Obesity in North America. An overview

Influence of BMI percentile on craniofacial morphology and development in children and adolescents

BACKGROUND

The prevalence of childhood and adolescent obesity is increasing worldwide. Reports suggest that elevated body mass index (BMI) is associated with larger craniofacial dimensions and advanced dental and skeletal development. Such an association is important for timing orthodontic treatment relative to pubertal growth and dental eruption.

MATERIALS AND METHODS

To evaluate associations between BMI, craniofacial morphology, dental age, and cervical vertebrae maturation staging (CVMS), 400 participants were consecutively selected (8-15 years, n = 200 overweight and obese BMI >85%, 200 normal weight) from the University of North Carolina database. Records were analysed for cephalometric measures, Demirjian index values, and CVMS. Bivariate statistics and linear regression analysis evaluated whether CVMS, dental age, and cephalometric dimensions varied with BMI.

RESULTS

Overweight/obese children and adolescents had a proportionally larger bimaxillary prognathic skeletal pattern compared to those of normal weight. These cephalometric measurements [articulare-gnathion (Ar-Gn), condylion-anterior nasal spine (Co-ANS), sella-gonion (S-Go), nasion-menton (N-Me), anterior nasal spine-menton (ANS-Me), sella-nasion-A point (SNA), sella-nasion-B point (SNB), and sella-nasion-pogonion (SNPg)] were significantly different [statistically (P < 0.05) and clinically (>2 mm or >2 degrees)] between the two study groups, with a linear relationship between BMI percentile and craniofacial dimension. The overweight/obese BMI group had a mean dental age 1.4 years advanced relative to the normal weight group (P < 0.05), with an advancement of nearly one CVM stage between the ages of 12 and 14 (P < 0.05).

LIMITATIONS

The study is retrospective.

CONCLUSIONS

Obese/overweight children and adolescents have proportionally larger antero-posterior and vertical dimensions and are more likely to experience advanced dental and skeletal maturation. Obese/overweight subjects may enter their growth spurt at a younger age and have earlier eruption of teeth, affecting treatment timing. BMI percentile should be a consideration for orthodontic treatment in growing patients.

Continuous Engagement in a Weight-Loss Program Promotes Sustained Significant Weight Loss

BACKGROUND

Significant weight loss improves health but regain is common.

OBJECTIVE

The objective of the study was to determine if 2,346 members of Take Off Pounds Sensibly-a national, low-cost, peer-led weight-loss program-achieved and maintained significant weight loss with 7 consecutive annual renewals.

METHODS

This study was a retrospective cohort design. For each renewal, the cumulative change from baseline weight was calculated. Weight change was placed into 1 of 3 categories: significant weight loss, loss ≥ 5%; weight stable, loss of 0 to < 5%; or weight gain, any amount above baseline weight.

RESULTS

The cohort included 2,346 individuals. Fifty-one percent (n=740) of participants were in the significant weight-loss category all 7 years; 256 (18%) were in the significant weight-loss category at year 1 but moved into at least 1 other category during years 2 through 6; 359 (25%) were in the weight stable category at year 1; and 98 (7%) were in the weight gain category at year 1.

CONCLUSIONS

Over 60% of the population achieved significant weight loss by year 7. Since continuous, long-term engagement in a weight-loss program can lead to significant weight loss, even if significant weight loss is not initially achieved, participation should be encouraged.

How the association between obesity and inflammation may lead to insulin resistance and cancer

BACKGROUND AND OBJECTIVES

Obesity is associated with metabolic dysfunction and over nutrition. Increased body mass index and obesity are strongly amalgamated with changes in the physiological function of adipose tissue, leading to altered secretion of adipocytokines, inflammatory mediators release as well as chronic inflammation and insulin resistance. The purposes of this study were to review the evidence of how obesity and inflammation may lead to insulin resistance and cancer.

SUMMARY

Recent findings suggested that increased level of inflammatory mediators in obesity, plays an introductory and cabalistic role in the development of different types of inflammatory disorders including type 2 diabetes mellitus. Link between elevated body mass index and type 2 diabetes mellitus (T2DM). Several of the factors-such as increased levels of leptin, plasminogen activator inhibitor-1, decreased levels of adiponectin, insulin resistance, chronic inflammation etc. consequently result in carcinogenesis and carcinogenic progression too.

CONCLUSION

This review summarizes how cytokine production in adipose tissue of obese subject creates a chronic inflammatory environment that favors tumor cell motility and invasion to enhance the metastatic potential of tumor cells. High levels of cytokine in the circulation of affected individuals have been associated with a significantly worse outcome. This article also reconnoiters the mechanisms that link obesity to numerous disorders such as inflammation, diabetes, cancers and most specifically combine these processes in a single image. Understanding these mechanisms may assist to understand the consequences of obesity.

The gut-brain axis in obesity

Currently the only effective treatment for morbid obesity with a proven mortality benefit is surgical intervention. The underlying mechanisms of these surgical techniques are unclear, but alterations in circulating gut hormone levels have been demonstrated to be at least one contributing factor. Gut hormones seem to communicate information from the gastrointestinal tract to the regulatory appetite centres within the central nervous system (CNS) via the so-called 'Gut-Brain-Axis'. Such information may be transferred to the CNS either via vagal or non-vagal afferent nerve signalling or directly via blood circulation. Complex neural networks, distributed throughout the forebrain and brainstem, are in control of feeding and energy homoeostasis. This article aims to review how appetite is potentially regulated by these gastrointestinal hormones. Identification of the underlying mechanisms of appetite and weight control may pave the way to develop better surgical techniques and new therapies in the future.

Replication of 6 obesity genes in a meta-analysis of genome-wide association studies from diverse ancestries

Obesity is a major public health problem with a significant genetic component. Multiple DNA polymorphisms/genes have been shown to be strongly associated with obesity, typically in populations of European descent. The aim of this study was to verify the extent to which 6 confirmed obesity genes (FTO, CTNNBL1, ADRB2, LEPR, PPARG and UCP2 genes) could be replicated in 8 different samples (n = 11,161) and to explore whether the same genes contribute to obesity-susceptibility in populations of different ancestries (five Caucasian, one Chinese, one African-American and one Hispanic population). GWAS-based data sets with 1000 G imputed variants were tested for association with obesity phenotypes individually in each population, and subsequently combined in a meta-analysis. Multiple variants at the FTO locus showed significant associations with BMI, fat mass (FM) and percentage of body fat (PBF) in meta-analysis. The strongest association was detected at rs7185735 (P-value = 1.01×10(-7) for BMI, 1.80×10(-6) for FM, and 5.29×10(-4) for PBF). Variants at the CTNNBL1, LEPR and PPARG loci demonstrated nominal association with obesity phenotypes (meta-analysis P-values ranging from 1.15×10(-3) to 4.94×10(-2)). There was no evidence of association with variants at ADRB2 and UCP2 genes. When stratified by sex and ethnicity, FTO variants showed sex-specific and ethnic-specific effects on obesity traits. Thus, it is likely that FTO has an important role in the sex- and ethnic-specific risk of obesity. Our data confirmed the role of FTO, CTNNBL1, LEPR and PPARG in obesity predisposition. These findings enhanced our knowledge of genetic associations between these genes and obesity-related phenotypes, and provided further justification for pursuing functional studies of these genes in the pathophysiology of obesity. Sex and ethnic differences in genetic susceptibility across populations of diverse ancestries may contribute to a more targeted prevention and customized treatment of obesity.

Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty

Background and Aims

Gastric bypass results in greater weight loss than Vertical banded gastroplasty (VBG), but the underlying mechanisms remain unclear. In addition to effects on energy intake the two bariatric techniques may differentially influence energy expenditure (EE). Gastric bypass in rats increases postprandial EE enough to result in elevated EE over 24 hours. This study aimed to investigate alterations in postprandial EE after gastric bypass and VBG in humans.

Methods

Fourteen women from a randomized clinical trial between gastric bypass (n = 7) and VBG (n = 7) were included. Nine years postoperatively and at weight stability patients were assessed for body composition and calorie intake. EE was measured using indirect calorimetry in a respiratory chamber over 24 hours and focused on the periods surrounding meals and sleep. Blood samples were analysed for postprandial gut hormone responses.

Results

Groups did not differ regarding body composition or food intake either preoperatively or at study visit. Gastric bypass patients had higher EE postprandially (p = 0.018) and over 24 hours (p = 0.048) compared to VBG patients. Postprandial peptide YY (PYY) and glucagon like peptide 1 (GLP-1) levels were higher after gastric bypass (both p<0.001).

Conclusions

Gastric bypass patients have greater meal induced EE and total 24 hours EE compared to VBG patients when assessed 9 years postoperatively. Postprandial satiety gut hormone responses were exaggerated after gastric bypass compared to VBG. Long-term weight loss maintenance may require significant changes in several physiological mechanisms which will be important to understand if non-surgical approaches are to mimic the effects of bariatric surgery.

Physical, Behavioral, and Body Image Characteristics in a Tri-Racial Group of Adolescent Girls

OBJECTIVES

The purpose of this study was to evaluate physical characteristics, nutrient intake, physical activity level, and body image in white (CC), African-American (AA), and Hispanic-American (HA) female adolescents.

RESEARCH METHODS AND PROCEDURES

High school volunteers were solicited for this study. Self-reported information was used to determine subject characteristics, family income, physical activity, body image, and nutrient intake. Physical evaluations were used to determine body mass index, percent body fat, fat distribution, resting heart rate, and blood pressure (BP).

RESULTS

Results showed that AA girls displayed significantly higher diastolic BP than HA girls (p = 0.029). CC adolescents showed greater physical activity (p = 0.010) and lower adiposity than HA adolescents (p = 0.048), as well as lower subscapular skinfold than AA adolescents (p = 0.018). AA adolescents selected a higher ideal body size than CC girls (p = 0.038). There was also a significant difference in percentage carbohydrates (p < 0.034) and cholesterol consumed (p < 0.016) among groups, with CC girls showing the highest values for carbohydrates and lowest values for cholesterol intake among groups.

DISCUSSION

Given our findings of higher adiposity and lower physical activity levels in HA adolescents and greater diastolic BP levels and subscapular skinfold in AA adolescents, more interventions should be targeted toward improving health-related variables among minority populations.

Increased energy expenditure in gastric bypass rats is not caused by activated brown adipose tissue

OBJECTIVE

To investigate whether gastric bypass induces a higher activity of brown adipose tissue and greater levels of the brown adipose tissue-specific protein uncoupling protein-1 (UCP-1) in rats.

METHODS

Gastric bypass rats and sham-operated controls (each n = 8) underwent whole body (1)H-MR spectroscopy for analysis of body composition and (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography ((18)F-FDG PET/CT) imaging for measurement of the metabolic activity of brown adipose tissue. Brown adipose tissue was harvested and weighed, and UCP-1 mRNA content was measured by Northern Blot technique.

RESULTS

Gastric bypass rats had a significantly lower percentage of whole body adipose tissue mass compared to sham-operated rats (p = 0.001). There was no difference in brown adipose tissue activity between the two groups (standardised uptake value sham 2.81 ± 0.58 vs. bypass 2.56 ± 0.46 ; p = 0.73). Furthermore, there was no difference in the UCP-1 mRNA content of brown adipose tissue between the two groups (sham 49.5 ± 13.2 vs. bypass 43.7 ± 13.1; p = 0.77).

CONCLUSION

Gastric bypass does not increase the activity of brown adipose tissue in rats suggesting that other mechanisms are involved to explain the increased energy expenditure after bypass surgery. Our results cannot justify the radiation dose of (18)F-FDG PET/CT studies in humans to determine potential changes in brown adipose tissue after gastric bypass surgery.

Gastrointestinal hormones, energy balance and bariatric surgery

Despite increasing understanding of the changes in gastrointestinal and central neuroendocrine signaling following gastric bypass surgery (GBP) in morbidly obese patients, the mechanisms underlying weight loss and weight loss maintenance are not completely understood. Changes in energy expenditure are increasingly recognized as an important factor contributing to weight loss and metabolic effects in patients following GBP surgery. Experimental data regarding changes in energy balance following metabolic surgery in animal models suggest increased energy expenditure postoperatively as an important factor in the process of weight loss. However, the underlying neuroendocrine mechanisms are not well understood, and data regarding changes in energy expenditure in humans after GBP are inconsistent because of heterogenic patient populations and variable techniques. Nevertheless, a growing body of knowledge and understanding of the complex entero-neurohumoral interaction with its consequences in appetite, satiety and energy expenditure will help reveal the mechanisms of weight loss and weight loss maintenance following GBP surgery. Here we review how gastrointestinal hormones potentially regulate energy balance, and summarize current available experimental and clinical data on energy expenditure following obesity surgery.

Obesity: overview of an epidemic

The obesity epidemic in the United States has proven difficult to reverse. We have not been successful in helping people sustain the eating and physical activity patterns that are needed to maintain a healthy body weight. There is growing recognition that we will not be able to sustain healthy lifestyles until we are able to address the environment and culture that currently support unhealthy lifestyles. Addressing obesity requires an understanding of energy balance. From an energy balance approach it should be easier to prevent obesity than to reverse it. Further, from an energy balance point of view, it may not be possible to solve the problem by focusing on food alone. Currently, energy requirements of much of the population may be below the level of energy intake than can reasonably be maintained over time. Many initiatives are underway to revise how we build our communities, the ways we produce and market our foods, and the ways we inadvertently promote sedentary behavior. Efforts are underway to prevent obesity in schools, worksites, and communities. It is probably too early to evaluate these efforts, but there have been no large-scale successes in preventing obesity to date. There is reason to be optimistic about dealing with obesity. We have successfully addressed many previous threats to public health. It was probably inconceivable in the 1950s to think that major public health initiatives could have such a dramatic effect on reducing the prevalence of smoking in the United States. Yet, this serious problem was addressed via a combination of strategies involving public health, economics, political advocacy, behavioral change, and environmental change. Similarly, Americans have been persuaded to use seat belts and recycle, addressing two other challenges to public health. But, there is also reason to be pessimistic. Certainly, we can learn from our previous efforts for social change, but we must realize that our challenge with obesity may be greater. In the other examples cited, we had clear goals in mind. Our goals were to stop smoking, increase the use of seatbelts, and increase recycling. The difficulty of achieving these goals should not be minimized, but they were clear and simple goals. In the case of obesity, there is no clear agreement about goals. Moreover, experts do not agree on which strategies should be implemented on a widespread basis to achieve the behavioral changes in the population needed to reverse the high prevalence rates of obesity. We need a successful model that will help us understand what to do to address obesity. A good example is the recent HEALTHY study. This comprehensive intervention was implemented in several schools and aimed to reduce obesity by concentrating on behavior and environment. This intervention delivered most of the strategies we believe to be effective in schools. Although the program produced a reduction in obesity, this reduction was not greater than the reduction seen in the control schools that did not receive the intervention. This does not mean we should not be intervening in schools, but rather that it may require concerted efforts across behavioral settings to reduce obesity. Although we need successful models, there is a great deal of urgency in responding to the obesity epidemic. An excellent example is the effort to get menu labeling in restaurants, which is moving rapidly toward being national policy. The evaluation of this strategy is still ongoing, and it is not clear what impact it will have on obesity rates. We should be encouraging efforts like this, but we must evaluate them rigorously. Once we become serious about addressing obesity, it will likely take decades to reverse obesity rates to levels seen 30 years ago. Meanwhile, the prevalence of overweight and obesity remains high and quite likely will continue to increase.

Gastric bypass reduces fat intake and preference

Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation.

The epidemiology and aetiology of obesity: a global challenge

Positive energy imbalance Energy imbalance leads to obesity. A majority of the US population is overweight, a third obese and nearly 5% morbidly obese. In the developing world, this problem continues to evolve in an rapid manner, creating challenges for already burdened health systems. In many instances, the environment contributes to the problem. Factors ranging from the availability of calorie-dense foods, decreased time spent in physical activities, technologically assisted household chores to time spent watching television, all have some contribution to the problem. Much more needs to be done to control this obesity epidemic, both from a public health as well as a communal-expense perspective. Forced misuse of economic resources and wasted potential lives should drive a better coordinated effort to control what could possibly be the biggest health challenge of the 21st century.

Body weight dissatisfaction in the Icelandic adult population: a normative discontent?

BACKGROUND

Body weight dissatisfaction is a common problem in many modern societies and it appears to have grown over time. This study examined the prevalence and predictors of body weight dissatisfaction among 18- to 79-year-old Icelanders. The distribution of body weight dissatisfaction according to the WHO body mass index criteria for underweight, normal weight, overweight and obesity was also assessed.

METHODS

The study was based on 5832 participants in the cross-sectional survey 'Health and Well-Being of Icelanders', administered by the Public Health Institute in Iceland in the fall of 2007.

RESULTS

Around 43% of adult Icelanders are dissatisfied with their own body weight (50% of females; 35% of males) and 72% believe they need to lose weight (80% of females; 63% of males). Despite being in normal range according to the WHO-based BMI criteria, 64% of females in that category believe they need to lose weight. Multivariate results show that indicators of socio-economic status (SES) are not significantly associated with body weight dissatisfaction among females, while among males, those with university education are more often dissatisfied than those with secondary education (OR = 1.5, P < 0.05; for self-perceived need to lose weight, estimates are OR = 1.4, P < 0.05 for females, and OR = 2.5, P < 0.001 for males).

CONCLUSION

The prevalence of body dissatisfaction is so prominent among Icelandic female adults that it can rightfully be labelled a normative discontent in this population.

Vagal sparing surgical technique but not stoma size affects body weight loss in rodent model of gastric bypass

BACKGROUND

The aim of this study was to evaluate whether gastric bypass with or without vagal preservation resulted in a different outcome.

METHODS

Body weight, food intake and postprandial peptide YY (PYY) and glucagon-like peptide (GLP-1) levels were compared between gastric bypass (n = 55) and sham-operated rats (n = 27) in three groups. In group 1 (n = 17), the vagal nerve was not preserved, while in group 2 the vagal nerve was preserved during gastric bypass (n = 10). In group 3, gastric bypass rats (n = 28) were randomised for either one of the two techniques.

RESULTS

Rats in which the vagal nerve was preserved during gastric bypass showed a lower body weight (p < 0.001) and reduced food intake (p < 0.001) compared to rats in which the vagal nerve was not preserved during the gastric bypass operation. Levels of PYY and GLP-1 were significantly increased after gastric bypass compared to sham-operated controls (p < 0.05), but there was no difference between gastric bypass rats with and without vagal preservation. Differences in food intake and body weight were not related to the size of the gastro-jejunostomy in gastric bypass rats. There were no signs of malabsorption or inflammation after gastric bypass.

CONCLUSION

We propose that the vagal nerve should be preserved during the gastric bypass operation as this might play an important role for the mechanisms that induce weight loss and reduce food intake in rats. In contrast, the gastro-jejunal stoma size was found to be of minor relevance.

Gastric bypass increases energy expenditure in rats

BACKGROUND & AIMS

Mechanisms underlying weight loss maintenance after gastric bypass are poorly understood. Our aim was to examine the effects of gastric bypass on energy expenditure in rats.

METHODS

Thirty diet-induced obese male Wistar rats underwent either gastric bypass (n = 14), sham-operation ad libitum fed (n = 8), or sham-operation body weight-matched (n = 8). Energy expenditure was measured in an open circuit calorimetry system.

RESULTS

Twenty-four-hour energy expenditure was increased after gastric bypass (4.50 +/- 0.04 kcal/kg/h) compared with sham-operated, ad libitum fed (4.29 +/- 0.08 kcal/kg/h) and sham-operated, body weight-matched controls (3.98 +/- 0.10 kcal/kg/h, P < .001). Gastric bypass rats showed higher energy expenditure during the light phase than sham-operated control groups (sham-operated, ad libitum fed: 3.63 +/- 0.04 kcal/kg/h vs sham-operated, body weight-matched: 3.42 +/- 0.05 kcal/kg/h vs bypass: 4.12 +/- 0.03 kcal/kg/h, P < .001). Diet-induced thermogenesis was elevated after gastric bypass compared with sham-operated, body weight-matched controls 3 hours after a test meal (0.41% +/- 1.9% vs 10.5% +/- 2.0%, respectively, P < .05). The small bowel of gastric bypass rats was 72.1% heavier because of hypertrophy compared with sham-operated, ad libitum fed rats (P < .0001).

CONCLUSIONS

Gastric bypass in rats prevented the decrease in energy expenditure after weight loss. Diet-induced thermogenesis was higher after gastric bypass compared with body weight-matched controls. Raised energy expenditure may be a mechanism explaining the physiologic basis of weight loss after gastric bypass.

The obesity epidemic

Obesity has reached epidemic proportions in the United States, with 35.1% of adults being classified as obese. Obesity affects every segment of the US population and continues to increase steadily, especially in children. Obesity increases the risk for many other chronic diseases, including diabetes mellitus, cardiovascular disease, and nonalcoholic fatty liver disease, and decreases overall quality of life. The current US generation may have a shorter life expectancy than their parents if the obesity epidemic is not controlled, and there is no indication that the prevalence of obesity is decreasing. Because of the complexity of obesity, it is likely to be one of the most difficult public health issues our society has faced.

Powerful bivariate genome-wide association analyses suggest the SOX6 gene influencing both obesity and osteoporosis phenotypes in males

Background

Current genome-wide association studies (GWAS) are normally implemented in a univariate framework and analyze different phenotypes in isolation. This univariate approach ignores the potential genetic correlation between important disease traits. Hence this approach is difficult to detect pleiotropic genes, which may exist for obesity and osteoporosis, two common diseases of major public health importance that are closely correlated genetically.

Principal Findings

To identify such pleiotropic genes and the key mechanistic links between the two diseases, we here performed the first bivariate GWAS of obesity and osteoporosis. We searched for genes underlying co-variation of the obesity phenotype, body mass index (BMI), with the osteoporosis risk phenotype, hip bone mineral density (BMD), scanning ∼380,000 SNPs in 1,000 unrelated homogeneous Caucasians, including 499 males and 501 females. We identified in the male subjects two SNPs in intron 1 of the SOX6 (SRY-box 6) gene, rs297325 and rs4756846, which were bivariately associated with both BMI and hip BMD, achieving p values of 6.82×10⁻⁷ and 1.47×10⁻⁶, respectively. The two SNPs ranked at the top in significance for bivariate association with BMI and hip BMD in the male subjects among all the ∼380,000 SNPs examined genome-wide. The two SNPs were replicated in a Framingham Heart Study (FHS) cohort containing 3,355 Caucasians (1,370 males and 1,985 females) from 975 families. In the FHS male subjects, the two SNPs achieved p values of 0.03 and 0.02, respectively, for bivariate association with BMI and femoral neck BMD. Interestingly, SOX6 was previously found to be essential to both cartilage formation/chondrogenesis and obesity-related insulin resistance, suggesting the gene's dual role in both bone and fat.

Conclusions

Our findings, together with the prior biological evidence, suggest the SOX6 gene's importance in co-regulation of obesity and osteoporosis.

Sir David Cuthbertson Medal Lecture Bariatric surgery as a model to study appetite control

The obesity epidemic and its associated morbidity and mortality have led to major research efforts to identify mechanisms that regulate appetite. Gut hormones have recently been found to be an important element in appetite regulation as a result of the signals from the periphery to the brain. Candidate hormones include ghrelin, peptide YY, glucagon-like peptide-1 and gastric inhibitory polypeptide, all of which are currently being investigated as potential obesity treatments. Bariatric surgery is currently the most effective therapy for substantial and sustained weight loss. Understanding how levels of gut hormones are modulated by such procedures has greatly contributed to the comprehension of the underlying mechanisms of appetite and obesity. The present paper is a review of how appetite and levels of gastrointestinal hormones are altered after bariatric surgery. Basic principles of common bariatric procedures and potential mechanisms for appetite regulation by gut hormones are also addressed.

Mechanisms of weight loss after gastric bypass and gastric banding

The obesity epidemic is a major health problem that is associated with increased morbidity and mortality. Gastrointestinal hormones have been increasingly understood to be an important element in appetite regulation. Several gastrointestinal hormones can contribute to obesity by modulating the activity of the gut-brain axis. Bariatric surgery is currently the most effective therapy for significant and sustained weight loss in morbidly obese patients. Understanding how gut hormones are altered by bariatric procedures has contributed to our understanding of the mechanisms of appetite. In this review, we address several gastrointestinal hormones that are associated with obesity and consider how their levels are altered after bariatric surgery. The review also addresses specific effects of different gut hormones on appetite, hunger, and energy balance.

[High-carbohydrate diets: effects on lipid metabolism, body adiposity and its association with physical activity and cardiovascular disease risk]

For many years the reduction in the dietary fat has been recommended to the population, in order to prevent cardiovascular diseases, obesity, type 2 diabetes mellitus, among other chronic diseases. The consequence has been the replacement of carbohydrates by fat, resulting in the adoption of high carbohydrate diets. However, it has been still discussed if very rich carbohydrate diets should be recommended to the general population. Researches point out controversies about the association between these dietary habits and harmful effects on health and metabolic aspects, such as raise in de novo lipogenesis and triglyceride concentration, reduction in HDL concentration and effects on adiposity. This review evaluates the effects of diet modification, particularly the high-carbohydrate diet, in cardiovascular risk factors such as dyslipidemia and obesity. It also reviews its interaction with physical activity since it is still unknown with which extension it can minimize possible harmful effects of high carbohydrate diets in the long term.

Relationships between human thirst, hunger, drinking, and feeding

There is a widely held view that hunger prompts feeding to ensure energy needs are met, while thirst cues drinking to address hydration requirements. However, recent changes in the nature of the food supply and eating patterns have raised questions about the functionality of these relationships with respect to maintaining energy balance. The increasing consumption of energy-yielding beverages and foods with diluted energy density, through the use of ingredients such as high-intensity sweeteners and fat replacers, poses new challenges to presumed homeostatic energy regulatory mechanisms. This review draws on findings from a recent observational study and other published evidence to explore whether shifts of food composition and use patterns may be disrupting relationships between thirst, hunger, drinking, and eating, resulting in positive energy balance (e.g., drinking low satiety, energy-yielding beverages in response to hunger). The observational study entailed collecting hourly appetitive ratings and dietary recalls from 50 adults for seven consecutive days. These data reveal a clear bimodal daily hunger pattern, whereas thirst is stronger and more stable throughout the day. Further, approximately 75% of fluid intake occurs peri-prandially, with the majority derived from energy-yielding beverages. While there is published evidence that drinking is responsive to feeding, support for the view that drinking is the more tightly regulated behavior is stronger. Our data indicates that, due to a number of plausible factors, neither absolute values nor changes of hunger or thirst are strong predictors of energy intake. However, it is proposed that stable, high thirst facilitates drinking, and with the increased availability and use of energy-yielding beverages that have low satiety properties, can promote positive energy balance. There are marked individual differences in mean daily hunger and thirst ratings with unknown implications for energy balance.

Can gut hormones control appetite and prevent obesity?

The current obesity epidemic is fuelled by the availability of highly palatable, calorie-dense food, and the low requirement for physical activity in our modern environment. If energy intake exceeds energy use, the excess calories are stored as body fat. Although the body has mechanisms that act to maintain body weight over time, they primarily defend against starvation and are less robust in preventing the development of obesity. Knowledge of this homeostatic system that controls body weight has increased exponentially over the last decade and has revealed new possibilities for the treatment of obesity and its associated comorbidities. One therapeutic target is the development of agents based on the gastrointestinal hormones that control appetite. This review discusses the hormones oxyntomodulin, peptide YY, glucagon-like peptide 1, pancreatic polypeptide, and ghrelin and their emerging potential as anti-obesity treatments.

Role of obesity on the risk for total hip or knee arthroplasty

We asked whether there was an association between obesity levels and subsequent THA or TKA using data from 54,406 THA and TKA patients entered into the Canadian Joint Replacement Registry. We compared these patients with a sample of the Canadian population using the Canadian Community Health Survey of 2006. We analyzed information from the Canadian Joint Replacement Registry to quantify the relative risk for THA or TKA in Canada for specific body mass index categories. In reference to the acceptable weight category of body mass index less than 25 kg/m2, the risk for TKA and THA was 3.20- and 1.92-fold higher, respectively, for overweight individuals (body mass index 25-29.9 kg/m2); 8.53- (TKA) and 3.42-fold (THA) higher for those in the obese Class I (body mass index 30-34.9 kg/m2) category; 18.73- (TKA) and 5.24-fold (THA) higher for those identified in obese Class II (body mass index 35-39.9 kg/m2); and 32.73- (TKA) and 8.56-fold (THA) higher for people in obese Class III group (body mass index > 40 kg/m2). Thus, our data support an association between obesity and subsequent THA and TKA.

Leptina e exercício físico aeróbio: implicações da adiposidade corporal e insulina

Atualmente, a obesidade pode ser classificada como uma pandemia e suas conseqüências vão desde o diabetes mellitus até a doença cardíaca. Tanto fatores genéticos como ambientais contribuem para isso, porém, em humanos, o componente genético ainda é pouco definido. Com a clonagem do gene ob de ratos e do seu receptor, foi descoberta a leptina, o "hormônio da saciedade". A leptina é secretada, principalmente, pelo tecido adiposo e reflete a quantidade de gordura depositada no tecido adiposo de um indivíduo. Entretanto, diversos fatores influenciam sua expressão e síntese, tais como jejum, atividade simpática, exercício físico e alterações no balanço energético. Os efeitos da atividade física aeróbia sobre esse hormônio ainda não estão muito claros, visto que existem muitas contradições na literatura sobre sua possível ação na regulação da leptina. Estudos transversais sugerem que as concentrações plasmáticas de leptina não são alteradas após uma sessão de exercício aeróbio. Entretanto, se o esforço físico for extremo, como em uma ultramaratona, na qual há um balanço energético negativo, induzido pela atividade física extenuante, ocorre diminuição dessas concentrações. Além disso, exercícios de longa duração (> 60 min) parecem estar associados à diminuição tardia das concentrações de leptina, aproximadamente 48h após a atividade, provavelmente em função de um possível desequilíbrio energético. Em relação aos estudos longitudinais, após o treinamento aeróbio, alguns autores não observam alterações na leptina plasmática, outros encontram alterações em função apenas das alterações da adiposidade e, por fim, alguns estudos observam diminuição da concentração plasmática e/ou expressão de leptina, independentemente de alterações da massa gorda. Tal fato sugere que haja outro, ou outros, fatores, além do conteúdo de gordura corporal, que modulam a diminuição das concentrações plasmáticas de leptina após o treinamento aeróbio, sendo a insulina a principal candidata a tal modulação. Dessa forma, esta revisão aborda os principais aspectos do hormônio leptina, sua ação, função e regulação, associação com a insulina, além dos efeitos do exercício físico agudo e crônico na síntese e secreção da leptina, e possíveis implicações da insulina e adiposidade em função desse estímulo.

Association analysis of vitamin D-binding protein gene polymorphisms with variations of obesity-related traits in Caucasian nuclear families

BACKGROUND

Vitamin D-binding protein (DBP) gene is well known for its function on glucose and vitamin D metabolism in human populations. Previous studies suggested that the in vivo DBP level may play a role in the etiology of obesity. However, few studies explored the contribution of DBP gene to the variance of obesity phenotypes.

OBJECTIVE

To investigate the relationship of DBP polymorphisms and obesity in Caucasian nuclear families.

DESIGN

We genotyped 14 single-nucleotide polymorphisms (SNPs) located in and around the DBP gene in 1873 Caucasian subjects from 405 nuclear families. Three obesity-related quantitative phenotypes were investigated, including body mass index (BMI), fat mass and percentage of fat mass (PFM). Single SNPs and haplotypes (three blocks) were tested by family-based association using the FBAT software.

RESULTS

SNP2 (rs17467825) and its corresponding haplotype GAA (frequency 0.270) in block 1 showed strongest associations with PFM (P=0.0011 and 0.0023, respectively). In multivariate test significant association was also observed for SNP2 with fat mass&BMI&PFM (P=0.0098). Subsequent sex-stratified analyses demonstrated nominal association for SNP2 and haplotype GAA with PFM in the female subgroup.

CONCLUSION

Polymorphisms of DBP gene were significantly association with human PFM, especially in female, suggesting the importance of DBP gene in the pathogenesis of human obesity.

Effects of Intended Weight Loss on Morbidity and Mortality: Possible Explanations of Controversial Results

Long-term, population-based, observational studies have shown that intended weight loss does not always reduce the mortality associated with obesity. The effects of weight loss on mortality may be a balance between the effects of the loss of harmful abdominal and ectopic fat mass and the loss of beneficial peripheral subcutaneous fat mass and lean body mass.

Cardiovascular disease, metabolic syndrome and erectile dysfunction

PURPOSE OF REVIEW

Erectile dysfunction and cardiovascular disease share the same risk factors such as hypertension, diabetes, dyslipidemia, obesity, and smoking, all of which are implicated in causing endothelial dysfunction. In this review, an overview is given on the role of endothelium in the pathophysiology of erectile dysfunction, cardiovascular disease, and the metabolic syndrome as well as the links between them.

RECENT FINDINGS

Current literature offers strong evidence that endothelial dysfunction and erectile dysfunction are linked. Erectile dysfunction appears to be one of the earliest signs of systemic vascular disease and might be considered as an early marker for subclinical cardiovascular disease. Obesity is one of the many risk factors for cardiovascular disease and is also associated with hypertension, dyslipidemia, glucose intolerance, and insulin resistance, which together define the metabolic syndrome. Experimental, clinical, and epidemiologic studies support the association between metabolic syndrome and cardiovascular disease.

SUMMARY

The above-mentioned risk factors are a potential threat to the penile endothelium and the smooth muscle tissue leading to functional and structural changes. These important pathophysiologic factors are the foundation for the strong link between erectile dysfunction and cardiovascular disease. Recent literature supports the link between metabolic syndrome and erectile dysfunction and highlights metabolic syndrome as a potential risk factor for the development of erectile dysfunction.

Effect of prepregnancy body mass index categories on obstetrical and neonatal outcomes

OBJECTIVES

To examine the association between body mass index (BMI) and obstetrical and neonatal outcomes.

METHODS

We conducted a cohort study comparing prepregnant BMI categories with obstetrical and neonatal outcomes using the McGill Obstetrical and Neonatal Database on all deliveries in 10 year period (1987-1997). Prepregnant BMI was categorized into underweight (<20), normal (20-24.9), overweight (25-29.9), obese (30-39.9), and morbidly obese (40+). Logistic regression analysis was used to adjust for age, smoking, parity, and preexisting diabetes using normal BMI as the reference.

RESULTS

The population consisted of underweight 4,312 (23.1%), normal weight 10,021 (53.8%), overweight 3,069 (16.5%), obese 1,137 (6.1%), and morbidly obese 104 (0.6%). As compared to women with normal BMIs, overweight, obese, and morbidly obese women had an increased risk of preeclampsia 2.28 (1.88-2.77), 4.65 (3.71-5.83), 6.26 (3.48-11.26); gestational hypertension 1.56 (1.35-1.81), 2.01 (1.64-2.45), 2.77 (1.60-4.78); gestational diabetes 1.89 (1.63-2.19), 3.22 (2.68-3.87), 4.71 (2.89-7.67); preterm birth 1.20 (1.04-1.38), 1.60 (1.32-1.94), 2.43 (1.46-4.05); cesarean section 1.48 (1.35-1.62), 1.85 (1.62-2.11), 2.92 (1.97-4.34); and macrosomia 1.66 (1.23-2.24), 2.32 (1.58-3.41), 2.10 (0.64-6.86). Underweight women were less likely to have: preeclampsia 0.67 (0.52-0.86), gestational hypertension 0.71 (0.60-0.83), gestational diabetes 0.82 (0.69-0.97), cesarean section 0.89 (0.81-0.97), shoulder dystocia 0.88 (0.80-0.96), birth injuries 0.40 (0.21-0.77), and macrosomia 0.43 (0.28-0.68) but more likely to have small for gestational age infants 1.54 (1.37-1.72) and intrauterine growth restricted infants 1.33 (1.07-1.67).

CONCLUSION

In a large Canadian teaching hospital, increasing prepregnancy BMI category was associated with an increasing risk of adverse pregnancy outcomes. Underweight prepregnancy BMI was associated with a reduced risk of adverse pregnancy outcomes.

REPORT: Obesity, Dyslipidemias and Erectile Dysfunction: A Report of a Subcommittee of the Sexual Medicine Society of North America

Because of increasingly sedentary lifestyles and diets higher in saturated fats, obesity and dyslipidemias are common and increasing in prevalence in Westernized countries. Longitudinal population-based studies clearly demonstrate that dyslipidemias and obesity, as well as factors such as hypertension, diabetes, and smoking, are major risk factors for atherosclerosis. Both clinical and animal models of endothelial dysfunction confirm that atherosclerosis leads to increased cerebrovascular and cardiovascular morbidity. Clinical studies with hypolipidemic agents demonstrate that hydroxy-3-methylglutaryl coenzyme A reductase inhibitors can decrease the risk of vascular morbidity. An increasing body of evidence from animal models demonstrates that hypercholesterolemia and atherosclerosis are risk factors for the development of erectile dysfunction (ED). This causal relationship between obesity and dyslipidemias with the development of ED in humans still needs further definition with convincing peer-reviewed scientific studies. The challenge for the future will be to define the benefit of controlling obesity and dyslipidemias on the development of ED and improvement of erectile function.

Intensive weight loss program improves physical function in older obese adults with knee osteoarthritis

OBJECTIVE

Physical function and body composition in older obese adults with knee osteoarthritis (OA) were examined after intensive weight loss.

RESEARCH METHODS AND PROCEDURES

Older obese adults (n = 87; > or = 60 years; BMI > or = 30.0 kg/m2) with symptomatic knee OA and difficulty with daily activities were recruited for a 6-month trial. Participants were randomized into either a weight stable (WS) or weight loss (WL) program. Participants in WL (10% weight loss goal) were prescribed a 1000 kcal/d energy deficit diet with exercise 3 d/wk. WS participants attended health information sessions. Body composition and physical function (Western Ontario and McMaster University Osteoarthritis Index, 6-minute walking distance, and stair climb time) were assessed at baseline and 6 months. Statistical analysis included univariate analysis of covariance on 6-month measurements using baseline values as covariates. Associations between physical function and body composition were performed.

RESULTS

Body weight decreased 8.7 +/- 0.8% in WL and 0.0 +/- 0.7% in WS. Body fat and fat-free mass were lower for WL than WS at 6 months (estimated means: fat = 38.1 +/- 0.4% vs. 40.9 +/- 0.4%, respectively; fat-free mass = 56.7 +/- 0.4 vs. 58.8 +/- 0.4 kg, respectively). WL had better function than WS, with lower Western Ontario and McMaster University Osteoarthritis Index scores, greater 6-minute walk distance, and faster stair climb time (p < 0.05). Changes in function were associated with weight loss in the entire cohort.

DISCUSSION

An intensive weight loss intervention incorporating energy deficit diet and exercise training improves physical function in older obese adults with knee OA. Greater improvements in function were observed in those with the most weight loss.

Obesity: America’s Epidemic

The health risks of overweight and obesity have been well documented. For example, even a 15-lb. weight gain increases a person's risk of diabetes by 50%. In turn, losing as little as 11 lbs. can reduce a person's risk of diabetes by the same percentage. Why, then, aren't more Americans losing weight? This article explores the rising incidence of overweight and obesity in the United States, the reasons so many people fail to lose weight or maintain a weight loss, and the potential for nurses to turn the tide on this epidemic.

Obesity and weight control practices in 2000 among veterans using VA facilities

OBJECTIVE

To examine obesity prevalence and weight control practices among veterans who use Department of Veterans Affairs (VA) medical facilities (VA users).

RESEARCH METHODS AND PROCEDURES

Data from the 2000 Behavioral Risk Factor Surveillance System, a telephone survey of 184,450 adults, were analyzed. Outcome measures included BMI, weight control practices (the intent to manage weight, and diet and physical activity patterns), and receipt of professional weight control advice.

RESULTS

Of VA users, 44% were overweight and 25% were obese. After controlling for demographic factors, VA users were somewhat less likely to be overweight (odds ratio, 0.86; 95% confidence interval, 0.74 to 1.00) but equally likely to be obese (odds ratio, 1.08; 95% confidence interval, 0.92 to 1.27), compared with non-VA users. Among obese VA users, 75% reported trying to lose weight, and another 17% reported trying to maintain weight. Of these, only 40% decreased both calorie and fat intake. Only 27% of obese VA users who reported increasing exercise to lose weight followed recommendations for regular and sustained physical activity. Of obese VA users, 59% were inactive or irregularly active. Only 51% of obese VA users received professional advice to lose weight. Obese VA users were more likely than obese non-VA users to report trying to lose weight, modifying diet to lose weight by decreasing both calories and fat intake, and receiving professional weight control advice.

DISCUSSION

Interventions for weight management programs in VA facilities need to take into account the high prevalence of overweight/obesity among VA users and should emphasize effective weight control practices.

Gender-specific association of a perilipin gene haplotype with obesity risk in a white population

OBJECTIVE

Perilipin is a class of protein-coating lipid droplets in adipocytes and steroidogenic cells. Our purpose was to examine the association between common single-nucleotide polymorphisms (SNPs) at the perilipin (PLIN) locus and obesity, as well as related phenotypes, in unrelated American adults.

RESEARCH METHODS AND PROCEDURES

Four PLIN SNPs (PLIN 6209T>C, 11482G>A, 13041A>G, and 14995A>T) were typed in 734 white subjects (373 men and 361 women) attending a residential lifestyle intervention program. The baseline anthropometric and biochemical measures were used. Obesity was defined as BMI > or = 30 kg/m(2).

RESULTS

Multivariate analysis demonstrated that, in women, two of the SNPs (13041A>G, and 14995A>T) were significantly associated with percentage body fat (p = 0.016 for 13041A>G and p = 0.010 for 14995A>T) and waist circumference (p = 0.020 for 13041A>G and p = 0.045 for 14995A>T). Moreover, haplotype analysis using these two SNPs indicated that haplotypes A/T and G/T were both associated with significantly increased obesity risk (odds ratio = 1.76, 95% confidence interval 1.07 to 2.90 for haplotype A/T, and odds ratio = 1.73, 95% confidence interval 1.06 to 2.82 for haplotype G/T) when compared with haplotype A/A. No significant associations between PLIN variations and obesity were found in men.

DISCUSSION

Our data support the hypothesis that the PLIN locus may be a significant genetic determinant for obesity risk in whites and that women are more sensitive to the genetic effects of perilipin than men.

Weight and weight concerns: are they associated with reported depressive symptoms in adolescents?

INTRODUCTION

The primary purpose of this study was to examine the incidence of obesity, perception of weight, and weight management behaviors in a nationwide sample of adolescents. Further, the relationship between these variables and the adolescents' self-reported depressive symptoms was also explored.

METHOD

Cross-sectional data from 16- to 18-year-olds who participated in the 1999 (n=9795) and 2001 (n=8190) Youth Risk Behavioral Surveillance System were used for this secondary analysis.

RESULTS

No relationship was found between depressive symptoms and body mass index. However, perception of weight as either underweight or overweight was related to higher depressive symptoms. The risk profile for reporting depressive symptoms includes use of any weight control strategies, female, and perception of weight.

DISCUSSION

These findings underscore the importance of addressing adolescents' perceptions of weight in relation to their actual body mass index and psychological well-being.

Identification of Barrett's esophagus in relatives by endoscopic screening

AIM

Familial aggregation of Barrett's esophagus and its associated cancers has been termed familial Barrett's esophagus (FBE). The aim of the study was to determine whether endoscopic screening would identify Barrett's esophagus (BE) in relatives of probands with BE or esophageal adenocarcinoma (EAC).

METHODS

All living first-degree relatives of patients with long segment BE or EAC presenting to the endoscopy suite of two academic hospitals were sent validated questionnaires inquiring about gastroesophageal reflux symptoms and prior endoscopic evaluation. First-degree relatives of affected probands or affected relatives who reported no prior upper endoscopy were offered screening unsedated esophagoscopy. Relatives with chronic gastroesophageal reflux symptoms were also offered an alternative of conventional sedated upper endoscopy. The yield of screening endoscopy was measured. Screening endoscopy findings were then compared between family members of known FBE patients and those with "isolated" disease.

RESULTS

One hundred and ninety-eight relatives from 69 families, 23 known FBE probands and 46 probands with apparently "isolated" disease, were enrolled. Forty relatives (29 FBE relatives and 11 relatives of probands with "isolated" disease) reported prior upper endoscopy. Screening upper endoscopies performed on 62 (25 FBE and 37 "isolated" disease relatives) of the remaining 158 relatives identified Barrett's epithelium in 13 (21%). Compared to probands with apparently "isolated" disease, Barrett's epithelium (EAC, BE, or SSBE) was identified significantly more often in siblings and offspring of FBE probands, p</= 0.05. Endoscopic screening of relatives of FBE probands identified a multigeneration multiplex FBE pedigree consistent with an autosomally dominant inherited trait. Endoscopic screening of relatives of probands with reported "isolated" diseased did not identify any new FBE pedigrees.

CONCLUSIONS

Endoscopy identified EAC, long-segment BE, and short-segment BE in a substantial proportion of first-degree relatives of affected members of FBE families. A familial susceptibility to develop Barrett's epithelium appears to be present in a subset of patients with BE and EAC.

Effects of promotional materials on vending sales of low-fat items in teachers' lounges

This study examined the impact of an environmental intervention in the form of promotional materials and increased availability of low-fat items on vending machine sales. Ten vending machines were selected and randomly assigned to one of three conditions: control, or one of two experimental conditions. Vending machines in the two intervention conditions received three additional low-fat selections. Low-fat items were promoted at two levels: labels (intervention I), and labels plus signs (intervention II). The number of individual items sold and the total revenue generated was recorded weekly for each machine for 4 weeks. Use of promotional materials resulted in a small, but not significant, increase in the number of low-fat items sold, although machine sales were not significantly impacted by the change in product selection. Results of this study, although not statistically significant, suggest that environmental change may be a realistic means of positively influencing consumer behavior.

What role for weight-loss medication? Weighing the pros and cons for obese patients

Obesity is a chronic medical disorder that is not going away anytime soon. Physicians need all the education, tools, and resources possible to successfully help their overweight and obese patients. Weight-loss medications alone are clearly not the answer. However, they are one tool physicians can use in combination with lifestyle changes to increase the success of long-term weight loss in selected patients.

The prevalence of obesity

During the past several decades, obesity has increased substantially, making it a true epidemic and a public health crisis that both health care providers and the public are going to have to face. Currently, 61% of the US population is overweight or obese and therefore at increased risk for a number of diseases that are associated with increased body fat. Indeed, the obesity epidemic already is leading to dramatic increases in type 2 diabetes and the metabolic syndrome. Almost a quarter of the population currently has metabolic syndrome, which places them at high risk for the development of coronary heart disease. The future of the general health of the US population depends on identifying and providing the best treatment and prevention strategies for obesity in the years ahead.

Physical activity levels among overweight and obese adults in South Carolina

BACKGROUND

Obesity in the United States has reached epidemic proportions and is a major cause of morbidity and mortality.

METHODS

We describe the activity levels of South Carolina adults on the basis of data derived from the Centers for Disease Control and Prevention Behavioral Risk Factor Surveillance System.

RESULTS

Overweight and obese men and women reported less leisure time physical activity than did people of normal weight, with women found to be less active than men.

CONCLUSION

Physical inactivity is more prevalent among obese and overweight men and women than among people of normal weight. Visiting the physician's office offers a unique opportunity to educate patients about the health benefits and appropriate amount of physical activity.

Obstructive sleep apnea and the recurrence of atrial fibrillation

BACKGROUND

We tested the hypothesis that patients with untreated obstructive sleep apnea (OSA) would be at increased risk for recurrence of atrial fibrillation (AF) after cardioversion.

METHODS AND RESULTS

We prospectively obtained data on history, echocardiogram, ECG, body mass index, hypertension, diabetes, NYHA functional class, ejection fraction, left atrial appendage velocity, and medications in patients with AF/atrial flutter referred for DC cardioversion. Forty-three individuals were identified as having OSA on the basis of a previous sleep study. Data regarding the use of continuous positive airway pressure (CPAP) and recurrence of AF were obtained for 39 of these patients. Follow-up data were also obtained in 79 randomly selected postcardioversion patients (controls) who did not have any previous sleep study. Twenty-seven of the 39 OSA patients either were not receiving any CPAP therapy (n=25) or were using CPAP inappropriately (n=2). Recurrence of AF at 12 months in these 27 patients was 82%, higher than the 42% recurrence in the treated OSA group (n=12, P=0.013) and the 53% recurrence (n=79, P=0.009) in the 79 control patients. Of the 25 OSA patients who had not been treated at all, the nocturnal fall in oxygen saturation was greater (P=0.034) in those who had recurrence of AF (n=20) than in those without recurrence (n=5).

CONCLUSIONS

Patients with untreated OSA have a higher recurrence of AF after cardioversion than patients without a polysomnographic diagnosis of sleep apnea. Appropriate treatment with CPAP in OSA patients is associated with lower recurrence of AF.