Showing papers in "Obesity Reviews in 2013"

Ultra‐processed products are becoming dominant in the global food system

Abstract: The relationship between the global food system and the worldwide rapid increase of obesity and related diseases is not yet well understood. A reason is that the full impact of industrialized food processing on dietary patterns, including the environments of eating and drinking, remains overlooked and underestimated. Many forms of food processing are beneficial. But what is identified and defined here as ultra-processing, a type of process that has become increasingly dominant, at first in high-income countries, and now in middle-income countries, creates attractive, hyper-palatable, cheap, ready-to-consume food products that are characteristically energy-dense, fatty, sugary or salty and generally obesogenic. In this study, the scale of change in purchase and sales of ultra-processed products is examined and the context and implications are discussed. Data come from 79 high- and middle-income countries, with special attention to Canada and Brazil. Results show that ultra-processed products dominate the food supplies of high-income countries, and that their consumption is now rapidly increasing in middle-income countries. It is proposed here that the main driving force now shaping the global food system is transnational food manufacturing, retailing and fast food service corporations whose businesses are based on very profitable, heavily promoted ultra-processed products, many in snack form.

Resolved: there is sufficient scientific evidence that decreasing sugar-sweetened beverage consumption will reduce the prevalence of obesity and obesity-related diseases

Abstract: Summary Sugar-sweetened beverages (SSBs) are the single largest source of added sugar and the top source of energy intake in the U.S. diet. In this review, we evaluate whether there is sufficient scientific evidence that decreasing SSB consumption will reduce the prevalence of obesity and its related diseases. Because prospective cohort studies address dietary determinants of long-term weight gain and chronic diseases, whereas randomized clinical trials (RCTs) typically evaluate short-term effects of specific interventions on weight change, both types of evidence are critical in evaluating causality. Findings from well-powered prospective cohorts have consistently shown a significant association, established temporality and demonstrated a direct dose‐response relationship between SSB consumption and long-term weight gain and risk of type 2 diabetes (T2D). A recently published meta-analysis of RCTs commissioned by the World Health Organization found that decreased intake of added sugars significantly reduced body weight (0.80 kg, 95% confidence interval [CI] 0.39‐1.21; P < 0.001), whereas increased sugar intake led to a comparable weight increase (0.75 kg, 0.30‐1.19; P = 0.001). A parallel meta-analysis of cohort studies also found that higher intake of SSBs among children was associated with 55% (95% CI 32‐82%) higher risk of being overweight or obese compared with those with lower intake. Another metaanalysis of eight prospective cohort studies found that one to two servings per day of SSB intake was associated with a 26% (95% CI 12‐41%) greater risk of developing T2D compared with occasional intake (less than one serving per month). Recently, two large RCTs with a high degree of compliance provided convincing data that reducing consumption of SSBs significantly decreases weight gain and adiposity in children and adolescents. Taken together, the evidence that decreasing SSBs will decrease the risk of obesity and related diseases such as T2D is compelling. Several additional issues warrant further discussion. First, prevention of long-term weight gain through dietary changes such as limiting consumption of SSBs is more important than short-term weight loss in reducing the prevalence of obesity in the population. This is due to the fact that once an individual becomes obese, it is difficult to lose weight and keep it off. Second, we should consider the totality of evidence rather than selective pieces of evidence (e.g. from short-term RCTs only). Finally, while recognizing that the evidence of harm on health against SSBs is strong, we should avoid the trap of waiting for absolute proof before allowing public health action to be taken.

Obesity and addiction: neurobiological overlaps.

Abstract: Drug addiction and obesity appear to share several properties. Both can be defined as disorders in which the saliency of a specific type of reward (food or drug) becomes exaggerated relative to, and at the expense of others rewards. Both drugs and food have powerful reinforcing effects, which are in part mediated by abrupt dopamine increases in the brain reward centres. The abrupt dopamine increases, in vulnerable individuals, can override the brain's homeostatic control mechanisms. These parallels have generated interest in understanding the shared vulnerabilities between addiction and obesity. Predictably, they also engendered a heated debate. Specifically, brain imaging studies are beginning to uncover common features between these two conditions and delineate some of the overlapping brain circuits whose dysfunctions may underlie the observed deficits. The combined results suggest that both obese and drug-addicted individuals suffer from impairments in dopaminergic pathways that regulate neuronal systems associated not only with reward sensitivity and incentive motivation, but also with conditioning, self-control, stress reactivity and interoceptive awareness. In parallel, studies are also delineating differences between them that centre on the key role that peripheral signals involved with homeostatic control exert on food intake. Here, we focus on the shared neurobiological substrates of obesity and addiction.

Obesity and C-reactive protein in various populations: a systematic review and meta-analysis

Abstract: Obesity has been associated with elevated levels of C-reactive protein (CRP), a marker of inflammation and predictor of cardiovascular risk. The objective of this systematic review and meta-analysis was to estimate the associations between obesity and CRP according to sex, ethnicity and age. MEDLINE and EMBASE databases were searched through October 2011. Data from 51 cross-sectional studies that used body mass index (BMI), waist circumference (WC) or waist-to-hip ratio (WHR) as measure of obesity were independently extracted by two reviewers and aggregated using random-effects models. The Pearson correlation (r) for BMI and ln(CRP) was 0.36 (95% confidence interval [CI], 0.30-0.42) in adults and 0.37 (CI, 0.31-0.43) in children. In adults, r for BMI and ln(CRP) was greater in women than men by 0.24 (CI, 0.09-0.37), and greater in North Americans/Europeans than Asians by 0.15 (CI, 0-0.28), on average. In North American/European children, the sex difference in r for BMI and ln(CRP) was 0.01 (CI, -0.08 to 0.06). Although limited to anthropometric measures, we found similar results when WC and WHR were used in the analyses. Obesity is associated with elevated levels of CRP and the association is stronger in women and North Americans/Europeans. The sex difference only emerges in adulthood.

Assessing the potential effectiveness of food and beverage taxes and subsidies for improving public health: a systematic review of prices, demand and body weight outcomes

Abstract: Taxes and subsidies are increasingly being considered as potential policy instruments to incentivize consumers to improve their food and beverage consumption patterns and related health outcomes. This study provided a systematic review of recent U.S. studies on the price elasticity of demand for sugar-sweetened beverages (SSBs), fast food and fruits and vegetables as well as the direct associations of prices/taxes with body weight outcomes. Based on the recent literature, the price elasticity of demand for SSBs, fast food, fruits and vegetables was estimated to be −1.21, −0.52, −0.49 and −0.48, respectively. The studies that linked soda taxes to weight outcomes showed minimal impacts on weight; however, they were based on existing state-level sales taxes that were relatively low. Higher fast-food prices were associated with lower weight outcomes particularly among adolescents suggesting that raising prices would potentially impact weight outcomes. Lower fruit and vegetable prices were generally found to be associated with lower body weight outcomes among both low-income children and adults suggesting that subsidies that would reduce the cost of fruits and vegetables for lower-socioeconomic populations may be effective in reducing obesity. Pricing instruments should continue to be considered and evaluated as potential policy instruments to address public health risks.

INFORMAS (International Network for Food and Obesity/non-communicable diseases Research, Monitoring and Action Support): overview and key principles

Abstract: 20 Global Alliance for Improved Nutrition (GAIN), Geneva, Switzerland Summary Non-communicable diseases (NCDs) dominate disease burdens globally and poor nutrition increasingly contributes to this global burden. Compre- hensive monitoring of food environments, and evaluation of the impact of public and private sector policies on food environments is needed to strengthen accountability systems to reduce NCDs. The International Network for Food and Obesity/NCDs Research, Monitoring and Action Support (INFORMAS) is a global network of public-interest organizations and researchers that aims to monitor, benchmark and support public and private sector actions to create healthy food environments and reduce obesity, NCDs and their related inequalities. The INFORMAS framework includes two 'process' modules, that monitor the policies and actions of the public and private sectors, seven 'impact' modules that monitor the key characteristics of food environments and three 'outcome' modules that monitor dietary quality, risk factors and NCD morbidity and mortality. Monitoring frameworks and indicators have been developed for 10 modules to provide consistency, but allowing for stepwise approaches ('minimal', 'expanded', 'optimal') to data collection and analysis. INFORMAS data will enable benchmarking of food environments between countries, and monitoring of progress over time within countries. Through monitoring and benchmarking, INFORMAS will strengthen the account- ability systems needed to help reduce the burden of obesity, NCDs and their related inequalities.

The effect of obesity on polycystic ovary syndrome: a systematic review and meta-analysis

Abstract: While many women with polycystic ovary syndrome (PCOS) are overweight, obese or centrally obese, the effect of excess weight on the outcomes of PCOS is inconsistent. The review aimed to assess the effects of overweight, obesity and central obesity on the reproductive, metabolic and psychological features of PCOS. MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL) and PSYCINFO were searched for studies reporting outcomes according to body mass index categories or body fat distribution. Data were presented as mean difference or risk ratio (95% confidence interval). This review included 30 eligible studies. Overweight or obese women with PCOS had decreased sex hormone-binding globulin (SHBG), increased total testosterone, free androgen index, hirsutism, fasting glucose, fasting insulin, homeostatic model assessment-insulin resistance index and worsened lipid profile. Obesity significantly worsened all metabolic and reproductive outcomes measured except for hirsutism when compared to normal weight women with PCOS. Overweight women had no differences in total testosterone, hirsutism, total-cholesterol and low-density lipoprotein-cholesterol compared to normal weight women and no differences in SHBG and total testosterone compared to obese women. Central obesity was associated with higher fasting insulin levels. These results suggest that prevention and treatment of obesity is important for the management of PCOS.

Food‐related impulsivity in obesity and Binge Eating Disorder – a systematic review

Abstract: Impulsivity towards food has been recognized as a potential factor leading to increased food intake in obesity. Patients suffering from binge eating disorder (BED) form a specific subgroup of obese people that might be characterized by increased impulsivity. These assumptions, although, have yet to be verified. Therefore, this review evaluates evidence for food-related impulsivity in obese people with and without BED and examines possible differences between both populations. More precisely, evidence for the two components of impulsivity is analyzed separately: evidence for reward sensitivity, specifically, the urge for appetitive stimuli and evidence for rash-spontaneous behaviour such as acting disinhibited with no regard for the consequences. Our search resulted in 51 articles demonstrating generally increased food-related impulsivity. We found particular emphasis on increased reward sensitivity in obese people, which appeared to be more pronounced in people with BED. There was little and conflicting evidence, however, concerning increased rash-spontaneous behaviour in obese people without BED, but consistent evidence of an increase in obese people with BED. All in all, the evidence supports the view that BED represents a specific phenotype of obesity with increased food-related impulsivity. Taking these specific deficits into account can enhance the effectiveness of weight reduction programmes and psychotherapy.

Educational attainment and obesity: a systematic review

Abstract: Although previous systematic reviews considered the relationship between socioeconomic status and obesity, almost 200 peer-reviewed articles have been published since the last review on that topic, and this paper focuses specifically on education, which has different implications. The authors systematically review the peer-reviewed literature from around the world considering the association between educational attainment and obesity. Databases from public health and medicine, education, psychology, economics, and other social sciences were searched, and articles published in English, French, Portuguese and Spanish were included. This paper includes 289 articles that report on 410 populations in 91 countries. The relationship between educational attainment and obesity was modified by both gender and the country's economic development level: an inverse association was more common in studies of higher-income countries and a positive association was more common in lower-income countries, with stronger social patterning among women. Relatively few studies reported on lower-income countries, controlled for a comprehensive set of potential confounding variables and/or attempted to assess causality through the use of quasi-experimental designs. Future research should address these gaps to understand if the relationship between educational attainment and obesity may be causal, thus supporting education policy as a tool for obesity prevention.

A food policy package for healthy diets and the prevention of obesity and diet-related non-communicable diseases: the NOURISHING framework

Abstract: This paper presents the NOURISHING framework of food policies to promote healthy diets, and uses the framework to summarize the policy actions taken by the Bellagio meeting countries. NOURISHING was developed by WCRF International to formalize a comprehensive policy package that brings together the key domains of action and policy areas. It aims to provide global level recommendations for a comprehensive response, within which policymakers have the flexibility to select specific policy options suitable for their national/local contexts and target populations. It also aims to provide a framework for reporting, categorizing and monitoring policy actions taken around the world, and for systematically categorizing, updating, interpreting and communicating the evidence for policy to policymakers. In this paper we explain the structure for NOURISHING and the rationale behind it. We also use the framework to report on and categorize the policy actions implemented in the Bellagio countries.

Daily physical activity assessment with accelerometers: new insights and validation studies

Abstract: The field of application of accelerometry is diverse and ever expanding. Because by definition all physical activities lead to energy expenditure, the doubly labelled water (DLW) method as gold standard to assess total energy expenditure over longer periods of time is the method of choice to validate accelerometers in their ability to assess daily physical activities. The aim of this paper was to provide a systematic overview of all recent (2007-2011) accelerometer validation studies using DLW as the reference. The PubMed Central database was searched using the following keywords: doubly or double labelled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. Limits were set to include articles from 2007 to 2011, as earlier publications were covered in a previous review. In total, 38 articles were identified, of which 25 were selected to contain sufficient new data. Eighteen different accelerometers were validated. There was a large variability in accelerometer output and their validity to assess daily physical activity. Activity type recognition has great potential to improve the assessment of physical activity-related health outcomes. So far, there is little evidence that adding other physiological measures such as heart rate significantly improves the estimation of energy expenditure.

Is food addiction a valid and useful concept

Abstract: In this paper, we consider the concept of food addiction from a clinical and neuroscientific perspective. Food addiction has an established and growing currency in the context of models of overeating and obesity, and its acceptance shapes debate and research. However, we argue that the evidence for its existence in humans is actually rather limited and, in addition, there are fundamental theoretical difficulties that require consideration. We therefore review food addiction as a phenotypic description, one that is based on overlap between certain eating behaviours and substance dependence. To begin, we consider limitations in the general application of this concept to obesity. We share the widely held view that such a broad perspective is not sustainable and consider a more focused view: that it underlies particular eating patterns, notably binge eating. However, even with this more specific focus, there are still problems. Validation of food addiction at the neurobiological level is absolutely critical, but there are inconsistencies in the evidence from humans suggesting that caution should be exercised in accepting food addiction as a valid concept. We argue the current evidence is preliminary and suggest directions for future work that may provide more useful tests of the concept.

Structural responses to the obesity and non-communicable diseases epidemic: the Chilean Law of Food Labeling and Advertising.

Abstract: In 12 July 2012, the Chilean Senate approved the Law of Food Labeling and Advertising, resulting from the joint efforts of a group of health professionals, researchers and legislators who proposed a regulatory framework in support of healthy diets and active living. Its goal was to curb the ongoing epidemic increase of obesity and non-communicable diseases. Two actions included: (i) improving point of food purchase consumer information by incorporating easy-to-understand front-of-packages labeling and specific messages addressing critical nutrients, and (ii) decreasing children's exposure to unhealthy foods by restricting marketing, advertising and sales. We summarize the work related to the law's release and discuss the conclusions reached by the various expert committees that were convened by the Ministry of Health to guide the development of the regulatory norms. Throughout the process, the food industry has overtly expressed its disagreement with the regulatory effort. The final content of the regulatory norms is still pending; however there are suggestions that its implementation will be delayed and might be modified based on the industry lobbying actions. These lessons should contribute to show the need of anticipating and addressing potential barriers to obesity-prevention policy implementation, particularly with respect to the role of the private sector.

New dynamics in global obesity facing low- and middle-income countries.

Abstract: Levels of overweight and obesity across low- and middle-income countries (LMIC) have approached levels found in higher-income countries. This is particularly true in the Middle East and North Africa and in Latin America and the Caribbean. Using nationally representative samples of women aged 19-49, n = 815,609, this paper documents the annualized rate of increase of overweight from the first survey in early 1990 to the last survey in the present millennium. Overweight increases ranged from 0.31% per year to 0.92% per year for Latin America and the Caribbean and for the Middle East and North Africa, respectively. For a sample of eight countries, using quantile regression, we further demonstrate that mean body mass index (BMI) at the 95th percentile has increased significantly across all regions, representing predicted weight increases of 5-10 kg. Furthermore we highlight a major new concern in LMICs, documenting waist circumference increases of 2-4 cm at the same BMI (e.g. 25) over an 18-year period. In sum, this paper indicates growing potential for increased cardiometabolic problems linked with a large rightward shift in the BMI distribution and increased waist circumference at each BMI level.

A systematic review of variables associated with the relationship between obesity and depression.

Abstract: Summary Obesity is one of the leading causes of preventable diseases and disability worldwide, and depression is among the leading causes of burden of disease. Both disorders are increasingly prevalent and comorbid. This comorbidity compounds associated health. While there is consistent evidence of a bidirectional obesity depression relationship, little is known about the biopsychosocial variables associated with this relationship. A systematic review was undertaken to identify variables associated with the relationship between obesity (Body mass index > 30 kg m−2) and depression. Forty-six studies were identified. Obesity, educational attainment, body image, binge eating, physical health, psychological characteristics and interpersonal effectiveness were consistently associated with the relationship between obesity and depression. The current review identified potential biopsychosocial variables associated with the relationship between obesity and depression. This knowledge can inform future research examining moderators, mediators and mechanisms of the relationship between obesity and depression. Improved understanding of this relationship will inform identification, prevention and intervention efforts.

Towards an integrative approach to understanding the role of chemerin in human health and disease.

Abstract: Chemerin is an adipocyte-secreted protein with autocrine/paracrine roles on adipose development and function as well as endocrine roles in metabolism and immunity. Following prochemerin secretion, protease-mediated generation of chemerin isoforms with a range of biological activities is a key regulatory mechanism controlling local, context-specific chemerin bioactivity. Together, experimental and clinical data indicate that localized and/or circulating chemerin expression and activation are elevated in numerous metabolic and inflammatory diseases including psoriasis, obesity, type 2 diabetes, metabolic syndrome and cardiovascular disease. These elevations are positively correlated with deleterious changes in glucose, lipid, and cytokine homeostasis, and may serve as a link between obesity, inflammation and other metabolic disorders. This review highlights the current state of knowledge regarding chemerin expression, processing, biological function and relevance to human disease, particularly with respect to adipose tissue development, inflammation, glucose homeostasis and cardiovascular disease. Furthermore, it discusses study variability, deficiencies in current measurement, and questions concerning chemerin function in disease, with a special emphasis on techniques and tools used to properly assess chemerin biology. An integration of basic and clinical research is key to understanding how chemerin influences disease pathobiology, and whether modulation of chemerin levels and/or activity may serve as a potential method to prevent and treat metabolic diseases.

Association of obstructive sleep apnoea with the presence and severity of non-alcoholic fatty liver disease. A systematic review and meta-analysis.

Abstract: Summary Obstructive sleep apnoea syndrome (OSAS) and non-alcoholic fatty liver disease (NAFLD) are common in clinical practice. NAFLD encompasses simple steatosis and non-alcoholic steatohepatitis (NASH): both confer an increased risk of cardiovascular disease and diabetes; NASH increases also liver-related risk. Growing experimental evidence connects chronic intermittent hypoxia of OSAS to NAFLD. We reviewed English and non-English articles and international meeting abstracts through December 2012. Observational studies were included if they assessed OSAS by polysomnography and NAFLD by histological, radiological or biochemical criteria. Two reviewers evaluated retrieved articles by appropriate quality scores. Main outcomes were pooled using random- or fixed-effects models. The effect of age, sex and body mass index (BMI) on effect estimates was assessed by meta-regression. Eighteen cross-sectional studies (2,183 participants) were included. Pooled odds ratios (ORs) of OSAS for the presence of NAFLD, as defined by histology, radiology, and AST or ALT elevation, were 2.01(95% CI: 1.36–2.97), 2.99(1.79–4.99), 2.36(1.46–3.82) and 2.60(1.88–3.61), respectively. Pooled ORs of OSAS for NASH, fibrosis-any stage, or advanced fibrosis in biopsy-proven NAFLD patients were 2.37(1.59–3.51), 2.16(1.45–3.20) and 2.30(1.21–4.38). The magnitude and direction of effects were unaffected by age, sex and BMI. In conclusion, OSAS is associated with an increased risk of NAFLD, NASH and fibrosis. OSAS patients should be screened for the presence and severity of NAFLD.

Is butyrate the link between diet, intestinal microbiota and obesity-related metabolic diseases?

Abstract: It is increasingly recognized that there is a connection between diet, intestinal microbiota, intestinal barrier function and the low-grade inflammation that characterizes the progression from obesity to metabolic disturbances, making dietary strategies to modulate the intestinal environment relevant. In this context, the ability of some Gram-positive anaerobic bacteria to produce the short-chain fatty acid butyrate is interesting. A lower abundance of butyrate-producing bacteria has been associated with metabolic risk in humans, and recent studies suggest that butyrate might have an anti-inflammatory potential that can alleviate obesity-related metabolic complications, possibly due to its ability to enhance the intestinal barrier function. Here, we review and discuss the potential of butyrate as an anti-inflammatory mediator in metabolic diseases, and the potential for dietary interventions increasing the intestinal availability of butyrate.

Monitoring and benchmarking government policies and actions to improve the healthiness of food environments: a proposed Government Healthy Food Environment Policy Index.

Abstract: Government action is essential to increase the healthiness of food environments and reduce obesity, diet-related non-communicable diseases (NCDs), and their related inequalities. This paper proposes a monitoring framework to assess government policies and actions for creating healthy food environments. Recommendations from relevant authoritative organizations and expert advisory groups for reducing obesity and NCDs were examined, and pertinent components were incorporated into a comprehensive framework for monitoring government policies and actions. A Government Healthy Food Environment Policy Index (Food-EPI) was developed, which comprises a 'policy' component with seven domains on specific aspects of food environments, and an 'infrastructure support' component with seven domains to strengthen systems to prevent obesity and NCDs. These were revised through a week-long consultation process with international experts. Examples of good practice statements are proposed within each domain, and these will evolve into benchmarks established by governments at the forefront of creating and implementing food policies for good health. A rating process is proposed to assess a government's level of policy implementation towards good practice. The Food-EPI will be pre-tested and piloted in countries of varying size and income levels. The benchmarking of government policy implementation has the potential to catalyse greater action to reduce obesity and NCDs.

Bariatric surgery for obese children and adolescents: a systematic review and meta‐analysis

Abstract: Summary The number of obese young people continues to rise, with a corresponding increase in extreme obesity and paediatric-adolescent bariatric surgery. We aimed to (i) systematically review the literature on bariatric surgery in children and adolescents; (ii) meta-analyse change in body mass index (BMI) 1-year post-surgery and (iii) report complications, co-morbidity resolution and health-related quality of life (HRQoL). A systematic literature search (1955–2013) was performed to examine adjustable gastric band, sleeve gastrectomy, Roux-en-Y gastric bypass or biliopancreatic diversions operations among obese children and adolescents. Change in BMI a year after surgery was meta-analysed using a random effects model. In total, 637 patients from 23 studies were included in the meta-analysis. There were significant decreases in BMI at 1 year (average weighted mean BMI difference: −13.5 kg m−2; 95% confidence interval [CI] −14.1 to −11.9). Complications were inconsistently reported. There was some evidence of co-morbidity resolution and improvements in HRQol post-surgery. Bariatric surgery leads to significant short-term weight loss in obese children and adolescents. However, the risks of complications are not well defined in the literature. Long-term, prospectively designed studies, with clear reporting of complications and co-morbidity resolution, alongside measures of HRQol, are needed to firmly establish the harms and benefits of bariatric surgery in children and adolescents.

Risk of completed suicide after bariatric surgery: a systematic review.

Abstract: Bariatric surgery is one of the most effective treatments for morbid obesity, and a large body of research indicates significant long-term weight loss. While overall mortality decreases in patients who received bariatric surgery, a number of studies have shown that suicide rates are higher in bariatric patients than in control groups. The objective of this study was to present a systematic review of suicide mortality after bariatric surgery and calculate an estimate for the suicide rate. Literature researches of the databases PubMed, Web of Knowledge, PsychInfo, ScienceDirect and Google Scholar were conducted. Thirty studies concerning bariatric surgery and completed suicides met the inclusion criteria. We included 28 studies in the estimation of a suicide rate for the bariatric population. Only one study (Tindle et al.) put a main focus on suicide after bariatric surgery; this was therefore chosen as an adequate reference figure for comparison. The other 27 chosen studies were compared with World Health Organization data and the suicide rate reported by Tindle et al. Twenty-three thousand eight hundred eighty-five people were included in the analysis. In the literature, we found a total of 95 suicides when examining 190,000 person-years of post-bariatric surgery data. Little information was provided describing the reasons for suicide and the time-point of these events after surgery. We estimated a suicide rate of 4.1/10,000 person-years (95% confidence interval [3.2, 5.1]/10,000 person-years). A comparison with Tindle et al. demonstrates that their rate is significantly higher than our estimate (P = 0.03). Bariatric surgery patients show higher suicide rates than the general population. Therefore, there is a great need to identify persons at risk and post-operative psychological monitoring is recommended. Language: en

Overweight, obesity and risk of premenopausal breast cancer according to ethnicity: a systematic review and dose-response meta-analysis.

Abstract: Summary The association of overweight and obesity with premenopausal breast cancer remained unclear, ethnicity could play a role. A MEDLINE and PUBMED search of all studies on obesity and premenopausal breast cancer published from 2000 to 2010 was conducted. Dose-response meta-analysis was used to determine the risk of premenopausal breast cancer associated with different anthropometric measurements in different ethnic groups. For body mass index (BMI), each 5 kg m−2 increase was inversely associated with the risk of premenopausal breast cancer (RR = 0.95, 95% confidence interval [CI]: 0.94, 0.97). After stratification by ethnicity, the inverse association remained significant only among Africans (RR = 0.95, 95% CI: 0.91, 0.98) and Caucasians (RR = 0.93, 95% CI: 0.91, 0.95). In contrast, among Asian women, a significant positive association was observed. For waist-to-hip ratio (WHR), each 0.1 unit increase was positively associated with premenopausal breast cancer (RR = 1.08, 95% CI: 1.01, 1.16); the largest effect was detected in Asian women (RR = 1.19, 95% CI: 1.15, 1.24), while small effects of 5% and 6% were observed in African and Caucasian women, respectively. Our results suggest the importance of considering both fat distribution and ethnicity when studying premenopausal breast cancer.

Serum 25-hydroxy vitamin D levels in relation to body mass index: a systematic review and meta-analysis

Abstract: Summary Background Although several cross-sectional studies have investigated serum vitamin D levels in relation to body mass index (BMI), findings are inconsistent. Objective This systematic review and meta-analysis of published cross-sectional data was conducted to summarize the evidence on the link between serum vitamin D levels and BMI in adults. Methods PubMed, ISI Web of Science, Scopus and Google scholar database were searched to May 2012 for all relevant published papers. We found 34 articles that reported the correlation coefficients between serum 25-hydroxy vitamin D (25(OH)D) levels and BMI in apparently healthy adults (>18 years). The primary analysis was done on these 34 papers that reported 37 correlation coefficients. To find the source of between-study heterogeneity, our secondary analysis was confined to eight studies that had used random sampling method and reported the correlations for the whole population. Results Our meta-analysis on 34 relevant papers revealed an overall significant inverse, but weak, association between serum 25(OH)D levels and BMI (Fisher's Z = −0.15, 95% CI: −0.19, −0.11) with a significant heterogeneity between studies. In the subgroup analysis based on gender and study location (East vs. West), the inverse associations were significant in both genders (male: Fisher's Z = −0.11, 95% CI: −0.14, −0.08 and female: −0.14, 95% CI: −0.21, −0.08) and both study locations (East: −0.09, 95% CI: −0.14, −0.04 and West: −0.23, 95% CI: −0.31, −0.17). In the subgroup analysis based on developmental status of countries, the weak inverse association remained significant in developed countries (−0.17, 95% CI: −0.21, −0.14), but not in developing nations (−0.10, 95% CI: −0.20, 0.01). Using meta-regression, we found that latitude (P = 0.91) or longitude (P = 0.2) of cities did not significantly contribute to the computed effect sizes. When we restricted our analysis to eight selected studies that used random sampling method, we reached the same findings. In this analysis, gender and developmental status of countries explained the between-study heterogeneity. Conclusion There is a significant inverse weak correlation between serum 25(OH)D levels and BMI in adult population, except for women living in developing countries. Further research particularly in developing countries and populations living near the equator is needed.

Gender difference of childhood overweight and obesity in predicting the risk of incident asthma: a systematic review and meta-analysis.

Abstract: Summary The aims of our meta-analysis were (i) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; and (ii) to evaluate the gender difference on this relationship. The selection criteria included prospective cohort paediatric studies which use age- and sex-specific body mass index (BMI) as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1,027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non-overweight children (relative risk, 1.19; 95% confidence interval [CI], 1.03–1.37). The relationship was further elevated for obesity vs. non-obesity (relative risk, 2.02; 95% CI, 1.16–3.50). A dose–responsiveness of elevated BMI on asthma incidence was observed (P for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57–3.87; girls: 1.25; 95% CI, 0.51–3.03), with significant dose-dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity–asthma relationship.

Mexico attempts to tackle obesity: the process, results, push backs and future challenges.

Abstract: Mexico's obesity prevalence is one of the world's highest. In 2006, academics, and federal and state government agencies initiated efforts to design a national policy for obesity prevention. The Ministry of Health (MOH) established an expert panel to develop recommendations on beverage intake for a healthy life in 2008. Subsequently, the MOH, with support from academia, initiated the development of the National Agreement for Healthy Nutrition (ANSA). ANSA was signed by all relevant sectoral actors in 2010 and led to initiatives banning sodas and regulating unhealthy food in schools and the design of other yet to be implemented initiatives, such as a front-of-package labeling system. A main challenge of the ANSA has been the lack of harmonization between industry interests and public health objectives and effective accountability and monitoring mechanisms to assess implementation across government sectors. Bold strategies currently under consideration include taxation of sugar-sweetened beverages, improvement of norms for healthy food in schools, regulation of food and beverage marketing to children and implementation of a national front-of-pack labeling system. Strong civil society organizations have embraced the prevention of obesity as their goal and have used evidence from academia to position obesity prevention in the public debate and in the government agenda.

Association of personality with the development and persistence of obesity: a meta-analysis based on individual-participant data.

Abstract: Personality is thought to affect obesity risk but before such information can be incorporated into prevention and intervention plans, robust and converging evidence concerning the most relevant personality traits is needed. We performed a meta-analysis based on individual-participant data from nine cohort studies to examine whether broad-level personality traits predict the development and persistence of obesity (n = 78,931 men and women; mean age 50 years). Personality was assessed using inventories of the Five-Factor Model (extraversion, neuroticism, agreeableness, conscientiousness and openness to experience). High conscientiousness - reflecting high self-control, orderliness and adherence to social norms - was associated with lower obesity risk across studies (pooled odds ratio [OR] = 0.84; 95% confidence interval [CI] = 0.80-0.88 per 1 standard deviation increment in conscientiousness). Over a mean follow-up of 5.4 years, conscientiousness predicted lower obesity risk in initially non-obese individuals (OR = 0.88, 95% CI = 0.85-0.92; n = 33,981) and was associated with greater likelihood of reversion to non-obese among initially obese individuals (OR = 1.08, 95% CI = 1.01-1.14; n = 9,657). Other personality traits were not associated with obesity in the pooled analysis, and there was substantial heterogeneity in the associations between studies. The findings indicate that conscientiousness may be the only broad-level personality trait of the Five-Factor Model that is consistently associated with obesity across populations.

Bioelectrical impedance analysis to estimate body composition in children and adolescents: a systematic review and evidence appraisal of validity, responsiveness, reliability and measurement error.

Abstract: Bioelectrical impedance analysis (BIA) is a practical method to estimate percentage body fat (%BF). In this systematic review, we aimed to assess validity, responsiveness, reliability and measurement error of BIA methods in estimating %BF in children and adolescents.We searched for relevant studies in Pubmed, Embase and Cochrane through November 2012. Two reviewers independently screened titles and abstracts for inclusion, extracted data and rated methodological quality of the included studies. We performed a best evidence synthesis to synthesize the results, thereby excluding studies of poor quality. We included 50 published studies. Mean differences between BIA and reference methods (gold standard [criterion validity] and convergent measures of body composition [convergent validity]) were considerable and ranged from negative to positive values, resulting in conflicting evidence for criterion validity. We found strong evidence for a good reliability, i.e. (intra-class) correlations ≥0.82. However, test-retest mean differences ranged from 7.5% to 13.4% of total %BF in the included study samples, indicating considerable measurement error. Our systematic review suggests that BIA is a practical method to estimate %BF in children and adolescents. However, validity and measurement error are not satisfactory.

Family-based models for childhood-obesity intervention: a systematic review of randomized controlled trials

Abstract: Effective interventions are needed to address the growing epidemic of childhood obesity. In the past 35 years, family-based approach has gradually developed as a preferred intervention. This review aimed to examine the methodological rigour and treatment effectiveness of family-based interventions according to intervention types and theoretical orientations. A total of 15 randomized controlled trials (RCTs) of family-based lifestyle interventions for children and adolescents aged 2-19 years were included. The adapted Methodological Quality Rating Scales (MQRS) and a four-grade qualitative scoring scheme were adopted to evaluate the methodological rigour and the effectiveness of treatment, respectively. The average MQRS score was 7.93 out of 14 points. Ten of the 15 RCTs had well aligned their research questions with appropriate research methods. The overall short-term outcome of the15 RCTs were satisfactory with an average score of 3.1. Family-based interventions rooted in behaviour theory achieved better results than those theoretically connected to family systems theory in terms of treatment effectiveness. Results suggest future studies to improve the methodological design and continue to explore the potential of the family systems approach.

The impact of initiatives to limit the advertising of food and beverage products to children: a systematic review

Abstract: In response to increasing evidence that advertising of foods and beverages affects children's food choices and food intake, several national governments and many of the world's larger food and beverage manufacturers have acted to restrict the marketing of their products to children or to advertise only ‘better for you’ products or ‘healthier dietary choices’ to children Independent assessment of the impact of these pledges has been difficult due to the different criteria being used in regulatory and self-regulatory regimes In this paper, we undertook a systematic review to examine the data available on levels of exposure of children to the advertising of less healthy foods since the introduction of the statutory and voluntary codes The results indicate a sharp division in the evidence, with scientific, peer-reviewed papers showing that high levels of such advertising of less healthy foods continue to be found in several different countries worldwide In contrast, the evidence provided in industry-sponsored reports indicates a remarkably high adherence to voluntary codes We conclude that adherence to voluntary codes may not sufficiently reduce the advertising of foods which undermine healthy diets, or reduce children's exposure to this advertising

Monitoring the price and affordability of foods and diets globally

Abstract: Food prices and food affordability are important determinants of food choices, obesity and non-communicable diseases. As governments around the world consider policies to promote the consumption of healthier foods, data on the relative price and affordability of foods, with a particular focus on the difference between 'less healthy' and 'healthy' foods and diets, are urgently needed. This paper briefly reviews past and current approaches to monitoring food prices, and identifies key issues affecting the development of practical tools and methods for food price data collection, analysis and reporting. A step-wise monitoring framework, including measurement indicators, is proposed. 'Minimal' data collection will assess the differential price of 'healthy' and 'less healthy' foods; 'expanded' monitoring will assess the differential price of 'healthy' and 'less healthy' diets; and the 'optimal' approach will also monitor food affordability, by taking into account household income. The monitoring of the price and affordability of 'healthy' and 'less healthy' foods and diets globally will provide robust data and benchmarks to inform economic and fiscal policy responses. Given the range of methodological, cultural and logistical challenges in this area, it is imperative that all aspects of the proposed monitoring framework are tested rigorously before implementation.