Current research studies

The following are a series of summaries of some of the research studies currently being undertaken by CORE.

Randomised Control Trials (RCTs)

Medical versus Surgical Therapy for Obesity

This study addresses a critical issue in assessing the future directions of treatments for obesity. Although there are many observational studies indicating a greater effectiveness of bariatric surgery, this has not yet been confirmed by a RCT. This study is complete. It has been presented at international scientific meetings and has been submitted for publication.

Medical versus Surgical Therapy for the Obese Type 2 Diabetic

With around 1 million Australians suffering type 2 diabetes, and most of them overweight, there is a need to test whether substantial weight loss can reverse this serious disease. This trial was commenced 30 months ago. All patients have been entered into the study and several completed the two year follow up. The study will be complete by Nov 2006.

Medical versus Surgical Therapy for the Obese Adolescent

7% of adolescents in Australia are obese. They may suffer serious health problems such as diabetes, hypertension, sleep apnoea and asthma. They may be compromised in their psychosocial and educational development, which seriously compromises their futures. This trial commenced in early 2005 to identify the best option for this group.

Medical versus Surgical Therapy for Obstructive Sleep Apnoea

Obstructive sleep apnoea is one of the diseases which is linked to the metabolic syndrome. Observational studies suggest that substantial weight loss will cure this problem. This RCT is structured to test that option. Recruitment for the study should commence in mid 2005.

Medical versus Surgical Therapy for Polycystic Ovary Syndrome (PCOS)

PCOS is present in more than 25% of morbidly obese women. As a major cause for infertility, and a probable part of the metabolic syndrome, PCOS has only been recently recognised to be so common a problem. The protocol for this RCT is currently being prepared, with the plan to commence recruitment in the latter part of 2005.

Other RCTs in the early stage of protocol preparation include comparisons of medical versus surgical therapy for depression, non-alcoholic steatohepatitis and asthma.

Observational Studies of Health Outcomes after Lap Band Placement

Long term Survival after Lap Band Placement

A key aim of treating obesity is to improve survival. In this study, the late mortality of 1505 patients following Lap Band placement, is compared with a cohort of 2105 obese people, drawn from the community in Melbourne, who have not had significant weight loss. This study should be complete by late 2005.

Pregnancy after Lap Band Placement

100 pregnancies have now occurred in 79 women after Lap Band placement. The data relating to these women and infants has been analysed with regard to changes in fertility, antenatal and perinatal events, and neonatal health. The outcomes are compared to pregnancies by these women before weight loss, pregnancies by other severely obese women, and community norms for Victoria. A report of the results has been submitted for publication.

Asthma

Following an earlier study of the effect of Lap Band placement on asthma, this study focuses on the incidence of acute exacerbations of asthma, needing hospital attendance or admission. A consecutive series of 40 moderate or severe asthmatics have been included, and each has had clinical review, completion of a questionnaire, and respiratory function tests.

Knee Pain

The weight bearing joints carry an added load in the severely obese, and degenerative disease is common. This study involves a clinical and radiological evaluation of the knees of symptomatic patients before Lap Band placement, and at 6 months, one year and two years after the placement. More than 80 of a planned 100 patients have been admitted to this study so far.

Respiratory Function and Weight Loss

The data in this area is being studied in several ways. First, almost all patients have had respiratory function tests ( RFTs) prior to Lap Band placement, and many hundreds have had those tests repeated at annual follow-up appointments. The changes which have occurred are being analysed. Second, some of these patients will be completing a 5yr follow-up point at which time a specific analysis will be made. Third, patients in the BMI 30-35 RCT had detailed assessment of respiratory function, which is now being analysed in relation to each patient's body composition at the start, and at the end, of the trial.

Studies of Mechanisms of Obesity and its Co-morbidities and Therapies

Satiety

The key mechanism of the Lap Band in generating weight loss is the inducement of satiety, the sense of lack of hunger. The pathways through which this is achieved, the time characteristics of the change in satiety with adjustment of the band and the central nervous system sites of action are being investigated by clinical, hormonal studies and by brain MRI during band adjustment.

Metabolic syndrome, visceral obesity and insulin resistance

We hypothesize that increased release of inflammatory mediators, from visceral fat macrophages, are a significant part of the pathogenesis of the metabolic syndrome and insulin resistance. Studies of samples of visceral fat, subcutaneous fat and blood are being undertaken to explore this hypothesis using flow cytometry, histology, immunohistochemistry and RNA microarray analysis.

Androgens, anti-androgens, adipokines and the metabolic syndrome in women

The relationships between insulin signaling, androgens, inflammation and non-alcoholic fatty liver disease ( NAFLD) are being studied in samples of liver, blood, visceral fat and subcutaneous fat from obese premenopausal women.

Non-alcoholic steatohepatitis (NASH)

There has been a sequence of studies characterising the effects of obesity on NAFLD and NASH, and identifying the changes in these effects which occur with weight loss. These studies are continuing with increasing focus on the aetiology of the inflammatory and fibrotic changes, and their relationship to visceral adipose tissue and its release of inflammatory mediators.

Studies of Lifestyle, Diet and Exercise

Eating behaviour and weight loss

Eating behaviour and exercise patterns are being reviewed in consecutive series of patients having the Lap Band procedure. Evaluation of these results may provide insight into predictors of weight loss after the operation. There are two accepted eating disorders in the obese binge eating disorder and night eating syndrome. The prevalence of these disorders and their relationship to outcomes after Lap Band placement are being measured.

Very Low Calorie Diets (VCLDs)

VCLDs provide a powerful non-surgical method for achieving significant short term weight loss. We have been studying VCLDs as a part of the BMI 30-35 study. Hepatomegaly and excess intraabdominal fat are common features of the preoperative massively obese. We have been characterizing the effect of VCLD on liver size and visceral fat volume during the preoperative period. The effect of VCLD on NASH is being measured by liver biopsy before and after weight loss.

Body Composition

Measurement of the changes in body fat and protein, by comprehensive body composition study, was a key part of the BMI 30-35 study. This has enabled comparison of the effects of surgical and non-surgical weight loss.

Intensive Care

Not all patients do well after Lap Band placement. Some fail to lose enough weight. The intensive care study focuses on these patients, maximizing attention to their follow up needs, seeking to identify the reversible factors, and measuring the likelihood of turning failure into success.

Cost Effectiveness Evaluations

The identification and characterization of safe and effective treatments is no longer sufficient. We must also evaluate the cost of the different options. Each of the RCTs has involved the collection of cost data. The cost-effectiveness of the two options for the general obese population ( BMI 30-35 study), for diabetics and for adolescents is being measured.

Volunteer - Research Participants Needed

The Centre for Obesity Research and Education (CORE) is always looking for people who are willing to donate their time and participate in studies in the area of obesity. Our team conducts research projects to improve knowledge leading to better management & treatment options.

More information about volunteering.