Prospective study of intentional weight loss and mortality in overweight white men aged 40-64 years

On the estimation of the effect of weight change on a health outcome using observational data, by utilising the target trial emulation framework

BACKGROUND/OBJECTIVES

When studying the effect of weight change between two time points on a health outcome using observational data, two main problems arise initially (i) 'when is time zero?' and (ii) 'which confounders should we account for?' From the baseline date or the 1st follow-up (when the weight change can be measured)? Different methods have been previously used in the literature that carry different sources of bias and hence produce different results.

METHODS

We utilised the target trial emulation framework and considered weight change as a hypothetical intervention. First, we used a simplified example from a hypothetical randomised trial where no modelling is required. Then we simulated data from an observational study where modelling is needed. We demonstrate the problems of each of these methods and suggest a strategy.

INTERVENTIONS

weight loss/gain vs maintenance.

RESULTS

The recommended method defines time-zero at enrolment, but adjustment for confounders (or exclusion of individuals based on levels of confounders) should be performed both at enrolment and the 1st follow-up.

CONCLUSIONS

The implementation of our suggested method [adjusting for (or excluding based on) confounders measured both at baseline and the 1st follow-up] can help researchers attenuate bias by avoiding some common pitfalls. Other methods that have been widely used in the past to estimate the effect of weight change on a health outcome are more biased. However, two issues remain (i) the exposure is not well-defined as there are different ways of changing weight (however we tried to reduce this problem by excluding individuals who develop a chronic disease); and (ii) immortal time bias, which may be small if the time to first follow up is short.

Association of change in fat and lean mass with incident cardiovascular events for women in midlife and beyond: A prospective study using dual-energy x-ray absorptiometry (DXA)

OBJECTIVE

To determine whether changes in fat and lean mass over time, quantified using dual-energy x-ray absorptiometry (DXA), are related to incident cardiovascular events. Previous studies using surrogate anthropometric methods have had inconsistent findings.

STUDY DESIGN

Prospective, longitudinal observational study of women aged 40 to 80 randomly selected from the electoral roll and stratified into decades: 40-49, 50-59, 60-69 and 70-79 years.

MAIN OUTCOME MEASURES

Changes in anthropometric measurements (body mass index and waist-to-hip ratio) and DXA-quantified fat mass and lean mass between the first and fifth years of the study. Incident cardiovascular events recorded from the sixth to the 12th year.

RESULTS

In total 449 participants (87.9 %) were analyzed. A 10 % or greater decrease in total fat mass index was associated with a 67 % lower likelihood of any cardiovascular event (OR = 0.33, 95%CI 0.15-0.71); no association was observed for an increase. A 10 % or greater decrease in abdominal fat mass index was associated with a 62 % lower likelihood of incident stroke (OR = 0.38, 95%CI 0.16-0.91); no association was observed for an increase. A 10 % or greater decrease in appendicular lean mass index resulted in increased odds ratio of 2.91 for incident peripheral artery events (OR = 2.91, 95%CI 1.18-7.20).

CONCLUSIONS

Reducing fat mass for women in midlife and beyond may decrease the risk of cardiovascular events. An increase in fat mass may not contribute to additional cardiovascular events. A reduction in limb muscle mass may provide an independent marker for cardiometabolic risk and peripheral artery disease. No independent association was found using anthropometric measurements and incident cardiovascular events.

Weight loss and all-cause mortality: A propensity score matching cohort study

BACKGROUND

Weight loss was supposed to help with decreasing risk of premature mortality. However, results on this topic remain debatable and limited by study design.

OBJECTIVE

The present study aimed to investigate the association between weight loss and all-cause mortality among US adults with overweight or obesity in a national cohort study by using propensity score matching (PSM) analysis.

METHODS

A total of 5486 pairs of participants were matched in the National Health and Nutrition Examination Survey (NHANES, 2003-2015) after PSM. Hazard ratios (95% confidence intervals) (HRs (95% CIs)) were employed to evaluate the association between weight loss indicated by long-term weight loss (LTWL) and all-cause mortality by using Cox proportional hazards regression models.

RESULTS

During a median follow-up of 6.8 years, 674 participants died from all-cause mortality. In each PSM match, compared with participants with LTWL < 5%, the HRs (95% CIs) for participants with LTWL of 5-9.9% (2877 pairs), 10-14.9% (1315 pairs), and ≥ 15% (1294 pairs) were 1.18 (0.83-1.68) (P = 0.366), 1.65 (1.17-2.34) (P = 0.005), and 1.91 (1.21-3.00) (P = 0.006), respectively. The significant increased risk of all-cause mortality for LTWL ≥ 15% remained among male, female, participants aged ≥ 65 years, without weight loss intention, with non-communicable diseases, and without exceeding estimated energy requirement.

CONCLUSION

Weight loss especially for being ≥ 15% should be cautious for US adults with overweight or obesity.

Association between bariatric surgery and risks of cancer among Chinese patients with type 2 diabetes mellitus: A retrospective cohort study

BACKGROUND

To examine risks of cancers, obesity-related cancers (eg, cancers in digestive organs, breast, ovary, kidney, thyroid, and myeloma), cancer-related mortality, and all-cause mortality in patients with type 2 diabetes mellitus (T2DM) and obesity who underwent bariatric surgery.

METHODS

A retrospective cohort of 1944 T2DM patients with obesity (345 bariatric surgery patients and 1599 matched controls) who were free of cancer from 2006 to 2017 was assembled. One-to-five propensity score matching followed by propensity score trimming was used to balance baseline covariates.

RESULTS

During a mean follow-up period of 37 months, there are risks that in 3.2%, 1.4%, 0.9%, and 3.2% of bariatric patients cancer, obesity-related cancer, cancer-related mortality, and all-cause mortality, respectively, would occur. Surgical patients were found to have reduced incidence rates (IRs) of obesity-related cancer (0.531/100 person-years, 95% confidence interval [CI]: 0.172-1.238/100 person-years) and cancer of breast and genital organs (0.394/100 person-years, 95% CI: 0.048-1.424/100 person-years) than matched control patients whose IRs for obesity-related cancer and cancer of breast and genital organs were 0.627/100 person-years (95% CI: 0.426-0.889/100 person-years) and 0.521/100 person-years (95% CI: 0.277-0.891/100 person-years), respectively. Patients in the surgical group had a significant reduction in risk of all-cause mortality (hazard ratio [HR] = 0.508, P = .041). Effects of bariatric surgery on any cancers (HR = 1.254, P = .510), obesity-related cancers (HR = 0.843, P = .724), and cancer mortality (HR = 1.304, P = .694) were not significant.

CONCLUSIONS

Bariatric surgery was not associated with risks of overall cancer, obesity-related cancer, and cancer mortality among T2DM patients with obesity at 3 years.

Associations of weight changes with all-cause, cancer and cardiovascular mortality: A prospective cohort study

Objectives

Previous studies suggest that changes in body weight can lead to an increased risk of mortality in the general population, although the results are controversial. The current study sought to investigate this association further using data from the UK Biobank.

Study design

This is a large prospective population-based cohort study. Data were derived from the UK Biobank, with the initial assessments commencing between 2006 and 2010.

Methods

Proportional hazard models were used to assess the association between self-reported weight change and risk of all-cause, cancer and cardiovascular mortality. The effect of gender was also investigated.

Results

Of 433,829 participants with data for self-reported weight change, the mean age was 56 (standard deviation [SD]: 8.1) years and 55% were female. In total, 55% of participants reported no weight change, 28% gained weight, 15% lost weight, 2% did not know and 0.1% preferred not to give an answer. The median follow-up was 7.1 (interquartile range [IQR]: 6.4–7.8) years. Compared with participants with no weight change, those with weight loss had an increased risk of all-cause mortality (adjusted hazard ratio [HR] 1.25, 95% confident interval [CI] 1.18–1.32), cancer death (HR 1.17, 95% CI 1.08–1.27) and cardiovascular death (HR 1.26, 95% CI 1.12–1.43). Similarly, participants reporting weight gain also had an increased risk of all-cause mortality (HR 1.08, 95% CI 1.02–1.13), cancer death (HR 1.14, 95% CI 1.07–1.22) and cardiovascular death (HR 1.27, 95% CI 1.14–1.42). Participants who had a response ‘do not know’ or ‘prefer not to answer’ showed an increased risk of all-cause and cardiovascular mortality, particularly in men.

Conclusions

The results of this study highlight the importance of maintaining a stable weight in middle-aged adults. Further studies are needed to understand the pathophysiology of weight change and its effects on mortality.

Metabolic Surgery and Cancer Risk: An Opportunity for Mechanistic Research

Simple Summary

Metabolic (bariatric) surgery (MBS) provides the greatest maximum and sustained weight loss among individuals who are morbidly obese. It is more effective than lifestyle interventions in improving or eliminating type 2 diabetes mellitus (T2DM) and in decreasing cardiovascular (CV) risk. Preclinical studies have been conducted to investigate the mechanisms by which MBS leads to the benefits in T2DM and CV risk. In this review, we describe the emerging evidence that MBS may also impact cancer risk and mortality, and whom may benefit most. We describe the long term involvement and commitment of the National Institutes of Health in obesity research in general and MBS in particular. We outline the need for additional research to understand the mechanism(s) by which MBS may influence cancer, since these mechanism(s) are currently unknown.

Abstract

Metabolic (bariatric) surgery (MBS) is recommended for individuals with a BMI > 40 kg/m² or those with a BMI 35–40 kg/m² who have one or more obesity related comorbidities. MBS leads to greater initial and sustained weight loss than nonsurgical weight loss approaches. MBS provides dramatic improvement in metabolic function, associated with a reduction in type 2 diabetes mellitus and cardiovascular risk. While the number of MBS procedures performed in the U.S. and worldwide continues to increase, they are still only performed on one percent of the affected population. MBS also appears to reduce the risk of certain obesity related cancers, although which cancers are favorably impacted vary by study, who benefits most is uncertain, and the mechanism(s) driving this risk reduction are mostly speculative. The goal of this manuscript is to highlight (1) emerging evidence that MBS influences cancer risk, and that the potential benefit appears to vary based on cancer, gender, surgical procedure, and likely other variables; (2) the role of the NIH in MBS research in T2DM and CV risk for many years, and more recently in cancer; and (3) the opportunity for research to understand the mechanism(s) by which MBS influences cancer. There is evidence that women benefit more from MBS than men, that MBS may actually increase the risk of colorectal cancer in both women and men, and there is speculation that the benefit in cancer risk reduction may vary according to which MBS procedure an individual undergoes. Herein, we review what is currently known, the historical role of government, especially the National Institutes of Health (NIH), in driving this research, and provide suggestions that we believe could lead to a better understanding of whether and how MBS impacts cancer risk, which cancers are impacted either favorably or unfavorably, the role of the NIH and other research agencies, and key questions to address that will help us to move the science forward.

Incidence of cardiovascular disease and mortality in underweight individuals

BACKGROUND

Few studies have evaluated the association between being underweight and having cardiovascular disease in the general population. We investigated the incidence of stroke, myocardial infarction (MI), and all-cause mortality according to detailed underweight categories in a large population cohort.

METHODS

We included 4 164 364 individuals who underwent a health examination that was conducted as part of the Korean National Health Insurance Service between January 2009 and December 2012 and followed them up to determine the incidence of stroke, MI, and all-cause mortality until 31 December 2016. Based on the body mass index, the study population was categorized into normal (18.50-22.99), mild (17.00-18.49), moderate (16.00-16.99), and severe underweight (<16.00) groups. Cox proportional hazards analyses were performed to calculate the hazard ratio for stroke, MI, and mortality according to the severity of underweight in reference to the normal weight. We adjusted for age, sex, lifestyle, economic status, co-morbidity, blood pressure, glucose, lipid level, and waist circumference.

RESULTS

The mean age of the 4 164 364 eligible subjects in this study cohort was 44.4 ± 14.3 years, and 46.1% of the participants were male; 46 728 strokes, 30 074 MIs, and 121 080 deaths occurred during 27 449 902 person-years. The incidence of stroke, MI, and all-cause mortality increased proportionally with the severity of underweight in the multivariate model. This proportional association became more evident when the waist circumference was additionally adjusted. The respective hazard ratios (95% confidence intervals) for mild, moderate, and severe underweight were 1.10 (1.06-1.15), 1.11 (1.02-1.20), and 1.38 (1.24-1.53) for stroke; 1.19 (1.14-1.25), 1.40 (1.27-1.53), and 1.86 (1.64-2.11) for MI; and 1.63 (1.60-1.67), 2.10 (2.02-2.17), and 2.98 (2.85-3.11) for all-cause mortality. In stratified analyses based on waist circumference, the severity of underweight was consistently associated with a higher risk of stroke, MI, and death.

CONCLUSIONS

The severity of underweight was associated with a higher risk of stroke, MI, and all-cause mortality.

Intentional weight loss as a predictor of type 2 diabetes occurrence in a general adult population

INTRODUCTION

Observational and intervention studies have verified that weight loss predicts a reduced type 2 diabetes (T2D) risk. At the population level, knowledge on the prediction of self-report intentional weight loss (IWL) on T2D incidence is, however, sparse. We studied the prediction of self-report IWL on T2D incidence during a 15-year follow-up in a general adult population.

RESEARCH DESIGN AND METHODS

The study sample from the representative Finnish Health 2000 Survey comprised 4270 individuals, aged 30-69 years. IWL was determined with questions concerning dieting attempts and weight loss during the year prior to baseline. Incident T2D cases during a 15-year follow-up were drawn from national health registers. The strength of the association between IWL and T2D incidence was estimated with the Cox model.

RESULTS

During the follow-up, 417 incident cases of T2D occurred. IWL predicted an increased risk of T2D incidence (HR 1.44; 95% CI 1.11 to 1.87, p=0.008) in a multivariable model. In interaction analyses comparing individuals with and without IWL, a suggestively elevated risk emerged in men, the younger age group, among less-educated people and in individuals with unfavorable values in several lifestyle factors.

CONCLUSIONS

Self-report IWL may predict an increased risk of T2D in long-term, probably due to self-implemented IWL tending to fail. The initial prevention of weight gain and support for weight maintenance after weight loss deserve greater emphasis in order to prevent T2D.

Weight-centric pharmacological management of type 2 diabetes mellitus - An essential component of cardiovascular disease prevention

Obesity and overweight are contributing factors for diseases such as type 2 diabetes mellitus (T2DM), hypertension, hyperlipidemia, and ultimately, cardiovascular (CV) disease. Obesity is imposing an increasing health burden in rich and poor nations, with almost 30% of people globally now either obese or overweight - a staggering 2.1 billion. The link between obesity and T2DM is widely held to involve two adverse effects: obesity-induced insulin resistance and β-cell failure. This "unified field theory" raises questions about whether defects favoring progressive weight gain and metabolic impairment also contribute to β-cell decompensation. The concept of weight-centric management of T2DM is considered justified because of the strong negative impact of obesity on the effects of treatment of diabetes. Two pharmacotherapy options are considered: drugs developed primarily for blood glucose control that also exert a favorable effect on body weight and drugs developed primarily to induce weight loss that also have a favorable effect on glycemia. Treating hunger counter-regulatory mechanisms will have an additional effect on glucose control in T2DM. This narrative review addresses advances in pharmacotherapy for the management of obesity and obesity-related co-morbidities, with a focus on T2DM. It is also important to identify the correct balance between weight-centric and glucose-centric management of T2DM.

Mitogen-Activated Protein Kinase (MAPK) and Obesity-Related Cancer

Obesity is a major public health concern worldwide. The increased risk of certain types of cancer is now an established deleterious consequence of obesity, although the molecular mechanisms of this are not completely understood. In this review, we aim to explore the links between MAPK signalling and obesity-related cancer. We focus mostly on p38 and JNK MAPK, as the role of ERK remains unclear. These links are seen through the implication of MAPK in obesity-related immune paralysis as well as through effects on the endoplasmic reticulum stress response and activation of aromatase. By way of example, we highlight areas of interest and possibilities for future research in endometrioid endometrial cancer and hepatocellular carcinoma associated with non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH) and MAPK.

The Risks of Cardiovascular Disease and Mortality Following Weight Change in Adults with Diabetes: Results from ADVANCE

CONTEXT

Weight loss is strongly recommended for overweight and obese adults with type 2 diabetes. Unintentional weight loss is associated with increased risk of all-cause mortality, but few studies have examined its association with cardiovascular outcomes in patients with diabetes.

OBJECTIVE

To evaluate 2-year weight change and subsequent risk of cardiovascular events and mortality in established type 2 diabetes.

DESIGN AND SETTING

The Action in Diabetes and Vascular Disease: Preterax and Diamicron-MR Controlled Evaluation was an international, multisite 2×2 factorial trial of intensive glucose control and blood pressure control. We examined 5 categories of 2-year weight change: >10% loss, 4% to 10% loss, stable (±<4%), 4% to 10% gain, and >10% gain. We used Cox regression with follow-up time starting at 2 years, adjusting for intervention arm, demographics, cardiovascular risk factors, and diabetes medication use from the 2-year visit.

RESULTS

Among 10 081 participants with valid weight measurements, average age was 66 years. By the 2-year examination, 4.3% had >10% weight loss, 18.4% had 4% to 10% weight loss, and 5.3% had >10% weight gain. Over the following 3 years of the trial, >10% weight loss was strongly associated with major macrovascular events (hazard ratio [HR], 1.75; 95% confidence interval [CI], 1.26-2.44), cardiovascular mortality (HR, 2.76; 95% CI, 1.87-4.09), all-cause mortality (HR, 2.79; 95% CI, 2.10-3.71), but not major microvascular events (HR, 0.91; 95% CI, 0.61-1.36), compared with stable weight. There was no evidence of effect modification by baseline body mass index, age, or type of diabetes medication.

CONCLUSIONS

In the absence of substantial lifestyle changes, weight loss may be a warning sign of poor health meriting further workup in patients with type 2 diabetes.

Changes in Cardiovascular Disease Risk Factors with Unintentional Versus Intentional Weight Loss: The Coronary Artery Risk Development in Young Adults Study

BACKGROUND

It is well known that total and intentional weight loss (IWL) are associated with reductions in cardiovascular disease (CVD) risk factors, however, associations with unintentional weight loss (UWL) have not been studied.

METHODS

We examined annual changes in blood pressure and lipids associated with UWL versus IWL in 576 participants from the Coronary Artery Risk Development in Young Adults (CARDIA) study who had lost weight over one of two time intervals (i.e., study years 5-7 or 7-10) and reported whether the weight loss was intentional at the end of the interval.

RESULTS

After adjusting for age, sex, race, and field center, an annual weight loss smaller than 6% resulted in small improvements in lipids that were similar regardless of intentionality. When annual weight loss was ≥6%, UWL was associated with less reduction in total cholesterol (-0.2 vs. -10.4 mg/dL), low-density lipoprotein cholesterol (-3.2 vs. -9.4 mg/dL), and triglycerides (-0.5 vs. -19.0 mg/dL) compared with IWL. Intentionality was not associated with the size of changes in blood pressure (systolic blood pressure: -2.7 vs. -2.0 mmHg; diastolic blood pressure: -2.2 vs. -1.3 mmHg) and high-density lipoprotein cholesterol (3.2 vs. 2.7 mg/dL).

CONCLUSIONS

Substantial UWL may be accompanied or preceded by other biological changes in this young adult population that alter changes in CVD risk factors that are associated with IWL.

Global patterns in excess body weight and the associated cancer burden

The prevalence of excess body weight and the associated cancer burden have been rising over the past several decades globally. Between 1975 and 2016, the prevalence of excess body weight in adults-defined as a body mass index (BMI) ≥ 25 kg/m² -increased from nearly 21% in men and 24% in women to approximately 40% in both sexes. Notably, the prevalence of obesity (BMI ≥ 30 kg/m² ) quadrupled in men, from 3% to 12%, and more than doubled in women, from 7% to 16%. This change, combined with population growth, resulted in a more than 6-fold increase in the number of obese adults, from 100 to 671 million. The largest absolute increase in obesity occurred among men and boys in high-income Western countries and among women and girls in Central Asia, the Middle East, and North Africa. The simultaneous rise in excess body weight in almost all countries is thought to be driven largely by changes in the global food system, which promotes energy-dense, nutrient-poor foods, alongside reduced opportunities for physical activity. In 2012, excess body weight accounted for approximately 3.9% of all cancers (544,300 cases) with proportion varying from less than 1% in low-income countries to 7% or 8% in some high-income Western countries and in Middle Eastern and Northern African countries. The attributable burden by sex was higher for women (368,500 cases) than for men (175,800 cases). Given the pandemic proportion of excess body weight in high-income countries and the increasing prevalence in low- and middle-income countries, the global cancer burden attributable to this condition is likely to increase in the future. There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living. The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight.

Observational Evidence for Unintentional Weight Loss in All-Cause Mortality and Major Cardiovascular Events: A Systematic Review and Meta-Analysis

The obesity paradox has been described in several observational cohorts and meta-analysis. However, evidence of the intentionality of weight loss in all-cause deaths and major cardiovascular events (MACE) in prospective cohorts is unclear. We analysed whether involuntary weight loss is associated with increased cardiovascular events and mortality. In a systematic review, we searched multiple electronic databases for observational studies published up to October 2016. Studies reporting risk estimates for unintentional weight loss compared with stable weight in MACE and mortality were included. Fifteen studies met the selection criteria, with a total of 178,644 participants. For unintentional weight loss, we found adjusted risk ratios (RRs) with confidence intervals (CIs) of 1.38 (95% CI: 1.23, 1.53) and 1.17 (95% CI: 0.98, 1.37) for all-cause mortality and MACE, respectively. Participants with comorbidities, overweight and obese populations, and older adults yielded RRs (95% CI) of 1.49 (1.30, 1.68), 1.11 (1.04, 1.18), and 1.81 (1.59, 2.03), respectively. Unintentional weight loss had a significant impact on all-cause mortality. We found no protective effect of being overweight or obese for unintentional weight loss and MACE.

Behavioral and Pharmacotherapy Weight Loss Interventions to Prevent Obesity-Related Morbidity and Mortality in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Overweight and obesity have been associated with adverse health effects.

OBJECTIVE

To systematically review evidence on benefits and harms of behavioral and pharmacotherapy weight loss and weight loss maintenance interventions in adults to inform the US Preventive Services Task Force.

DATA SOURCES

MEDLINE, PubMed Publisher-Supplied Records, PsycINFO, and the Cochrane Central Register of Controlled Trials for studies published through June 6, 2017; ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials through August 2017; and ongoing surveillance in targeted publications through March 23, 2018. Studies from previous reviews were reevaluated for inclusion.

STUDY SELECTION

Randomized clinical trials (RCTs) focusing on weight loss or weight loss maintenance in adults.

DATA EXTRACTION AND SYNTHESIS

Data were abstracted by one reviewer and confirmed by another. Random-effects meta-analyses were conducted for weight loss outcomes in behavior-based interventions.

MAIN OUTCOMES AND MEASURES

Health outcomes, weight loss or weight loss maintenance, reduction in obesity-related conditions, and adverse events.

RESULTS

A total of 122 RCTs (N = 62 533) and 2 observational studies (N = 209 993) were identified. Compared with controls, participants in behavior-based interventions had greater mean weight loss at 12 to 18 months (-2.39 kg [95% CI, -2.86 to -1.93]; 67 studies [n = 22065]) and less weight regain (-1.59 kg [95% CI, -2.38 to -0.79]; 8 studies [n = 1408]). Studies of medication-based weight loss and maintenance interventions also reported greater weight loss or less weight regain in intervention compared with placebo groups at 12 to 18 months (range, -0.6 to -5.8 kg; no meta-analysis). Participants with prediabetes in weight loss interventions had a lower risk of developing diabetes compared with controls (relative risk, 0.67 [95% CI, 0.51 to 0.89]). There was no evidence of other benefits, but most health outcomes such as mortality, cardiovascular disease, and cancer were infrequently reported. Small improvements in quality of life in some medication trials were noted but were of unclear clinical significance. There was no evidence of harm such as cardiovascular disease from behavior-based interventions; higher rates of adverse events were associated with higher dropout rates in medication groups than in placebo groups.

CONCLUSIONS AND RELEVANCE

Behavior-based weight loss interventions with or without weight loss medications were associated with more weight loss and a lower risk of developing diabetes than control conditions. Weight loss medications, but not behavior-based interventions, were associated with higher rates of harms. Long-term weight and health outcomes data, as well as data on important subgroups, were limited.

Surgical treatment of obesity

Obesity prevalence continues to increase worldwide, as do the numerous chronic diseases associated with obesity, including diabetes, non-alcoholic fatty liver disease, dyslipidemia, and hypertension. The prevalence of bariatric surgery also continues to increase and remains the most effective and sustainable treatment for obesity. Over the last several years, numerous prospective and longitudinal studies have demonstrated the benefits of bariatric surgery on weight loss, mortality, and other chronic diseases. Even though the mechanisms underlying many of these beneficial effects remain poorly understood, surgical management of obesity continues to increase given its unmatched efficacy. In this commentary, we discuss recent clinical advancements as well as several areas needed for future research, including indications for bariatric and metabolic surgery, determination of responders and non-responders, metabolic surgery in non-obese individuals, and the evolving role of bariatric surgery in adolescents.

Russian national clinical recommendations for morbid obesity treatment in adults. 3rd revision (Morbid obesity treatment in adults)

The presented paper is a third revision of the clinical recommendations for the treatment of morbid obesity in adults. Morbid obesity is a condition with body mass index (BMI) 40 kg / m2 or a BMI 35 kg / m2 in the presence of serious complications associated with obesity. The recommendations provide data on the prevalence of obesity, its etiology and pathogenesis, as well as on associated complications. The necessary methods for laboratory and instrumental diagnosis of obesity are described in detail. In this revision of the recommendations, the staging of prescribing conservative and surgical methods for the treatment of obesity are determined. For the first time, a group of patients with obesity and type 2 diabetes mellitus is selected, in whom metabolic surgery allows a long-term improvement in the control of glycemia or remission of diabetes mellitus.

Obesity as an Avoidable Cause of Cancer (Attributable Risks)

Excess body weight, commonly categorised as overweight (body mass index, BMI 25.0-29.9 kg/m2) and obesity (BMI ≥30 kg/m2) is an established risk factor for increased incidence of several adult cancers. As body weight is modifiable, there is a potential for cancer prevention. Calculation of attributable risk (here expressed at population attributable fraction, PAF) offers an estimate of the burden of excess cancers attributable to elevated BMI in populations, and thus an approximation of avoidable cases and the opportunity for prevention. Using counterfactual methods, the estimated PAF worldwide attributed to elevated BMI is 3.6 % or nearly half a million new cancer cases in adults (aged 30 years and older after a 10-year lag period). PAFs are higher in women compared with men (5.4 % vs. 1.9 %). Endometrial, post-menopausal breast, and colon cancers account for nearly two-thirds of cancers attributable to elevated BMI. Globally, excess body weight is the third commonest attributable risk factor for cancer (after smoking and infection); in western populations such as the UK, excess weight ranks as second commonest risk factor.

Weight Loss and Coronary Heart Disease: Sensitivity Analysis for Unmeasured Confounding by Undiagnosed Disease

BACKGROUND

Evidence for the effect of weight loss on coronary heart disease (CHD) or mortality has been mixed. The effect estimates can be confounded due to undiagnosed diseases that may affect weight loss.

METHODS

We used data from the Nurses' Health Study to estimate the 26-year risk of CHD under several hypothetical weight loss strategies. We applied the parametric g-formula and implemented a novel sensitivity analysis for unmeasured confounding due to undiagnosed disease by imposing a lag time for the effect of weight loss on chronic disease. Several sensitivity analyses were conducted.

RESULTS

The estimated 26-year risk of CHD did not change under weight loss strategies using lag times from 0 to 18 years. For a 6-year lag time, the risk ratios of CHD for weight loss compared with no weight loss ranged from 1.00 (0.99, 1.02) to 1.02 (0.99, 1.05) for different degrees of weight loss with and without restricting the weight loss strategy to participants with no major chronic disease. Similarly, no protective effect of weight loss was estimated for mortality risk. In contrast, we estimated a protective effect of weight loss on risk of type 2 diabetes.

CONCLUSION

We estimated that maintaining or losing weight after becoming overweight or obese does not reduce the risk of CHD or death in this cohort of middle-age US women. Unmeasured confounding, measurement error, and model misspecification are possible explanations but these did not prevent us from estimating a beneficial effect of weight loss on diabetes.

Association between Weight Change and Mortality in Community Living Older People Followed for Up to 14 Years. The Hordaland Health Study (HUSK)

OBJECTIVES

To study the importance of weight change with regard to mortality in older people.

DESIGN

Prospective cohort study.

PARTICIPANTS

The cohort includes participants in the Hordaland Health Study, Norway, 1997-99 (N=2935, age 71-74 years) who had previously participated in a survey in 1992-93.

MEASUREMENTS

Participants with weight measured at both surveys were followed for mortality through 2012. Cox proportional hazards models were used to calculate risk of death according to changes in weight. Hazard ratios (HR) with 95% confidence intervals (CIs) for people with stable weight (± <5% weight change) were compared to people who lost (≥5%) or gained (≥5%) weight. Cox regression with penalized spline was used to evaluate the association between weight change (in kg) and mortality. Analyses were adjusted for age, sex, physical activity, smoking, diabetes, hypertension, and previous myocardial infarction or stroke. Participants with cancer were excluded.

RESULTS

Compared to those with stable weight, participants who lost ≥5% weight had an increased mortality risk (HR 1.59 [95% CI: 1.35-1.89]) while the group with weight gain ≥5% did not (HR 1.07 [95% CI 0.90-1.28]). Penalized spline identified those who lost more than about three kg or gained more than about 12 kg as having increased risk of death.

CONCLUSION

Even a minor weight loss of ≥5% or >3 kg were significantly associated with increased risk of mortality. Thus, weight should be routinely measured in older adults.

Bariatric Surgery: Pathophysiology and Outcomes

Diabetes mellitus and obesity are closely interrelated and pose a major burden on health care in terms of morbidity and mortality. Weight loss has favorable metabolic benefits for glycemic control and improvement of metabolic syndrome. Bariatric surgery (BS) is the most effective treatment for weight loss with durable results as compared to lifestyle modification. BS procedures have been associated with significant reduction in abdominal obesity, metabolic syndrome components, and glycemic control requiring fewer medications. Long-term risks of surgery include nutritional deficiencies, osteoporosis, bone fractures, and hyperinsulinemic hypoglycemia, which need to be carefully balanced with metabolic benefits for individual patients.

Diabetes Diagnosis and Weight Loss in Middle-Aged Adults

Using three waves of Health and Retirement Study data, this study investigated whether (a) self-reported physician-diagnosed diabetes prior to 1994 predicted weight loss between 1994 and 1996 in adults who were aged 51 to 61 and relatively healthy but overweight in 1992 (n = 2,642) and (b) socioeconomic status influenced that relationship. The authors found that these overweight middle-aged adults were at least 50% more likely to report that they lost at least 10 pounds of excess body weight if they had been diagnosed with diabetes than if they had not. Furthermore, the authors found that neither education nor net worth predicted weight loss in these adults. Identifying the social, psychological, and physiological mechanisms linking chronic conditions and health behaviors can inform policy makers and health care providers and enhance the development of effective interventions to prevent or reduce health risks in middle-aged and older adults.

Aging, Obesity, and Mortality: Misplaced Concern About Obese Older People?

Although there is widespread agreement that obesity (body mass index [BMI] ≥ 30 kg/m(2)) raises health risks, debate has ensued on whether obese older adults are also at greater risk. This study examines the effect of obesity on mortality for younger and older adults to determine whether the risk of obesity is lessened in later life. Data from a 20-year follow-up of a national sample of adults were used to examine the risk of obesity on mortality (N = 6,767). Cox models reveal that obesity raises mortality risk for adults of all ages, but this relationship is nearly twice as strong for persons younger than 50 years of age. Being slightly overweight in later life is associated with lower mortality risk, but obesity raises mortality risk, especially for ischemic heart disease. Obesity in middle age is a grave public health concern, but obesity in later life also merits attention.

Cost-Effectiveness of Sibutramine in the Treatment of Obesity

Background. This study reports incremental cost-utility of sibutramine compared to diet and lifestyle advice for the treatment of obesity. Method. The model estimates the costs and quality of life benefits associated with weight loss itself and the reduced incidence of coronary heart disease (CHD) and diabetes in the “healthy obese.” The key source of effectiveness data is 2 randomized controlled trials over 12 months. Utility gain per kilogram lost is analyzed using Short Form–36 data from sibutramine trials. The impact on CHD is estimated using the Framingham risk equation, which relates age/sex/body mass index to risk of heart disease. The reduced incidence of diabetes due to weight loss is estimated from published literature. A life tables approach was used to calculate the cost per quality-adjusted life year (QALY) of 1 year’s treatment with sibutramine compared to diet and lifestyle advice. Results. The incremental cost per QALY of sibutramine is £4780. Sensitivity analyses show that this result is sensitive to utility associated with weight loss and the frequency of monitoring.Conclusions. Sibutramine is a costeffective treatment for obesity when combined with diet and lifestyle advice.

Outcomes of Laparoscopic Sleeve Gastrectomy and Roux-en-Y Gastric Bypass in Patients Older than 60

BACKGROUND

The proportion of population older than 60 years is rapidly increasing. The majority of this older population suffers from multiple comorbid conditions including obesity. Non-surgical means of weight loss do not offer a predictable solution. Surgical interventions seem to be the most promising solution for the obesity problem, but there is a relative lack of data in literature regarding bariatric procedures in older populations.

OBJECTIVES

Our study aims to evaluate the safety and efficacy of bariatric surgery in patients older than 60 years of age, to determine the weight loss, rate of operation-related complications, and impacts of surgery on comorbid conditions, and to compare the effectiveness of bariatric surgery in older patients to the effectiveness of bariatric surgery for the general population at Montefiore Medical Center.

METHODS

A retrospective review of patients' medical records were used to collect data to create databases to identify patients older than 60 years age who underwent bariatric surgery procedures spanning a 4-year period between January 2009 and October 2013. Data reviewed included age, sex, height, pre-operative weight, and body mass index (BMI), presence of obesity-related comorbid conditions, procedures performed, mortality, immediate or delayed complications, length of follow-up, excess weight lost, BMI points lost, percent of excess weight loss (%EWL), hemoglobin Alc (HgbA1c), and effects on obesity-related comorbid conditions. The percent of excess weight loss and number of complications within the older patient group were compared to the general population, which consists of patients between the ages of 22 and 59.

RESULTS

Ninety-eight patients were identified. Seven patients did not follow up at any time period, and the eight patients who had laparoscopic adjustable gastric band (LAGB) were also excluded due to insufficient data. Overall, 83 patients who were above the age of 60 were examined; 30 patients had laparoscopic sleeve gastrectomy (LSG), and 53 patients underwent laparoscopic Roux-en-Y gastric bypass (LRYGB). The average patient age was 63.4 years, the average pre-operative weight was 122.3 kg, and the average excess body weight was 54.8 kg. The pre-existing comorbid conditions included 90.4 % hypertension (HTN), 63.9 % diabetes mellitus (DM), 50.6 % hyperlipidemia (HL), 34.9 % obstructive sleep apnea (OSA), and 30.1 % asthma. The average %EWL at 3 months, 6 months, and 12 months was 37.0, 51.3, and 65.2 %, respectively. A significant proportion of patients reported resolution or improvement in comorbid conditions. When results were compared to the general, population there was no significant difference in the number of complications that occurred within each of the two groups. The difference in %EWL at the 12-month follow-up was not statistically significant between the general population and the older patients, which suggests that both groups lost a similar amount of weight and that bariatric surgery on patients who are above the age of 60 is effective.

CONCLUSIONS

Bariatric surgery can be safe and effective for patients older than 60 years of age with a low morbidity and mortality; the weight loss and improvement in comorbidities in older patients were clinically significant. When compared to the general population, there was no statistically significant difference in the average %EWL at 12 months or the number of complications due to surgery. Long-term effects of such interventions will need further studies and investigations.

'Adipaging': ageing and obesity share biological hallmarks related to a dysfunctional adipose tissue

The increasing ageing of our societies is accompanied by a pandemic of obesity and related cardiometabolic disorders. Progressive dysfunction of the white adipose tissue is increasingly recognized as an important hallmark of the ageing process, which in turn contributes to metabolic alterations, multi-organ damage and a systemic pro-inflammatory state ('inflammageing'). On the other hand, obesity, the paradigm of adipose tissue dysfunction, shares numerous biological similarities with the normal ageing process such as chronic inflammation and multi-system alterations. Accordingly, understanding the interplay between accelerated ageing related to obesity and adipose tissue dysfunction is critical to gain insight into the ageing process in general as well as into the pathophysiology of obesity and other related conditions. Here we postulate the concept of 'adipaging' to illustrate the common links between ageing and obesity and the fact that, to a great extent, obese adults are prematurely aged individuals.

Intentional Weight Loss and Longevity in Overweight Patients with Type 2 Diabetes: A Population-Based Cohort Study

Objective

This study examined the influence of weight loss on long-term morbidity and mortality in overweight (BMI≥25kg/m²) patients with type 2 diabetes, and tested the hypothesis that therapeutic intentional weight loss supervised by a medical doctor prolongs life and reduces the risk for cardiovascular disease in these patients.

Methods

This is a 19 year cohort study of patients in the intervention arm of the randomized clinical trial Diabetes Care in General Practice. Weight and prospective intentions for weight loss were monitored every third month for six years in 761 consecutive patients (≥40 years) newly diagnosed with diabetes in general practices throughout Denmark in 1989–92. Multivariable Cox regression was used to estimate the association between weight change during the monitoring period (year 0 to 6) and the outcomes during the succeeding 13 years (year 6 to 19) in 444 patients who were overweight at diagnosis and alive at the end of the monitoring period (year 6). The analysis was adjusted for age, sex, education, BMI at diagnosis, change in smoking, change in physical activity, change in medication, and the Charlson comorbidity 6-year score. Outcomes were from national registers.

Results

Overall, weight loss regardless of intention was an independent risk factor for increased all-cause mortality (P<0.01). The adjusted hazard ratio for all-cause mortality, cardiovascular mortality, and cardiovascular morbidity attributable to an intentional weight loss of 1 kg/year was 1.20 (95%CI 0.97–1.50, P = 0.10), 1.26 (0.93–1.72, P = 0.14), and 1.06 (0.79–1.42, P = 0.71), respectively. Limiting the analysis to include only those patients who survived the first 2 years after the monitoring period did not substantially change these estimates. A non-linear spline estimate indicated a V-like association between weight change and all-cause mortality, suggesting the best prognosis for those who maintained their weight.

Conclusions

In this population-based cohort of overweight patients with type 2 diabetes, successful therapeutic intentional weight loss, supervised by a doctor over six years, was not associated with reduced all-cause mortality or cardiovascular morbidity/mortality during the succeeding 13 years.

Obesity and Diabetes: The Increased Risk of Cancer and Cancer-Related Mortality

Obesity and type 2 diabetes are becoming increasingly prevalent worldwide, and both are associated with an increased incidence and mortality from many cancers. The metabolic abnormalities associated with type 2 diabetes develop many years before the onset of diabetes and, therefore, may be contributing to cancer risk before individuals are aware that they are at risk. Multiple factors potentially contribute to the progression of cancer in obesity and type 2 diabetes, including hyperinsulinemia and insulin-like growth factor I, hyperglycemia, dyslipidemia, adipokines and cytokines, and the gut microbiome. These metabolic changes may contribute directly or indirectly to cancer progression. Intentional weight loss may protect against cancer development, and therapies for diabetes may prove to be effective adjuvant agents in reducing cancer progression. In this review we discuss the current epidemiology, basic science, and clinical data that link obesity, diabetes, and cancer and how treating obesity and type 2 diabetes could also reduce cancer risk and improve outcomes.

Consequences of obesity and weight loss: a devil's advocate position

Obesity is associated with multiple negative health consequences and current weight management guidelines recommend all obese persons to lose weight. However, recent evidence suggests that not all obese persons are negatively affected by their weight and that weight loss does not necessarily always improve health. The purpose of this review is not to trivialize the significant health risks associated with obesity, but to discuss subpopulations of obese people who are not adversely affected, or may even benefit from higher adiposity, and in who weight loss per se may not always be the most appropriate recommendation. More specifically, this review will take a devil's advocate position when discussing the consequences of obesity and weight loss for adults with established cardiovascular disease and type 2 diabetes, weight cyclers, metabolically healthy obese adults, youth, older adults and obese individuals who are highly fit.

The prognostic importance of weight loss in coronary artery disease: a systematic review and meta-analysis

OBJECTIVE

To assess the prognostic impact of weight loss on clinical outcomes in patients with coronary artery disease (CAD).

METHODS

We performed a systematic review and meta-analysis of the prognostic effects of weight loss in patients with CAD on a composite outcome of all-cause mortality, cardiovascular mortality, and major adverse cardiac events considering studies published between January 1, 1964, and August 8, 2013. We considered weight loss "intentional" when it occurred in the presence of programmed therapeutic lifestyle changes and "observational" when no such intervention was specified.

RESULTS

We searched 1218 abstracts, of which 12 studies with 14 cohorts met the inclusion criteria. A total of 35,335 patients (mean age, 64 years; 72% male; body mass index [BMI], 30; 3.2 years of follow-up) were included. Overall, weight loss was associated with a greater risk of the composite outcome (relative risk [RR], 1.30; 95% CI, 1.00-1.69; P=.05). However, heterogeneity was high (I(2)=90%) and was substantially explained by weight loss intentionality. Presumed intentional weight loss (4 cohorts) was associated with improved outcomes (RR, 0.67; 95% CI, 0.56-0.80; P<.001), whereas observational weight loss (10 cohorts) was associated with worsened outcomes (RR, 1.62; 95% CI, 1.26-2.08; P<.001; interaction P<.001).

CONCLUSION

Whereas observational weight loss is associated with increased adverse cardiovascular events, intentional weight loss is associated with lower clinical events. These results suggest that the underlying mechanism of weight loss (ie, intentional or unintentional) affects its impact on subsequent risk in persons with known CAD.

Involuntary weight loss

Involuntary weight loss remains an important and challenging clinical problem, with a high degree of morbidity and mortality. Because of the frequency of finding a serious underlying diagnosis, clinicians must be thorough in assessment, keeping in mind a broad range of possible causes. Although prediction scores exist, they have not been broadly validated; therefore, clinical judgment remains ever essential.

Body mass and weight change in adults in relation to mortality risk

Using data from the National Institutes of Health-AARP Diet and Health Study, we evaluated the influence of adulthood weight history on mortality risk. The National Institutes of Health-AARP Diet and Health Study is an observational cohort study of US men and women who were aged 50-71 years at entry in 1995-1996. This analysis focused on 109,947 subjects who had never smoked and were younger than age 70 years. We estimated hazard ratios of total and cause-specific mortality for recalled body mass index (BMI; weight (kg)/height (m)(2)) at ages 18, 35, and 50 years; weight change across 3 adult age intervals; and the effect of first attaining an elevated BMI at 4 successive ages. During 12.5 years' follow-up through 2009, 12,017 deaths occurred. BMI at all ages was positively related to mortality. Weight gain was positively related to mortality, with stronger associations for gain between ages 18 and 35 years and ages 35 and 50 years than between ages 50 and 69 years. Mortality risks were higher in persons who attained or exceeded a BMI of 25.0 at a younger age than in persons who reached that threshold later in adulthood, and risks were lowest in persons who maintained a BMI below 25.0. Heavier initial BMI and weight gain in early to middle adulthood strongly predicted mortality risk in persons aged 50-69 years.

Obesity and weight management in the elderly: a focus on men

The rising rate of overweight/obesity among the ever-growing ageing population is imposing massive and rapidly changing burdens of ill health. The observation that the BMI value associated with the lowest relative mortality is slightly higher in older than in younger adults, mainly through its reduced impact on coronary heart disease, has often been misinterpreted that obesity is not as harmful in the elderly, who suffer a large range of disabling consequences of obesity. All medical consequences of obesity are multi-factorial and most alleviated by modest, achievable weight loss (5-10 kg) with an evidence-based maintenance strategy. But severe obesity, e.g. BMI >40 may demand greater weight loss e.g. >15 kg to reverse type 2 diabetes. Since relatively reduced physical activity and reduced muscle mass (sarcopenic obesity) are common in the elderly, combining exercise and modest calorie restriction optimally reduces fat mass and preserves muscle mass - age presents no obstacle and reducing polypharmacy is a valuable outcome. The currently licensed drug orlistat has no age-related hazards and is effective in a low fat diet, but the risks from bariatric surgery begin to outweigh benefits above age 60. For the growing numbers of obese elderly with diabetes, the glucagon-like peptide-1 (GLP-1) receptor analogue liraglutide appears a safe way to promote and maintain substantial weight loss. Obesity and sarcopenia should be prevented from younger age and during life-transitions including retiral to improve future health outcomes and quality of life, with a focus on those in "obese families".

Review of the key results from the Swedish Obese Subjects (SOS) trial - a prospective controlled intervention study of bariatric surgery

Obesity is a risk factor for diabetes, cardiovascular disease events, cancer and overall mortality. Weight loss may protect against these conditions, but robust evidence for this has been lacking. The Swedish Obese Subjects (SOS) study is the first long-term, prospective, controlled trial to provide information on the effects of bariatric surgery on the incidence of these objective endpoints. The SOS study involved 2010 obese subjects who underwent bariatric surgery [gastric bypass (13%), banding (19%) and vertical banded gastroplasty (68%)] and 2037 contemporaneously matched obese control subjects receiving usual care. The age of participants was 37-60 years and body mass index (BMI) was ≥34 kg m(-2) in men and ≥38 kg m(-2) in women. Here, we review the key SOS study results published between 2004 and 2012. Follow-up periods varied from 10 to 20 years in different reports. The mean changes in body weight after 2, 10, 15 and 20 years were -23%, -17%, -16% and -18% in the surgery group and 0%, 1%, -1% and -1% in the control group respectively. Compared with usual care, bariatric surgery was associated with a long-term reduction in overall mortality (primary endpoint) [adjusted hazard ratio (HR) = 0.71, 95% confidence interval (CI) 0.54-0.92; P = 0.01] and decreased incidences of diabetes (adjusted HR=0.17; P < 0.001), myocardial infarction (adjusted HR = 0.71; P = 0.02), stroke (adjusted HR=0.66; P = 0.008) and cancer (women: adjusted HR = 0.58; P = 0.0008; men: n.s.]. The diabetes remission rate was increased severalfold at 2 years [adjusted odds ratio (OR) = 8.42; P < 0.001] and 10 years (adjusted OR = 3.45; P < 0.001). Whereas high insulin and/or high glucose at baseline predicted favourable treatment effects, high baseline BMI did not, indicating that current selection criteria for bariatric surgery need to be revised.

Repeated Weight Loss is Associated with the Metabolic Syndrome and Diabetes: Results of a 28 Year Re-screening of Men in the Oslo Study

OBJECTIVE

We investigated whether weight loss episodes were associated with the metabolic syndrome and diabetes in elderly men.

DESIGN AND SUBJECTS

Men residing in Oslo and born in 1923-32 (n = 16,209) were screened for cardiovascular diseases and risk factors in 1972-73. Those who resided in the same area in the year 2000 were invited to a repeat physical and laboratory examination, attended by 6 410 men (mean age 72.5 years). Weight, height and blood pressure were measured both times, and a non-fasting measurements of total serum cholesterol, triglycerides and glucose were obtained. Weight loss, leisure time physical activity, smoking habits, and educational attendance were self-reported.

RESULTS

The proportion that reported one or more episodes of weight loss at age 25-50 years was 15.6% (n = 3,564 respondents) while 26.8% reported weight loss after age 50 (n = 3,473 respondents). Age-specific weight loss scores based on the number of the episodes of weight loss or on the total amount of weight loss were strongly associated with the presence of obesity, the metabolic syndrome and diabetes in the year 2000. The risk of the metabolic syndrome and diabetes in 2000 increased with increasing number of weight loss episodes also adjusted for BMI in 1972-73 and other potential confounders. The odds ratio for the metabolic syndrome for one standard deviation change in the number of weight loss episodes after age 50 was 1.43 (95% confidence limits 1.30-1.57). The corresponding odds ratio for diabetes was 1.25 (95% confidence limits 1.14-1.37). Similar results were found using a score for the total amount of weight loss.

CONCLUSION

Among elderly men the number of episodes or amount of weight loss after age 50 was associated with the metabolic syndrome and diabetes, but this study cannot establish the causality of the association.

A systematic review of the impact of weight loss on cancer incidence and mortality

Obesity is well recognized as a significant risk factor for certain cancers; however, a corresponding risk reduction with weight loss is not yet clearly defined. This review aims to examine the literature investigating the effect of all types of weight loss on cancer incidence and mortality, and to more clearly describe the relationship between these two factors. A literature search identified 34 publications reporting weight loss data in relation to cancer incidence or mortality. All except one were observational studies and the majority used self-reported weights and did not define intentionality of weight loss. 16/34 studies found a significant inverse association between weight loss and cancer incidence or mortality. The remainder returned null findings. The observed association was more consistently seen in studies that investigated the effect of intentional weight loss (5/6 studies) and the risk reduction was greatest for obesity-related cancers and in women. In conclusion, intentional weight loss does result in a decreased incidence of cancer, particularly female obesity-related cancers. However, there is a need for further evaluation of sustained intentional weight loss in the obese with less reliance on self-reported weight data and more focus on male populations.

Obesity in Older Adults: Technical Review and Position Statement of the American Society for Nutrition and NAASO, The Obesity Society

Obesity causes serious medical complications and impairs quality of life. Moreover, in older persons, obesity can exacerbate the age-related decline in physical function and lead to frailty. However, appropriate treatment for obesity in older persons is controversial because of the reduction in relative health risks associated with increasing body mass index and the concern that weight loss could have potential harmful effects in the older population. This joint position statement from the American Society for Nutrition and NAASO, The Obesity Society reviews the clinical issues related to obesity in older persons and provides health professionals with appropriate weight-management guidelines for obese older patients. The current data show that weight-loss therapy improves physical function, quality of life, and the medical complications associated with obesity in older persons. Therefore, weight-loss therapy that minimizes muscle and bone losses is recommended for older persons who are obese and who have functional impairments or medical complications that can benefit from weight loss.

Obesity: a disease or a biological adaptation? An update

Obesity is characterized by the accumulation of excess body fat and can be conceptualized as the physical manifestation of chronic energy excess. An important challenge of today's world is that our so-called obesogenic environment is conducive to the consumption of energy and unfavourable to the expenditure of energy. The modern, computer-dependent, sleep-deprived, physically inactive humans live chronically stressed in a society of food abundance. From a physiological standpoint, the excess weight gain observed in prone individuals is perceived as a normal consequence to a changed environment rather than a pathological process. In other words, weight gain is a sign of our contemporary way of living or a 'collateral damage' in the physiological struggle against modernity. Additionally, substantial body fat loss can complicate appetite control, decrease energy expenditure to a greater extent than predicted, increase the proneness to hypoglycaemia and its related risk towards depressive symptoms, increase the plasma and tissue levels of persistent organic pollutants that promote hormone disruption and metabolic complications, all of which are adaptations that can increase the risk of weight regain. In contrast, body fat gain generally provides the opposite adaptations, emphasizing that obesity may realistically be perceived as an a priori biological adaptation for most individuals. Accordingly, prevention and treatment strategies for obesity should ideally target the main drivers or root causes of body fat gain in order to be able to improve the health of the population.

Pleiotropic effects of incretins

Drugs that augment the incretin system [glucagon like peptide (GLP) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors] represent a novel class of anti-hyperglycemic agents that have shown to improve the health and survival of beta-cells (improvement in postprandial hyperglycemia) and suppress glucagon (improvement in fasting hyperglycemia). The incretins represent a large family of molecules referred to as the "glucagon superfamily of peptide hormones" of which more than 90% of the physiological effects of incretins are accomplished by GLP-1(7-37) and GLP1(7-36) amide and gastric insulinotropic peptide (GIP). GLP-1 mediates its effects via the GLP-1 receptor, which has a wide tissue distribution [pancreas, lung, heart, vascular smooth muscle cells, endothelial cells, macrophages and monocytes, kidney, gastrointestinal tract (stomach and intestine), central nervous system (neoortex, cerebellum, hypothalamus, hippocampus, brainstem nucleus tractus solitarius) and peripheral nervous system]. This would imply that the incretin system has effects outside the pancreas. Over time data has accumulated to suggest that therapies that augment the incretin system has beneficial pleiotrophic effects. The incretins have shown to possess a cardiac-friendly profile, preserve neuronal cells and safeguard from neuronal degeneration, improve hepatic inflammation and hepatosteatosis, improve insulin resistance, promote weight loss and induce satiety. There is growing evidence that they may also be renoprotective promoting wound healing and bone health.

The effect of intentional weight loss on all-cause mortality in older adults: results of a randomized controlled weight-loss trial

BACKGROUND

Despite the reported benefits, weight loss is not always advised for older adults because some observational studies have associated weight loss with increased mortality. However, the distinction between intentional and unintentional weight loss is difficult to make in an observational context, so the effect of intentional weight loss on mortality may be clarified in the setting of a randomized controlled trial.

OBJECTIVE

The objective was to determine the effect of intentional weight loss on all-cause mortality by using follow-up data from a randomized trial completed in 1995 that included a weight-loss arm.

DESIGN

The Trial of Nonpharmacologic Intervention in the Elderly (TONE) used a 2 × 2 factorial design to determine the effect of dietary weight loss, sodium restriction, or both on blood pressure control in 585 overweight or obese older adults being treated for hypertension (mean ± SD age: 66 ± 4 y; 53% female). All-cause mortality was ascertained by using the Social Security Index and National Death Index through 2006.

RESULTS

The mortality rate of those who were randomly assigned to the weight-loss intervention (n = 291; mean weight loss: 4.4 kg) did not differ significantly from that of those who were not randomly assigned to this group (n = 294; mean weight loss: 0.8 kg). The adjusted HR was 0.82 (95% CI: 0.55, 1.22).

CONCLUSIONS

Intentional dietary weight loss was not significantly associated with increased all-cause mortality over 12 y of follow-up in older overweight or obese adults. Additional studies are needed to confirm and extend our findings to older age groups. This trial is registered at clinicaltrials.gov as NCT00000535.

Diabetes resolution and hyperinsulinaemia after metabolic Roux-en-Y gastric bypass

The global prevalence of type 2 diabetes mellitus and impaired glucose metabolism continues to rise in conjunction with the pandemic of obesity. The metabolic Roux-en-Y gastric bypass operation offers the successful resolution of diabetes in addition to sustained weight loss and excellent long-term outcomes in morbidly obese individuals. The procedure consists of the physiological BRAVE effects: (i) Bile flow alteration; (ii) Reduction of gastric size; (iii) Anatomical gut rearrangement and altered flow of nutrients; (iv) Vagal manipulation and (v) Enteric gut hormone modulation. This operation provides anti-diabetic effects through decreasing insulin resistance and increasing the efficiency of insulin secretion. These metabolic outcomes are achieved through weight-independent and weight-dependent mechanisms. These include the foregut, midgut and hindgut mechanisms, decreased inflammation, fat, adipokine and bile metabolism, metabolic modulation, shifts in gut microbial composition and intestinal gluconeogenesis. In a small minority of patients, gastric bypass results in hyperinsulinaemic hypoglycaemia that may lead to nesidioblastosis (pancreatic beta-cell hypertrophy with islet hyperplasia). Elucidating the precise metabolic mechanisms of diabetes resolution and hyperinsulinaemia after surgery can lead to improved operations and disease-specific procedures including 'diabetes surgery'. It can also improve our understanding of diabetes pathogenesis that may provide novel strategies for the management of metabolic syndrome and impaired glucose metabolism.

Obesity paradox in elderly patients with cardiovascular diseases

Many elderly people are affected by cardiovascular diseases (CVD) and the majority of CVD patients are elderly people. For both patient populations, studies have shown that a high body mass index (BMI) is associated with lower mortality when compared to normal weight subjects, a fact commonly known as the "obesity paradox". Whether the correlation between obesity and better survival is based on methodological influences and other non-causal factors alone, or whether there is a causal link between obesity and a better survival in these subjects remains widely unexplored. The interrelation between aging, obesity, CVD, frailty and inflammation is a current issue of intensive research. For the elderly, parameters which include measures of body composition, fat and fat-free mass are of greater importance than BMI. Weight management in elderly people with cardiovascular diseases should aim at improvement and maintenance of physical function and quality of life rather than prevention of medical problems associated with obesity in younger and middle aged patients. Although many studies have shown that weight loss in elderly patients is associated with a poor prognosis, recent data demonstrate that intentional weight reduction in obese elderly people ameliorates the cardiovascular risk profile, reduces chronic inflammation and is correlated with an improved quality of life. An individual approach to weight management that includes the participation of the patient, co-morbidity, functional status, and social support should be aspired.

Weight science: evaluating the evidence for a paradigm shift

Current guidelines recommend that "overweight" and "obese" individuals lose weight through engaging in lifestyle modification involving diet, exercise and other behavior change. This approach reliably induces short term weight loss, but the majority of individuals are unable to maintain weight loss over the long term and do not achieve the putative benefits of improved morbidity and mortality. Concern has arisen that this weight focus is not only ineffective at producing thinner, healthier bodies, but may also have unintended consequences, contributing to food and body preoccupation, repeated cycles of weight loss and regain, distraction from other personal health goals and wider health determinants, reduced self-esteem, eating disorders, other health decrement, and weight stigmatization and discrimination. This concern has drawn increased attention to the ethical implications of recommending treatment that may be ineffective or damaging. A growing trans-disciplinary movement called Health at Every Size (HAES) challenges the value of promoting weight loss and dieting behavior and argues for a shift in focus to weight-neutral outcomes. Randomized controlled clinical trials indicate that a HAES approach is associated with statistically and clinically relevant improvements in physiological measures (e.g., blood pressure, blood lipids), health behaviors (e.g., eating and activity habits, dietary quality), and psychosocial outcomes (such as self-esteem and body image), and that HAES achieves these health outcomes more successfully than weight loss treatment and without the contraindications associated with a weight focus. This paper evaluates the evidence and rationale that justifies shifting the health care paradigm from a conventional weight focus to HAES.

Interpreting the epidemiological evidence linking obesity and cancer: A framework for population-attributable risk estimations in Europe

Standard approaches to estimating population-attributable risk (PAR) include modelling estimates of exposure prevalence and relative risk. Here, we examine the associations between body mass index (BMI) and cancer risk and how effect modifications of these associations impact on PAR estimates. In 2008, sex- and population-specific risk estimates were determined for associations with BMI in a standardised meta-analysis for 20 cancer types. Since then, refinements of these estimates have emerged: (i) absence of menopausal hormonal therapy (MHT) is associated with elevated BMI associations in post-menopausal breast, endometrial and ovarian cancers; (ii) current smoking attenuates the BMI associations in oesophageal squamous cell carcinoma, lung and pancreatic cancers; (iii) prostate screening attenuates BMI associations when all prostate cancers are considered together; and (iv) BMI is differentially associated with different histological subtypes within the same cancer group. Using secondary analyses of the aforementioned meta-analysis, we show 2-3-fold shifts in PAR estimations for breast and endometrial cancers depending on the MHT usage in European countries. We also critically examine how to best handle exposures (in this example, BMI distributions) and relative risk estimates in PAR models, and argue in favour of a counterfactual approach based around BMI means. From these observations, we develop a research framework in which to optimally evaluate future trends in numbers of new cancers attributable to excess BMI. Overall, this framework gives conservative estimates for PAR - nonetheless, the numbers of avoidable cancers across Europe through avoidance of excess weight are substantial.