liver and WAT of fed lean mice and in the heart and liver of fed obese mice. In fasted mice, increased PDHCa was seen in the heart of lean mice and in the liver of obese mice. Etomoxir increased the PDHC response to an oral glucose challenge in the liver and WAT of lean mice and in the liver of obese mice. Etomoxir had no effect on PDHCa in quadricaps muscle. Serum glucose levels were decreased in fasted mice with no change in the fed mice. Etomoxir decreased liver glycogen content in both fed and fasted animals and inhibited the accumulation of muscle glycogen following the glucose load.

CONCLUSIONS

Acute inhibition of fatty acid oxidation results in tissue specific increases in PDHCa. Improvements in glucose oxidation in tissues other than skeletal muscle may contribute to the improved glucose tolerance seen following acute Etomoxir administration.

Hepatic gluconeogenesis and the activity of PDH in individual tissues of GTG-obese mice following adrenalectomy

Adrenalectomy (ADX) lowers circulating glucose levels in animal models of non-insulin dependent diabetes (NIDDM) and obesity. To investigate the role of hepatic glucose production (HGP) and tissue glucose oxidation in the improvement in glucose tolerance, hepatocyte gluconeogenesis and the activity of pyruvate dehydrogenase (PDH) were examined in different tissues of gold thioglucose (GTG) obese mice 2 weeks after ADX or sham ADX. GTG-obese mice which had undergone ADX weighed significantly less than their adrenal intact counterparts (GTG ADX: 37.5 +/- 0.7 g; GTG: 44.1 +/- 0.4; p < 0.05), and demonstrated lower serum glucose (GTG ADX: 22.5 +/- 1.6 mmol/L; GTG: 29.4 +/- 1.9 mmol/L; p < 0.05) and serum insulin levels (GTG ADX: 76 +/- 10 microU/mL; GTG: 470 +/- 63 microU/mL; p < 0.05). Lactate conversion to glucose by hepatocytes isolated from ADX GTG mice was significantly reduced compared with that of hepatocytes from GTG mice (GTG ADX: 125 +/- 10 nmol glucose/10(6) cells; GTG: 403 +/- 65 nmol glucose/10(6) cells; p < 0.05). ADX also significantly reduced both the glycogen (GTG ADX: 165 +/- 27 mumol/liver; GTG: 614 +/- 60 mumol/liver; p < 0.05) and fatty acid content (GTG ADX: 101 +/- 9 mg fatty acid/g liver; GTG: 404 +/- 40 mg fatty acid/g liver; p < 0.05) of the liver of GTG-obese mice. ADX of GTG-obese mice reduced PDH activity by varying degrees in all tissues, except quadriceps muscle. These observations are consistent with an ADX induced decrease in hepatic lipid stores removing fatty acid-induced increases in gluconeogenesis and increased peripheral availability of fatty acids inhibiting PDH activity via the glucose/fatty acid cycle. It is also evident that the improvement in glucose tolerance which accompanies ADX of GTG-obese mice is not due to increased PDH activity resulting in enhanced peripheral glucose oxidation. Instead, it is more likely that reduced blood glucose levels after ADX of GTG-obese mice are the result of decreased gluconeogenesis in the liver.

A shared care approach in obesity management: the general practitioner and a hospital based service

OBJECTIVE

To describe the process of establishing a Shared Care obesity management programme between general practitioners and a hospital based specialist obesity service and to compare outcomes of the Shared Care programme (SC) to an established hospital based programme (MOS).

DESIGN

A comparative study of two obesity management programmes. Patients were matched on gender, age and BMI (kg/m2).

SUBJECTS

29 female and eight male (age: 47.0 +/- 2 years, BMI 35.9 +/- 0.8 kg/m2) patients enrolled in the Shared Care programme (SC) were matched to 81 female and 20 male (age: 45.8 +/- 1.1 years, BMI 35.7 +/- 0.4 kg/m2) patients enrolled in a hospital based programme (MOS).

MAIN OUTCOME MEASURES

Relative and absolute weight loss and retention rate were compared between the programmes at 10 and 26 weeks. Food habits were assessed at enrolment and week 10 of the programme in the SC group by a Food Habits Questionnaire and cognitive restraint, disinhibition and hunger were assessed by the Eating Inventory Questionnaire.

RESULTS

Shared Care patients (n = 28) lost significantly more weight than the MOS patients (n = 60) (SC 4.8 +/- 0.6 kg and MOS 2.6 +/- 0.4 kg; p = 0.0016) over the 10 weeks of the programme. At 26 weeks both groups demonstrated a 5 kg weight loss. There was a significant improvement in food habits, and cognitive restraint, disinhibition and hunger over the 10 weeks of the programme in the SC group. Patient satisfaction was reflected in a better retention rate at 26 weeks by the Shared Care group.

CONCLUSION

The study demonstrated that the obese patient managed in a shared care setting achieved better weight loss in the short term and attrition was lower in the longer term than a similar patient attending a specialist service based in a hospital.

Changes in glucose and lipid metabolism following weight loss produced by a very low calorie diet in obese subjects

OBJECTIVE

To study the effects of a very low calorie diet (VLCD) on glucose and lipid metabolism in obese subjects, in particular, the effects on insulin sensitivity and the activities of the key enzymes of glucose disposal, glycogen synthase (GS) and the pyruvate dehydrogenase complex (PDHC).

DESIGN

Clinical dietary intervention study (1.67 MJ (400 kcal)/day) until weight loss of > 10%.

SUBJECTS

11 (seven male, four female) non-diabetic, obese subjects (age: 27-62 y; BMI: 40.5 +/- 1.4 kg/m2).

MEASUREMENTS

Whole body glucose disposal (by euglycemic hyperinsulinemic clamp), respiratory quotient (RQ), resting energy expenditure (REE), glucose and lipid oxidation (by indirect calorimetry), insulin-stimulated PDHC and GS activity (in muscle biopsies) both before and immediately after VLCD (i.e. while still in a hypocaloric state), serum hormone and metabolite levels throughout the dietary period.

RESULTS

Weight loss was accompanied by reduced insulin and elevated NEFA levels, improved insulin sensitivity due to increased nonoxidative glycolysis with no increase in PDHC or GS activities. The rate of weight loss was inversely related to the initial RQ. PDHCa was strongly age-related.

CONCLUSION

A low RQ may be used as a predictor of the efficacy of VLCD treatment and that while VLCD improves nonoxidative glycolytic flux, changes in oxidative glucose disposal and muscle glucose storage are prevented by high NEFA availability during this catabolic phase of dietary intervention.

Insulin response to a spontaneously ingested standard meal during the development of obesity in GTG-injected mice

OBJECTIVES

(1) To determine glucose and insulin levels in response to ingestion of a standard meal during the development of gold-thioglucose (GTG)-induced obesity. (2) To examine whether the pancreatic beta-cells of GTG-injected mice possess sufficient insulin secretory capacity to compensate for the increasing tissue insulin resistance that occurs with the development of this obesity.

DESIGN

The insulin secretory response to a standard meal of chow was examined in chronically catheterised conscious mice 2, 5 and 10 weeks after induction of obesity by a single injection of GTG.

RESULTS

At 2 weeks after administration of GTG both the basal insulinaemia and the incremental area under the curve (iAUC) of insulin release after a chow meal were increased compared with age-matched lean control mice (2 week control: 1004 +/- 316 min/microU/ml; 2 week GTG: 1968 +/- 300 min/microU/ml; P < 0.05). By 5 weeks, the GTG-injected mice were approximately 42% heavier than their lean controls and showed a marked glucose intolerance. This was accompanied by hyperinsulinaemia in both the basal state and also in response to ingestion of the chow meal as indicated by the increase in the iAUC of insulin (5 week control: 1113 +/- 331 min/microU/ml; 5 week GTG: 2682 +/- 295 min/microU/ml; P < 0.05). At 10 weeks after GTG administration body weight was further increased, as was the degree of glucose intolerance. Plasma insulin levels, in both the basal state and in response to the ingestion of chow, were also further elevated by 10 weeks following GTG injection (10 week control: 1234 +/- 311 min/microU/ml; 10 week GTG: 6640 +/- 1198 min/microU/ml; P < 0.05).

CONCLUSIONS

It is apparent that the secretion of insulin in response to a standard chow meal increases progressively with the development of obesity. This finding, in conjunction with an earlier study showing that the insulin secretory response to intravenously administered glucose becomes impaired in the latter stages of the development of obesity in GTG-injected mice [Blair SC, Caterson ID, Cooney GJ. Diabetes 1993; 42: 1153-1158], suggests that the ability of beta-cells of GTG-obese animals to produce and secrete insulin is not impaired but that the beta-cells may become insensitive to glucose within the circulation.

Glucose tolerance and insulin secretion after adrenalectomy in mice made obese with gold thioglucose

The effect of adrenalectomy (ADX) on glucose tolerance and insulin secretion was examined in conscious mice made obese by a single injection of gold thioglucose (GTG). To facilitate such a study a chronic jugular catheter was implanted into the mice at the time of performing the ADX or sham-ADX. One week after ADX, the body weight (GTG-obese+sham-ADX, 35.6 +/- 0.6 g; GTG-obese+ADX, 33.1 +/- 0.6 g; P < 0.05) and glycogen content of the liver (GTG-obese+sham-ADX, 2.4 +/- 0.2 mumol/liver; GTG-obese+ADX, 1.6 +/- 0.1 mumol/liver; P < 0.05) of GTG-injected mice were reduced. Plasma glucose concentrations, in both the overnight fasted state and in response to an intravenous glucose load were also reduced following ADX of GTG-obese mice, but not to the level of the sham-ADX control mice. However, ADX completely normalized plasma insulin concentrations in both the basal state and also in response to a glucose load, as indicated by the finding that the integrated insulin secretory response of the ADX GTG-obese mice was not different from that of sham-ADX control mice (control+sham-ADX, 192 +/- 5 min.microU/ml; GTG-obese+ADX, 196 +/- 10 min.microU/ml). The effects of ADX on carbohydrate metabolism were not restricted to GTG-injected mice, as ADX of control mice decreased fasting plasma glucose levels and reduced liver glycogen and plasma insulin concentrations. The normalization of insulin release in ADX GTG-obese mice occurred while these mice were still obese and glucose intolerant. This suggests that the decreased insulin release was not due solely to an ADX-induced improvement in insulin sensitivity and/or weight loss. Removal of central glucocorticoid effects on the parasympathetic stimulation of insulin release may play a role in the reduced insulin release observed after ADX of obese and control mice, although peripheral effects of glucocorticoid deficiency on glycogen synthesis in the liver may also influence whole animal glucose homeostasis.

Skeletal muscle membrane lipids and insulin resistance

Skeletal muscle plays a major role in insulin-stimulated glucose disposal. This paper reviews the range of evidence in humans and experimental animals demonstrating close associations between insulin action and two major aspects of muscle morphology: fatty acid composition of the major structural lipid (phospholipid) in muscle cell membranes and relative proportions of major muscle fiber types. Work in vitro and in vivo in both rats and humans has shown that incorporation of more unsaturated fatty acids into muscle membrane phospholipid is associated with improved insulin action. As the corollary, a higher proportion of saturated fats is linked to impairment of insulin action (insulin resistance). Studies in vitro suggest a causal relationship. Among polyunsaturated fatty acids (PUFA) there is some, but not conclusive, evidence that omega-3 (n-3) PUFA may play a particular role in improving insulin action; certainly a high n-6/n-3 ratio appears deleterious. In relation to fiber type, the more highly oxidative, insulin-sensitive type 1 and type 2a fibers have a higher percentage of unsaturated fatty acids, particularly n-3, in their membrane phospholipid, compared to the insulin-resistant, glycolytic, type 2b fibers. These variables, however, can be separated and may act in synergy to modulate insulin action. It remains to establish whether lifestyle (e.g., dietary fatty acid profile and physical activity), genetic predisposition, or a combination are the prime determinants of muscle morphology (particularly membrane lipid profile) and hence insulin action.

Glucocorticoid deprivation alters in vivo glucose uptake by muscle and adipose tissues of GTG-obese mice

The effect of 1 wk of glucocorticoid deprivation by surgical adrenalectomy (ADX) on tissue 2-deoxy(-)[U-14C]glucose (2-DG) uptake and hepatic glucose production (HGP) was assessed in conscious, catheterized mice 5 wk after the induction of obesity with gold thioglucose (GTG). Despite the prevailing hyperglycemia and hyperinsulinemia, glucose uptake by heart, quadriceps muscle, and interscapular brown adipose tissue (BAT) of GTG-obese mice was unchanged compared with controls, suggesting that the hyperglycemia of GTG-obese mice is able to compensate for the insulin resistance of these tissues. In contrast, epididymal white adipose tissue (WAT) of GTG-obese mice showed increased glucose uptake with hyperglycemia and hyperinsulinemia. ADX decreased the hyperglycemia and lowered the elevated glycogen content of the liver of GTG-obese mice. ADX reduced glucose uptake by heart and WAT of control and GTG-obese mice, consistent with the concomitant decrease in insulinemia. Glucose uptake by muscle of control and GTG-obese mice was not significantly decreased after ADX despite the decrease in insulin, and ADX increased glucose uptake by BAT of GTG-obese mice, suggesting increased sympathetically mediated thermogenesis in this tissue. HGP was increased in GTG-obese mice compared with controls, and ADX significantly reduced HGP in both GTG-obese and control mice. These results suggest that the improved glucose tolerance of ADX GTG-obese mice and ADX control mice is due to a decrease in HGP rather than an increase in peripheral glucose uptake.

High-fat feeding alters the response of rat PDH complex to acute changes in glucose and insulin

The activity of the pyruvate dehydrogenase complex (PDHC) was studied in tissues of controls and insulin-resistant fat-fed rats (FFR) both in the fed state and in overnight fasted animals after the induction of short-term changes in plasma insulin by an intravenous glucose load. Significant responses by the PDHC to the glucose challenge were seen in heart and white adipose tissue (WAT) in controls with smaller changes in brown adipose tissue (BAT) and quadriceps muscle (QM) and no change in liver. Reduced PDHC responses and lower fed values were seen in heart and BAT of FFR. The response in WAT of FFR was prolonged with no change in the PDHC response in QM. Plasma nonesterified fatty acids (NEFA) were decreased in response to the glucose load with no differences between controls and FFR. Tissue triglyceride levels were higher in liver and QM but not heart of FFR. These results show differential tissue PDHC responses to short-term changes in plasma insulin. The decreased PDHC activity in some tissues of the fat-fed animals despite the lack of change in plasma NEFA, together with the triglyceride accumulation seen in some tissues but not others, suggests that local intracellular fatty acid metabolism is important in the regulation of intracellular glucose oxidation.