Showing papers in "Obesity Reviews in 2015"

Metabolic syndrome: a closer look at the growing epidemic and its associated pathologies.

Abstract: Summary Obesity is reaching epidemic proportions with recent worldwide figures estimated at 1.4 billion and rising year-on-year. Obesity affects all socioeconomic backgrounds and ethnicities and is a pre-requisite for metabolic syndrome. Metabolic syndrome is a clustering of risk factors, such as central obesity, insulin resistance, dyslipidaemia and hypertension that together culminate in the increased risk of type 2 diabetes mellitus and cardiovascular disease. As these conditions are among the leading causes of deaths worldwide and metabolic syndrome increases the risk of type 2 diabetes mellitus fivefold and cardiovascular disease threefold, it is of critical importance that a precise definition is agreed upon by all interested parties. Also of particular interest is the relationship between metabolic syndrome and cancer. Metabolic syndrome has been associated with a plethora of cancers including breast, pancreatic, colon and liver cancer. Furthermore, each individual risk factor for metabolic syndrome has also an association with cancer. Our review collates internationally generated information on metabolic syndrome, its many definitions and its associations with life-threatening conditions including type 2 diabetes mellitus, cardiovascular disease and cancer, providing a foundation for future advancements on this topic.

Impact of weight bias and stigma on quality of care and outcomes for patients with obesity

Abstract: The objective of this study was to critically review the empirical evidence from all relevant disciplines regarding obesity stigma in order to (i) determine the implications of obesity stigma for healthcare providers and their patients with obesity and (ii) identify strategies to improve care for patients with obesity. We conducted a search of Medline and PsychInfo for all peer-reviewed papers presenting original empirical data relevant to stigma, bias, discrimination, prejudice and medical care. We then performed a narrative review of the existing empirical evidence regarding the impact of obesity stigma and weight bias for healthcare quality and outcomes. Many healthcare providers hold strong negative attitudes and stereotypes about people with obesity. There is considerable evidence that such attitudes influence person-perceptions, judgment, interpersonal behaviour and decision-making. These attitudes may impact the care they provide. Experiences of or expectations for poor treatment may cause stress and avoidance of care, mistrust of doctors and poor adherence among patients with obesity. Stigma can reduce the quality of care for patients with obesity despite the best intentions of healthcare providers to provide high-quality care. There are several potential intervention strategies that may reduce the impact of obesity stigma on quality of care.

Risks associated with obesity in pregnancy, for the mother and baby: a systematic review of reviews

Abstract: Maternal obesity is linked with adverse outcomes for mothers and babies. To get an overview of risks related to obesity in pregnant women, a systematic review of reviews was conducted. For inclusion, reviews had to compare pregnant women of healthy weight with women with obesity, and measure a health outcome for mother and/or baby. Authors conducted full-text screening, quality assurance using the AMSTAR tool and data extraction steps in pairs. Narrative analysis of the 22 reviews included show gestational diabetes, pre-eclampsia, gestational hypertension, depression, instrumental and caesarean birth, and surgical site infection to be more likely to occur in pregnant women with obesity compared with women with a healthy weight. Maternal obesity is also linked to greater risk of preterm birth, large-for-gestational-age babies, foetal defects, congenital anomalies and perinatal death. Furthermore, breastfeeding initiation rates are lower and there is greater risk of early breastfeeding cessation in women with obesity compared with healthy weight women. These adverse outcomes may result in longer duration of hospital stay, with concomitant resource implications. It is crucial to reduce the burden of adverse maternal and foetal/child outcomes caused by maternal obesity. Women with obesity need support to lose weight before they conceive, and to minimize their weight gain in pregnancy.

Obesity and vitamin D deficiency: a systematic review and meta-analysis.

Abstract: Over the past decade, there have been an increasing number of studies on the association between vitamin D deficiency and anthropometric state. However, we did not identify any meta-analyses of the relationship between obesity and vitamin D deficiency in different age groups. Thus, we evaluated the association between obesity and vitamin D deficiency. We searched for observational studies published up to April 2014 in PubMed/Medline, Web of Science and Scopus databases. We performed a meta-analysis in accordance with the random-effects model to obtain the summary measurement (prevalence ratio, PR). Among the 29,882 articles identified, 23 met the inclusion criteria. The prevalence of vitamin D deficiency was 35% higher in obese subjects compared to the eutrophic group (PR: 1.35; 95% CI: 1.21-1.50) and 24% higher than in the overweight group (PR: 1.24; 95% CI: 1.14-1.34). These results indicate that the prevalence of vitamin D deficiency was more elevated in obese subjects. The vitamin D deficiency was associated with obesity irrespective of age, latitude, cut-offs to define vitamin D deficiency and the Human Development Index of the study location.

Longitudinal impact of sleep on overweight and obesity in children and adolescents: a systematic review and bias-adjusted meta-analysis.

Abstract: Short sleep duration is considered a potential risk for overweight/obesity in childhood and adolescence. However, most of the evidence on this topic is obtained from cross-sectional studies; therefore, the nature and extent of the longitudinal associations are unclear. This study explores the prospective association between short sleep and overweight/obesity in young subjects. The MEDLINE, EMBASE, Pubmed, and CINAHL databases were searched for English-language articles, published until May 2014, reporting longitudinal association between sleep and body mass index (BMI) in children and adolescents. Recommendations of the Sleep Health Foundation were used to standardize reference sleep duration. Sleep category, with sleep duration less than the reference sleep, was considered as the short sleep category. Meta-analysis was conducted to explore the association between short sleep and overweight/obesity. A review of 22 longitudinal studies, with subjects from diverse backgrounds, suggested an inverse association between sleep duration and BMI. Meta-analysis of 11 longitudinal studies, comprising 24,821 participants, revealed that subjects sleeping for short duration had twice the risk of being overweight/obese, compared with subjects sleeping for long duration (odds ratio 2.15; 95% confidence interval: 1.64-2.81). This study provides evidence that short sleep duration in young subjects is significantly associated with future overweight/obesity.

What childhood obesity prevention programmes work? A systematic review and meta-analysis

Abstract: Previous reviews of childhood obesity prevention have focused largely on schools and findings have been inconsistent. Funded by the US Agency for Healthcare Research and Quality (AHRQ) and the National Institutes of Health, we systematically evaluated the effectiveness of childhood obesity prevention programmes conducted in high-income countries and implemented in various settings. We searched MEDLINE®, Embase, PsycINFO, CINAHL®, ClinicalTrials.gov and the Cochrane Library from inception through 22 April 2013 for relevant studies, including randomized controlled trials, quasi-experimental studies and natural experiments, targeting diet, physical activity or both, and conducted in children aged 2–18 in high-income countries. Two reviewers independently abstracted the data. The strength of evidence (SOE) supporting interventions was graded for each study setting (e.g. home, school). Meta-analyses were performed on studies judged sufficiently similar and appropriate to pool using random effect models. This paper reported our findings on various adiposity-related outcomes. We identified 147 articles (139 intervention studies) of which 115 studies were primarily school based, although other settings could have been involved. Most were conducted in the United States and within the past decade. SOE was high for physical activity-only interventions delivered in schools with home involvement or combined diet–physical activity interventions delivered in schools with both home and community components. SOE was moderate for school-based interventions targeting either diet or physical activity, combined interventions delivered in schools with home or community components or combined interventions delivered in the community with a school component. SOE was low for combined interventions in childcare or home settings. Evidence was insufficient for other interventions. In conclusion, at least moderately strong evidence supports the effectiveness of school-based interventions for preventing childhood obesity. More research is needed to evaluate programmes in other settings or of other design types, especially environmental, policy and consumer health informatics-oriented interventions.

The effects of high-intensity interval training on glucose regulation and insulin resistance: a meta-analysis.

Abstract: The aim of this meta-analysis was to quantify the effects of high-intensity interval training (HIIT) on markers of glucose regulation and insulin resistance compared with control conditions (CON) or continuous training (CT). Databases were searched for HIIT interventions based upon the inclusion criteria: training ≥2 weeks, adult participants and outcome measurements that included insulin resistance, fasting glucose, HbA1c or fasting insulin. Dual interventions and participants with type 1 diabetes were excluded. Fifty studies were included. There was a reduction in insulin resistance following HIIT compared with both CON and CT (HIIT vs. CON: standardized mean difference [SMD] = -0.49, confidence intervals [CIs] -0.87 to -0.12, P = 0.009; CT: SMD = -0.35, -0.68 to -0.02, P = 0.036). Compared with CON, HbA1c decreased by 0.19% (-0.36 to -0.03, P = 0.021) and body weight decreased by 1.3 kg (-1.9 to -0.7, P < 0.001). There were no statistically significant differences between groups in other outcomes overall. However, participants at risk of or with type 2 diabetes experienced reductions in fasting glucose (-0.92 mmol L(-1), -1.22 to -0.62, P < 0.001) compared with CON. HIIT appears effective at improving metabolic health, particularly in those at risk of or with type 2 diabetes. Larger randomized controlled trials of longer duration than those included in this meta-analysis are required to confirm these results.

eHealth interventions for the prevention and treatment of overweight and obesity in adults: a systematic review with meta-analysis.

Abstract: Summary A systematic review of randomized controlled trials was conducted to evaluate the effectiveness of eHealth interventions for the prevention and treatment of overweight and obesity in adults. Eight databases were searched for studies published in English from 1995 to 17 September 2014. Eighty-four studies were included, with 183 intervention arms, of which 76% (n = 139) included an eHealth component. Sixty-one studies had the primary aim of weight loss, 10 weight loss maintenance, eight weight gain prevention, and five weight loss and maintenance. eHealth interventions were predominantly delivered using the Internet, but also email, text messages, monitoring devices, mobile applications, computer programs, podcasts and personal digital assistants. Forty percent (n = 55) of interventions used more than one type of technology, and 43.2% (n = 60) were delivered solely using eHealth technologies. Meta-analyses demonstrated significantly greater weight loss (kg) in eHealth weight loss interventions compared with control (MD −2.70 [−3.33,−2.08], P < 0.001) or minimal interventions (MD −1.40 [−1.98,−0.82], P < 0.001), and in eHealth weight loss interventions with extra components or technologies (MD 1.46 [0.80, 2.13], P < 0.001) compared with standard eHealth programmes. The findings support the use of eHealth interventions as a treatment option for obesity, but there is insufficient evidence for the effectiveness of eHealth interventions for weight loss maintenance or weight gain prevention.

Testosterone and obesity.

Abstract: Testosterone is a key hormone in the pathology of metabolic diseases such as obesity. Low testosterone levels are associated with increased fat mass (particularly central adiposity) and reduced lean mass in males. These morphological features are linked to metabolic dysfunction, and testosterone deficiency is associated with energy imbalance, impaired glucose control, reduced insulin sensitivity and dyslipidaemia. A bidirectional relationship between testosterone and obesity underpins this association indicated by the hypogonadal–obesity cycle and evidence weight loss can lead to increased testosterone levels. Androgenic effects on enzymatic pathways of fatty acid metabolism, glucose control and energy utilization are apparent and often tissue specific with differential effects noted in different regional fat depots, muscle and liver to potentially explain the mechanisms of testosterone action. Testosterone replacement therapy demonstrates beneficial effects on measures of obesity that are partially explained by both direct metabolic actions on adipose and muscle and also potentially by increasing motivation, vigour and energy allowing obese individuals to engage in more active lifestyles. The degree of these beneficial effects may be dependent on the treatment modality with longer term administration often achieving greater improvements. Testosterone replacement may therefore potentially be an effective adjunctive treatment for weight management in obese men with concomitant hypogonadism.

Appetite control and energy balance: impact of exercise

Abstract: Exercise is widely regarded as one of the most valuable components of behaviour that can influence body weight and therefore help in the prevention and management of obesity. Indeed, long-term controlled trials show a clear dose-related effect of exercise on body weight. However, there is a suspicion, particularly fuelled by media reports, that exercise serves to increase hunger and drive up food intake thereby nullifying the energy expended through activity. Not everyone performing regular exercise will lose weight and several investigations have demonstrated a huge individual variability in the response to exercise regimes. What accounts for this heterogeneous response? First, exercise (or physical activity) through the expenditure of energy will influence the energy balance equation with the potential to generate an energy deficit. However, energy expenditure also influences the control of appetite (i.e. the physiological and psychological regulatory processes underpinning feeding) and energy intake. This dynamic interaction means that the prediction of a resultant shift in energy balance, and therefore weight change, will be complicated. In changing energy intake, exercise will impact on the biological mechanisms controlling appetite. It is becoming recognized that the major influences on the expression of appetite arise from fat-free mass and fat mass, resting metabolic rate, gastric adjustment to ingested food, changes in episodic peptides including insulin, ghrelin, cholecystokinin, glucagon-like peptide-1 and tyrosine-tyrosine, as well as tonic peptides such as leptin. Moreover, there is evidence that exercise will influence all of these components that, in turn, will influence the drive to eat through the modulation of hunger (a conscious sensation reflecting a mental urge to eat) and adjustments in postprandial satiety via an interaction with food composition. The specific actions of exercise on each physiological component will vary in strength from person to person (according to individual physiological characteristics) and with the intensity and duration of exercise. Therefore, individual responses to exercise will be highly variable and difficult to predict.

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

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

Personality traits and obesity: a systematic review.

Abstract: Based on a bio-social-ecological systems model of the development and maintenance of obesity, there has been in the last few years a growing research interest in the association of obesity and personality traits. The aim of the present review was a comprehensive and critical evaluation of the existing literature taking into account the methodological quality of studies to enhance our understanding of personality traits associated with body weight, the development of overweight and obesity as well as the effectiveness of weight loss interventions including bariatric surgery. Personality traits play an important role both as risk as well as protective factors in the development of overweight and obesity. While thus in particular 'neuroticism', 'impulsivity' and 'sensitivity to reward' appear as risk factors, 'conscientiousness' and 'self-control' have been shown to have a protective function in relation to weight gain. Conscientiousness is a measure of regulation of internal urges and self-discipline, and may thus provide a potential source of control over impulsive reward-oriented behaviour. The results of the present review suggest that, within the context of therapeutic weight reduction measures, it is meaningful to identify subgroups of patients for whom specific treatment options need to be developed, such as measures for strengthening self-control skills.

Impact of policy and built environment changes on obesity-related outcomes: a systematic review of naturally occurring experiments.

Abstract: Policies and changes to the built environment are promising targets for obesity prevention efforts and can be evaluated as 'natural'- or 'quasi'-experiments. This systematic review examined the use of natural- or quasi-experiments to evaluate the efficacy of policy and built environment changes on obesity-related outcomes (body mass index, diet or physical activity). PubMed (Medline) was searched for studies published 2005-2013; 1,175 abstracts and 115 papers were reviewed. Of the 37 studies included, 18 studies evaluated impacts on nutrition/diet, 17 on physical activity and 3 on body mass index. Nutrition-related studies found greater effects because of bans/restrictions on unhealthy foods, mandates offering healthier foods, and altering purchase/payment rules on foods purchased using low-income food vouchers compared with other interventions (menu labelling, new supermarkets). Physical activity-related studies generally found stronger impacts when the intervention involved improvements to active transportation infrastructure, longer follow-up time or measured process outcomes (e.g., cycling rather than total physical activity), compared with other studies. Only three studies directly assessed body mass index or weight, and only one (installing light-rail system) observed a significant effect. Studies varied widely in the strength of their design and studies with weaker designs were more likely to report associations in the positive direction.

Association between caesarean section and childhood obesity: a systematic review and meta-analysis

Abstract: Birth by caesarean section has been recently implicated in the aetiology of childhood obesity, but studies examining the association have varied with regard to their settings, designs, and adjustment for potential confounders. We conducted a systematic review and meta-analysis to summarize the available evidence and to explore study characteristics as sources of heterogeneity. A search of Medline, EMBASE, and Web of Science identified 28 studies. Random effects meta-analysis was used to calculate pooled risk ratios (RR) with 95% confidence intervals (CI). Caesarean section had a RR of 1.34 (CI 1.18-1.51) for obesity in the child compared with vaginal birth. The RR was lower for studies that adjusted for maternal pre-pregnancy weight than for studies that did not (1.29, CI 1.16-1.44 vs. 1.55, CI 1.11-2.17). Studies that examined multiple early life factors reported lower RRs than studies that specifically examined caesarean section (1.39, CI 1.23-1.57 vs. 1.23, CI 0.97-1.56). Effect estimates did not vary by child's age at obesity assessment, study design or country income. Children born by caesarean section are at higher risk of developing obesity in childhood. Findings are limited by a moderate heterogeneity among studies and the potential for residual confounding and publication bias.

Macrophage recruitment in obese adipose tissue

Abstract: Obesity is characterized as a chronic state of low-grade inflammation with progressive immune cell infiltration into adipose tissues. Adipose tissue macrophages play critical roles in the establishment of the chronic inflammatory state and metabolic dysfunctions. The novel discovery that pro-inflammatory macrophages are recruited to obese adipose tissue prompted an increased interest in the interplay between immune cells and metabolism. Since this discovery, many works have been published investigating the factors that lead to macrophage recruitment, the phenotypic change of adipose tissue macrophages, and metabolic dysfunctions. Adipokines and chemokines are key mediators that play crucial roles in crosstalk between adipocytes and macrophages and in regulating the adipose tissue inflammation. In the present review, we discuss the obesity-mediated adipose tissue remodelling, and particularly, the role of adipokines/chemokines in macrophage recruitment to obese adipose tissue. This review provides new insights into the physiological role of these factors and identifies a potential therapeutic target for obesity and associated disorders.

Integrating movement in academic classrooms: understanding, applying and advancing the knowledge base.

Abstract: In the context of comprehensive and coordinated approaches to school health, academic classrooms have gained attention as a promising setting for increasing physical activity and reducing sedentary time among children. The aims of this paper are to review the rationale and knowledge base related to movement integration in academic classrooms, consider the practical applications of current knowledge to interventions and teacher education, and suggest directions for future research. Specifically, this paper (i) situates movement integration amid policy and research related to children's health and the school as a health-promoting environment; (ii) highlights the benefits of movement integration; (iii) summarizes movement integration programs and interventions; (iv) examines factors associated with classroom teachers' movement integration; (v) offers strategies for translating research to practice and (vi) forwards recommendations for future inquiry related to the effectiveness and sustainability of efforts to integrate movement into classroom routines. This paper provides a comprehensive resource for developing state-of-the-art initiatives to maximize children's movement in academic classrooms as a key strategy for important goals in both education and public health.

Influence of food companies' brand mascots and entertainment companies' cartoon media characters on children's diet and health: a systematic review and research needs.

Abstract: Reducing the extent and persuasive power of marketing unhealthy foods to children worldwide are important obesity prevention goals. Research is limited to understand how brand mascots and cartoon media characters influence children's diet. We conducted a systematic review of five electronic databases (2000-2014) to identify experimental studies that measured how food companies' mascots and entertainment companies' media characters influence up to 12 diet-related cognitive, behavioural and health outcomes for children under 12 years. Eleven studies met the inclusion criteria. Studies used 21 unique popular media characters, but no brand mascots. Results suggest that cartoon media character branding can positively increase children's fruit or vegetable intake compared with no character branding. However, familiar media character branding is a more powerful influence on children's food preferences, choices and intake, especially for energy-dense and nutrient-poor foods (e.g. cookies, candy or chocolate) compared with fruits or vegetables. Future research should use a theoretically grounded conceptual model and larger and more diverse samples across settings to produce stronger findings for mediating and moderating factors. Future research can be used to inform the deliberations of policymakers, practitioners and advocates regarding how media character marketing should be used to support healthy food environments for children.

A proposed approach to systematically identify and monitor the corporate political activity of the food industry with respect to public health using publicly available information

Abstract: Unhealthy diets represent one of the major risk factors for non-communicable diseases. There is currently a risk that the political influence of the food industry results in public health policies that do not adequately balance public and commercial interests. This paper aims to develop a framework for categorizing the corporate political activity of the food industry with respect to public health and proposes an approach to systematically identify and monitor it. The proposed framework includes six strategies used by the food industry to influence public health policies and outcomes: information and messaging; financial incentive; constituency building; legal; policy substitution; opposition fragmentation and destabilization. The corporate political activity of the food industry could be identified and monitored through publicly available data sourced from the industry itself, governments, the media and other sources. Steps for country-level monitoring include identification of key food industry actors and related sources of information, followed by systematic data collection and analysis of relevant documents, using the proposed framework as a basis for classification of results. The proposed monitoring approach should be pilot tested in different countries as part of efforts to increase the transparency and accountability of the food industry. This approach has the potential to help redress any imbalance of interests and thereby contribute to the prevention and control of non-communicable diseases.

A meta-analysis of active video games on health outcomes among children and adolescents.

Abstract: This meta-analysis synthesizes current literature concerning the effects of active video games (AVGs) on children/adolescents' health-related outcomes. A total of 512 published studies on AVGs were located, and 35 articles were included based on the following criteria: (i) data-based research articles published in English between 1985 and 2015; (ii) studied some types of AVGs and related outcomes among children/adolescents and (iii) had at least one comparison within each study. Data were extracted to conduct comparisons for outcome measures in three separate categories: AVGs and sedentary behaviours, AVGs and laboratory-based exercise, and AVGs and field-based physical activity. Effect size for each entry was calculated with the Comprehensive Meta-Analysis software in 2015. Mean effect size (Hedge's g) and standard deviation were calculated for each comparison. Compared with sedentary behaviours, AVGs had a large effect on health outcomes. The effect sizes for physiological outcomes were marginal when comparing AVGs with laboratory-based exercises. The comparison between AVGs and field-based physical activity had null to moderate effect sizes. AVGs could yield equivalent health benefits to children/adolescents as laboratory-based exercise or field-based physical activity. Therefore, AVGs can be a good alternative for sedentary behaviour and addition to traditional physical activity and sports in children/adolescents.

Dieting and weight cycling as risk factors for cardiometabolic diseases: who is really at risk?

Abstract: Despite the poor prognosis of dieting in obesity management, which often results in repeated attempts at weight loss and hence weight cycling, the prevalence of dieting has increased continuously in the past decades in parallel to the steadily increasing prevalence of obesity. However, dieting and weight cycling are not limited to those who are obese or overweight as substantial proportions of the various population groups with normal body weight also attempt to lose weight. These include young and older adults as well as children and adolescents who perceive themselves as too fat (due to media, parental and social pressures), athletes in weight-sensitive competitive sports (i.e. mandatory weight categories, gravitational and aesthetic sports) or among performers for whom a slim image is professionally an advantage. Of particular concern is the emergence of evidence that some of the potentially negative health consequences of repeated dieting and weight cycling are more readily seen in people of normal body weight rather than in those who are overweight or obese. In particular, several metabolic and cardiovascular risk factors associated with weight cycling in normal-weight individuals have been identified from cross-sectional and prospective studies as well as from studies of experimentally induced weight cycling. In addition, findings from studies of experimental weight cycling have reinforced the notion that fluctuations of cardiovascular risk variables (such as blood pressure, heart rate, sympathetic activity, blood glucose, lipids and insulin) with probable repeated overshoots above normal values during periods of weight regain put an additional stress on the cardiovascular system. As the prevalence of diet-induced weight cycling is increasing due to the opposing forces of an 'obesigenic' environment and the media pressure for a slim figure (that even targets children), dieting and weight cycling is likely to become an increasingly serious public health issue.

Determinants of sugar-sweetened beverage consumption in young children: a systematic review

Abstract: Sugar-sweetened beverage (SSB) consumption is associated with adverse health outcomes. Improved understanding of the determinants will inform effective interventions to reduce SSB consumption. A total of 46,876 papers were identified through searching eight electronic databases. Evidence from intervention (n = 13), prospective (n = 6) and cross-sectional (n = 25) studies on correlates/determinants of SSB consumption was quality assessed and synthesized. Twelve correlates/determinants were associated with higher SSB consumption (child's preference for SSBs, TV viewing/screen time and snack consumption; parents' lower socioeconomic status, lower age, SSB consumption, formula milk feeding, early introduction of solids, using food as rewards, parental-perceived barriers, attending out-of-home care and living near a fast food/convenience store). Five correlates/determinants were associated with lower SSB consumption (parental positive modelling, parents' married/co-habiting, school nutrition policy, staff skills and supermarket nearby). There was equivocal evidence for child's age and knowledge, parental knowledge, skills, rules/restrictions and home SSB availability. Eight intervention studies targeted multi-level (child, parents, childcare/preschool setting) determinants; four were effective. Four intervention studies targeted parental determinants; two were effective. One (effective) intervention targeted the preschool environment. There is consistent evidence to support potentially modifiable correlates/determinants of SSB consumption in young children acting at parental (modelling), child (TV viewing) and environmental (school policy) levels.

Leptin resistance in diet-induced obesity: the role of hypothalamic inflammation.

Abstract: The consumption of Western diets, high in sugar and saturated fat, is a crucial contributor to the alarming incidence of obesity and its associated morbidities. These diets have been reported to induce an inflammatory response in the hypothalamus, which promotes the development of central leptin resistance and obesity. This inflammatory signalling involves dynamic changes in the expression and activity of several mediators of the innate immune system, including toll-like receptor 4, IκB kinase-β/nuclear factor-κB, c-Jun N-terminal kinase, suppressor of cytokine signalling 3 and pro-inflammatory cytokines, as well as the induction of endoplasmic reticulum stress and autophagy defect. Although the exact cellular mechanisms remain incompletely understood, recent evidence suggests that the inflammatory response is at least mediated by interactions between neurons and non-neuronal cells such as microglia and astrocytes. Current evidence of the contribution of each inflammatory mediator to leptin resistance and diet-induced obesity (DIO), including their reciprocal interactions and cell-type-specific effects, is reviewed and integrated in a conceptual model. Based upon this model and pharmacological intervention studies, several inflammatory mediators are proposed to be promising therapeutic targets for the treatment of DIO.

Effectiveness of weight loss interventions--is there a difference between men and women: a systematic review.

Abstract: Effective strategies are required to reduce the prevalence of overweight and obesity; however, the effectiveness of current weight loss programmes is variable. One contributing factor may be the difference in weight loss success between men and women. A systematic review was conducted to determine whether the effectiveness of weight loss interventions differs between men and women. Randomized controlled trials published up until March 2014 were included. Effect sizes (Hedges' g) were used to examine the difference in weight outcomes between men and women. A total of 58 studies met the eligibility criteria with 49 studies of higher quality included in the final data synthesis. Eleven studies that directly compared weight loss in men and women reported a significant sex difference. Ten of these reported that men lost more weight than women; however, women also lost a significant amount of weight. Analysis of effect sizes found small differences in weight loss favouring men for both diet (g = 0.489) and diet plus exercise (g = 0.240) interventions. There is little evidence from this review to indicate that men and women should adopt different weight loss strategies. Current evidence supports moderate energy restriction in combination with exercise for weight loss in both men and women.

Obesity and iron deficiency: a quantitative meta-analysis.

Abstract: Summary Hypoferraemia (i.e. iron deficiency) was initially reported among obese individuals several decades ago; however, whether obesity and iron deficiency are correlated remains unclear. Here, we evaluated the putative association between obesity and iron deficiency by assessing the concentration of haematological iron markers and the risks associated with iron deficiency in both obese (including overweight) subjects and non-overweight participants. We performed a systematic search in the databases PubMed and Embase for relevant research articles published through December 2014. A total of 26 cross-sectional and case–control studies were analysed, comprising 13,393 overweight/obese individuals and 26,621 non-overweight participants. Weighted or standardized mean differences of blood iron markers and odds ratio (OR) of iron deficiency were compared between the overweight/obese participants and the non-overweight participants using a random-effects model. Compared with the non-overweight participants, the overweight/obese participants had lower serum iron concentrations (weighted mean difference [WMD]: −8.37 μg dL−1; 95% confidence interval [CI]: −11.38 to −5.36 μg dL−1) and lower transferrin saturation percentages (WMD: 2.34%, 95% CI: −3.29% to −1.40%). Consistent with this finding, the overweight/obese participants had a significantly increased risk of iron deficiency (OR: 1.31; 95% CI: 1.01–1.68). Moreover, subgroup analyses revealed that the method used to diagnose iron deficiency can have a critical effect on the results of the association test; specifically, we found a significant correlation between iron deficiency and obesity in studies without a ferritin-based diagnosis, but not in studies that used a ferritin-based diagnosis. Based upon these findings, we concluded that obesity is significantly associated with iron deficiency, and we recommend early monitoring and treatment of iron deficiency in overweight and obese individuals. Future longitudinal studies will help to test whether causal relationship exists between obesity and iron deficiency.

Adiposity and risk of thyroid cancer: a systematic review and meta‐analysis

Abstract: Summary Thyroid cancer incidence has increased rapidly over time, as has obesity prevalence. A link between the two appears plausible, but the relation of adiposity to thyroid cancer remains incompletely understood. We performed a meta-analysis of adiposity measures and thyroid cancer using studies identified through October 2014. Twenty-one articles yielded data on 12,199 thyroid cancer cases. We found a statistically significant 25% greater risk of thyroid cancer in overweight individuals and a 55% greater thyroid cancer risk in obese individuals as compared with their normal-weight peers. Each 5-unit increase in body mass index (BMI), 5 kg increase in weight, 5 cm increase in waist or hip circumference and 0.1-unit increase in waist-to-hip ratio were associated with 30%, 5%, 5% and 14% greater risks of thyroid cancer, respectively. When evaluated by histologic type, obesity was significantly positively related to papillary, follicular and anaplastic thyroid cancers, whereas it revealed an inverse association with medullary thyroid cancer. Both general and abdominal adiposity are positively associated with thyroid cancer. However, relations with BMI vary importantly by tumour histologic type.

The role for adipose tissue in weight regain after weight loss.

Abstract: Weight regain after weight loss is a substantial challenge in obesity therapeutics. Dieting leads to significant adaptations in the homeostatic system that controls body weight, which promotes overeating and the relapse to obesity. In this review, we focus specifically on the adaptations in white adipose tissues that contribute to the biological drive to regain weight after weight loss. Weight loss leads to a reduction in size of adipocytes and this decline in size alters their metabolic and inflammatory characteristics in a manner that facilitates the clearance and storage of ingested energy. We present the hypothesis whereby the long-term signals reflecting stored energy and short-term signals reflecting nutrient availability are derived from the cellularity characteristics of adipose tissues. These signals are received and integrated in the hypothalamus and hindbrain and an energy gap between appetite and metabolic requirements emerges and promotes a positive energy imbalance and weight regain. In this paradigm, the cellularity and metabolic characteristics of adipose tissues after energy-restricted weight loss could explain the persistence of a biological drive to regain weight during both weight maintenance and the dynamic period of weight regain.

Maternal body mass index and risk of birth and maternal health outcomes in low‐ and middle‐income countries: a systematic review and meta‐analysis

Abstract: We conducted a systematic review and meta-analysis of population-based cohort studies of maternal body mass index (BMI) and risk of adverse birth and health outcomes in low- and middle-income countries. PubMed, Embase, CINAHL and the British Nursing Index were searched from inception to February 2014. Forty-two studies were included. Our study found that maternal underweight was significantly associated with higher risk of preterm birth (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.01-1.27), low birthweight (OR, 1.66; 95% CI, 1.50-1.84) and small for gestational age (OR, 1.85; 95% CI, 1.69-2.02). Compared with mothers with normal BMI, overweight or obese mothers were at increased odds of gestational diabetes, pregnancy-induced hypertension, pre-eclampsia, caesarean delivery and post-partum haemorrhage. The population-attributable risk (PAR) indicated that if women were entirely unexposed to overweight or obesity during the pre-pregnancy or early pregnancy period, 14% to 35% fewer women would develop gestational diabetes, pre-eclampsia or pregnancy-induced hypertension in Brazil, China, India, Iran or Thailand. The highest PAR of low birthweight attributable to maternal underweight was found in Iran (20%), followed by India (18%), Thailand (10%) and China (8%). Treatment and prevention of maternal underweight, overweight or obesity may help reduce the burden on maternal and child health in developing countries.

Attentional biases for food cues in overweight and individuals with obesity: a systematic review of the literature.

Abstract: Summary Obesity rates have increased dramatically in recent decades, and it has proven difficult to treat. An attentional bias towards food cues may be implicated in the aetiology of obesity and influence cravings and food consumption. This review systematically investigated whether attentional biases to food cues exist in overweight/obese compared with healthy weight individuals. Electronic database were searched for relevant papers from inception to October 2014. Only studies reporting food-related attentional bias between either overweight (body mass index [BMI] 25.0–29.9 kg m−2) or obese (BMI ≥ 30) participants and healthy weight participants (BMI 18.5–24.9) were included. The findings of 19 studies were reported in this review. Results of the literature are suggestive of differences in attentional bias, with all but four studies supporting the notion of enhanced reactivity to food stimuli in overweight individuals and individuals with obesity. This support for attentional bias was observed primarily in studies that employed psychophysiological techniques (i.e. electroencephalogram, eye-tracking and functional magnetic resonance imaging). Despite the heterogeneous methodology within the featured studies, all measures of attentional bias demonstrated altered cue-reactivity in individuals with obesity. Considering the theorized implications of attentional biases on obesity pathology, researchers are encouraged to replicate flagship studies to strengthen these inferences.

Inverse relationship between body mass index and mortality in older nursing home residents : a meta-analysis of 19,538 elderly subjects

Abstract: Body mass index (BMI) and mortality in old adults from the general population have been related in a U-shaped or J-shaped curve. However, limited information is available for elderly nursing home p ...

The impact of bariatric surgery on quality of life: a systematic review and meta-analysis

Abstract: This study aims to review the obesity literature in order to assess the impact of bariatric surgery on quality of life and the between-study variation by examining the standardized mean magnitude of effect in change in the levels of quality of life. The following databases EMBASE, PubMed, PsycINFO, CINAHL, the Cochrane Library and Web of Science were systematically searched for studies examining change in quality of life in adults receiving bariatric surgery for obesity. Seventy-two studies were included with a total of 9,433 participants treated for obesity with bariatric surgery. The average impact of bariatric surgery on quality of life corresponded to an effect size of 0.88 (95% CI: 0.80-0.96), indicating that bariatric surgery has a significant positive influence on quality of life in general. The impact varied considerably across studies with bariatric surgery showing a significantly greater positive influence on physical quality of life compared to mental quality of life. Bariatric surgery is effective in improving quality of life, especially when looking at physical well-being. Greater focus on the psychological well-being of the person undergoing surgery for obesity may lead to a better post-surgery prognosis for more people.