Obesity: Dixon J

Mechanick JI, Kushner RF, Sugerman HJ, Gonzalez-Campoy JM, Collazo-Clavell ML, Spitz AF, Apovian CM, Livingston EH, Brolin R, Sarwer DB, Anderson WA, Dixon J, Guven S, Anonymous00032, Anonymous00033, Anonymous00034. · No affiliation provided · Obesity (Silver Spring). · Pubmed #19319140 No free full text.

Abstract: American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health-care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Mechanick JI, Kushner RF, Sugerman HJ, Gonzalez-Campoy JM, Collazo-Clavell ML, Guven S, Spitz AF, Apovian CM, Livingston EH, Brolin R, Sarwer DB, Anderson WA, Dixon J. · No affiliation provided · Surg Obes Relat Dis. · Pubmed #18848315 No free full text.

Abstract: American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Mechanick JI, Kushner RF, Sugerman HJ, Gonzalez-Campoy JM, Collazo-Clavell ML, Guven S, Spitz AF, Apovian CM, Livingston EH, Brolin R, Sarwer DB, Anderson WA, Dixon J. · No affiliation provided · Endocr Pract. · Pubmed #18723418 No free full text.

This publication has no abstract.

Egger G, Dixon J. · Health and Applied Sciences, Southern Cross University, Australia. · Obes Rev. · Pubmed #19055538 No free full text.

Abstract: There is a link between obesity and chronic disease. However, the causal relationship is complicated. Some forms of obesity are associated with low-level systemic inflammation, which is linked to disease. But lifestyle behaviours that may not necessarily cause obesity (poor diet, inadequate sleep, smoking, etc.) can independently cause inflammation and consequent disease. It is proposed here that it is the environment driving modern lifestyles, which is the true cause of much chronic disease, rather than obesity per se, and that obesity may be a marker of environmental derangement, rather than the primary cause of the problem. Attempts to clinically manage obesity alone on a large scale are therefore unlikely to be successful at the population level without significant lifestyle or environmental change. Environmental factors influencing obesity and health have now also been implicated in ecological perturbations such as climate change, through the shift to positive energy balance in humans caused by the exponential use of fossil fuels in such areas as transport, and consequent rises in carbon emissions into the atmosphere. It is proposed therefore that a more policy-based approach to dealing with obesity, which attacks the common causes of both biological and ecological 'dis-ease', could have positive effects on both chronic disease and environmental problems. A plea is thus made for a greater health input into discussions on environmental regulation for chronic disease control, as well as climate change.

Schlaich MP, Grassi G, Lambert GW, Straznicky N, Esler MD, Dixon J, Lambert EA, Redon J, Narkiewicz K, Jordan J, Anonymous00069, Anonymous00070. · Neurovascular Hypertension and Kidney Disease Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia. · J Hypertens. · Pubmed #19155773 No free full text.

This publication has no abstract.

Banwell C, Lim L, Seubsman SA, Bain C, Dixon J, Sleigh A. · National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia. · J Epidemiol Community Health. · Pubmed #19151014 No free full text.

Abstract: BACKGROUND: Thailand is undergoing a health-risk transition with overweight and obesity emerging as an important population health problem. This paper reports on a study of the transition, focusing on "lifestyle" factors such as diet (fried foods, soft drinks, Western-style fast foods) and physical activity (mild, moderate, strenuous exercise, housework/gardening and screen time). METHODS: A baseline survey was administered to 87 134 adult students from all regions of Thailand attending an open university. RESULTS: 54% of the cohort was female. Participants' median age was 29 years. By self-reported Asian standards, 16% of the sample was obese (body mass index (BMI)>or=25) and 15% overweight at risk (BMI>or=23-24.9). Men were twice as likely as women to be overweight (21% vs 9%) or obese (23% vs 10%). Obesity was associated with urban residence and doing little housework or gardening and with spending more than 4 hours a day watching television or using computers. The latter occurred among 30% of the cohort, with a population attributable fraction (PAF) suggesting that it accounts for 11% of the current problem. Daily consumption of fried food was associated with obesity, and eating fried foods every second day or daily had a PAF of nearly 20%. CONCLUSIONS: These health-related behaviours underpinning the Thai health transition are associated with increasing obesity. They are modifiable through policies addressing structural issues and with targeted health promotion activities to prevent future obesity gains. Insights into future trends in the Thai health transition can be gained as this student cohort ages.

Peeters A, O'Brien PE, Laurie C, Anderson M, Wolfe R, Flum D, MacInnis RJ, English DR, Dixon J. · The Centre for Obesity Research and Education, Monash University, Australia. · Ann Surg. · Pubmed #18043106 No free full text.

Abstract: OBJECTIVE: To compare all-cause mortality in a surgical weight loss cohort with a similarly aged, obese population-based cohort. SUMMARY BACKGROUND DATA: Significant weight loss following bariatric surgery improves the comorbidities associated with obesity. Improved survival as a result of surgical weight loss has yet to be clearly demonstrated using clinical data. METHODS: The surgical weight loss cohort was a series of consecutive patients treated with a laparoscopic adjustable gastric band in Melbourne between June 1994 and April 2005. The Melbourne Collaborative Cohort Study (MCCS) provided a community control cohort, recruited between 1992 and 1994 and followed to June 2005 to determine vital status. Height and weight were recorded at baseline in both studies. Subjects between 37 and 70 years and with a body mass index (BMI) of > or =35 were included. Vital status was determined by follow-up and searching of death registries. Survival time was compared using Kaplan-Meier estimates, and hazard of death was determined using Cox regression, adjusting for sex, age at baseline, and BMI at baseline. RESULTS: Of 966 weight loss patients (mean age 47 years, mean BMI 45 kg/m), the median follow-up time was 4 years. Mean weight loss after 2 years was 22.8% +/- 9% (58% of excess weight). The MCCS cohort included 2119 severely obese members (mean age, 55 years; mean BMI, 38 kg/m; median follow-up time, 12 years). There were 4 deaths in the weight loss cohort and 225 deaths in the MCCS cohort. Weight loss patients had 72% lower hazard of death than the community control cohort (hazard ratio, 0.28; 95% confidence interval, 0.10-0.85). CONCLUSIONS: Substantial surgical weight loss in a morbidly obese population was associated with a significant survival advantage.

Ratziu V, Bugianesi E, Dixon J, Fassio E, Ekstedt M, Charlotte F, Kechagias S, Poynard T, Olsson R. · Université Pierre et Marie Curie and Assistance Publique, Hôpitaux de Pairs, Service d'Hépatogastroentérologie, Groupe Hospitalier Pitié Salpêtrière, Paris, France. · Aliment Pharmacol Ther. · Pubmed #17767466 No free full text.

Abstract: BACKGROUND: In non-alcoholic fatty liver disease, histological lesions display a significant sampling variability that is ignored when interpreting histological progression during natural history or therapeutic interventions. AIM: To provide a method taking into account sampling variability when interpreting crude histological data, and to investigate how this alters the conclusions of available studies. METHODS: Natural history studies detailing histological progression and therapeutic trials were compared with the results of a previously published sampling variability study. RESULTS: Natural history studies showed an improvement in steatosis, which was significantly higher than expected from sampling variability (47% vs. 8%, P < 0.0001). In contrast, no study showed a change in activity grade or ballooning higher than that of sampling variability. There was only a marginal effect on fibrosis with no convincing demonstration of a worsening of fibrosis, a conclusion contrary to what individual studies have claimed. Some insulin sensitizing drugs and anti-obesity surgery significantly improved steatosis, while most did not significantly impact on fibrosis or activity. CONCLUSIONS: Sampling variability of liver biopsy is an overlooked confounding factor that should be considered systematically when interpreting histological progression in patients with non-alcoholic fatty liver disease.

Banwell C, Hinde S, Dixon J, Sibthorpe B. · National Centre for Epidemiology and Population Health, Australian National University, Canberra, ACT, Australia. · Eur J Public Health. · Pubmed #16141305 links to  free full text

Abstract: BACKGROUND: In Australia, as elsewhere in the developed world, researchers and policy makers have expressed concern about rising rates of obesity. Explanations for the increasing weight of the Australian population have focused on both declining levels of physical activity and changes in food consumption patterns. METHODS: The primary aim of our study was to determine the views of obesity, dietary and physical activity experts, about the most important social trends that have contributed to Australia's obesogenic environment over the last 50 years. We used a modified Delphi technique to successfully contact 50 such experts to obtain their views on this topic. The process involved a semi-structured interview with each expert to identify the trends and then a round of ranking of the trends by these experts. A second aim was to comment on the utility of expert opinion in public policy. RESULTS: The experts identified the most important social trends as 'escalating car reliance', 'increasing "busy-ness" and lack of time' and 'rising use of convenience and pre-prepared food'. Because we asked experts to explain their responses, a diversity of opinion emerged on both the aetiology of these trends and how the environment is embodied to produce rising levels of obesity. CONCLUSION: We reflect on the implications of this dissensus for the utility of expert opinion in public policy and argue that one way through the smorgasboard of competing expert explanations for health differentials, including obesity levels, is practice-based evidence gathered through community level action research.

Challis BG, Coll AP, Yeo GS, Pinnock SB, Dickson SL, Thresher RR, Dixon J, Zahn D, Rochford JJ, White A, Oliver RL, Millington G, Aparicio SA, Colledge WH, Russ AP, Carlton MB, O'Rahilly S. · Department of Clinical Biochemistry and Medicine, Cambridge Institute for Medical Research, Addenbrookes Hospital, Cambridge CB2 2XY, United Kingdom. · Proc Natl Acad Sci U S A. · Pubmed #15070780 links to  free full text

Abstract: Inactivating mutations of the pro-opiomelanocortin (POMC) gene in both mice and humans leads to hyperphagia and obesity. To further examine the mechanisms whereby POMC-deficiency leads to disordered energy homeostasis, we have generated mice lacking all POMC-derived peptides. Consistent with a previously reported model, Pomc(-/-) mice were obese and hyperphagic. They also showed reduced resting oxygen consumption associated with lowered serum levels of thyroxine. Hypothalami from Pomc(-/-) mice showed markedly increased expression of melanin-concentrating hormone mRNA in the lateral hypothalamus, but expression of neuropeptide Y mRNA in the arcuate nucleus was not altered. Provision of a 45% fat diet increased energy intake and body weight in both Pomc(-/-) and Pomc(+/-) mice. The effects of leptin on food intake and body weight were blunted in obese Pomc(-/-) mice whereas nonobese Pomc(-/-) mice were sensitive to leptin. Surprisingly, we found that Pomc(-/-) mice maintained their acute anorectic response to peptide-YY(3-36) (PYY(3-36)). However, 7 days of PYY(3-36) administration had no effect on cumulative food intake or body weight in wild-type or Pomc(-/-) mice. Thus, POMC peptides seem to be necessary for the normal response of energy balance to high-fat feeding, but not for the acute anorectic effect of PYY(3-36) or full effects of leptin on feeding. The finding that the loss of only one copy of the Pomc gene is sufficient to render mice susceptible to the effects of high fat feeding emphasizes the potential importance of this locus as a site for gene-environment interactions predisposing to obesity.

Schachter LM, Dixon J, Pierce RJ, O'Brien P. · Institute for Breathing and Sleep, Austin and Repatriation Medical Centre, Heidelberg, VIC, Australia. · Chest. · Pubmed #12796170 links to  free full text

Abstract: OBJECTIVE: To assess whether severe gastroesophageal reflux (GER) is associated with abnormalities in lung function including measures of lung volume and gas diffusion. METHODS: Data from 147 patients with obesity (body mass index [BMI] range, 31.7 to 70 kg/m(2)) who presented for obesity surgery was analyzed retrospectively. A questionnaire was completed preoperatively that included a history of GER, frequency and severity of symptoms, investigations, and medications used. A history of lung disease, sleep-disordered breathing, and smoking also was obtained. A physician who was blinded to lung function graded GER severity prospectively by the results of pH monitoring and/or gastroscopy, and medication use. Spirometry, lung volumes, and gas transfer were measured preoperatively. RESULTS: Patients with severe GER had reduced levels of the diffusing capacity of the lung for carbon monoxide (DLCO) [21.1 mL/min/mm Hg; 95% confidence interval (CI), 18.9 to 23.2], as measured by CO transfer, compared with those patients without GER (26.3 mL/min/mm Hg; 95% CI, 24.4 to 28.2; p = 0.001). This remained significant after adjusting for age, gender, BMI, and smoking history. Gas transfer corrected for lung volume also was reduced in the group with severe GER (4.6 mL/min/mm Hg per L; 95% CI, 4.3 to 4.9) compared to the group without GER (5.3 mL/min/mm Hg per L; 95% CI, 5.1 to 5.5; p = 0.001). There was no significant difference in other measures of lung function. CONCLUSIONS: Severe GER is associated with an impairment of gas exchange. This may be due to microaspiration of gastric acid or fluid into the airways.

O'Brien P, Brown W, Dixon J. · Monash University Department of Surgery, Alfred Hospital, Melbourne, Australia. · Obes Surg. · Pubmed #11175966 No free full text.

Abstract: BACKGROUND: The safety and effectiveness of conversion to the Lap-Band system, of patients who had failure of adequate weight loss and/or severe symptoms from prior bariatric procedures has been measured by prospective evaluation of a consecutive group of 50 patients. METHODS: The patients were drawn as a subgroup of 713 patients who had placement of the Lap-Band system between July 1994 and May 2000. The preceding procedures were gastroplasty (35 patients), non-adjustable gastric banding (11), gastric bypass (2) and jejuno-ileal bypass (2). All operations were by open laparotomy. Initial reversal of the initial procedure was performed in 28 patients. M:F ratio was 6%/94%. Inadequate weight was the primary problem in 69%, and symptoms of obstruction were present in 31%. RESULTS: Significant perioperative complications occurred more frequently than after primary placement (17% vs 1.1%). However, late complications were less frequent (2% vs 18%). In particular, there have been no occurrences of prolapse (slippage) of the stomach through the band or erosion of the band into the stomach in this group to date. Weight loss of 47% of excess weight had occurred at 3-year follow-up. This is not significantly different from the 53% EWL in the primary Lap-Band group. All symptoms of obstruction were relieved by the revision, and a number of comorbidities are seen to be markedly improved. CONCLUSIONS: We observe that, when compared to primary Lap-Band placement, revision of failed bariatric procedures to Lap-Band is associated with more perioperative adverse events but fewer late complications. Weight loss is equivalent and is associated with marked improvement in comorbidities and quality of life.The outcomes are better than have been achieved by revision to another form of gastric stapling and should be considered in those patients who have had an unsatisfactory outcome from other bariatric procedures.

Dixon J. · Centre for Obesity Research and Education, Monash University, Alfred Hospital, Melbourne, Victoria, Australia. · Surg Obes Relat Dis. · Pubmed #17138228 No free full text.

This publication has no abstract.

Mechanick JI, Kushner RF, Sugerman HJ, Gonzalez-Campoy JM, Collazo-Clavell ML, Guven S, Spitz AF, Apovian CM, Livingston EH, Brolin R, Sarwer DB, Anderson WA, Dixon J, Anonymous00003, Anonymous00004, Anonymous00005. · No affiliation provided · Endocr Pract. · Pubmed #18463039 No free full text.

This publication has no abstract.