Intentional weight loss and mortality among initially healthy men and women

A synthesis of pathways linking diet, metabolic risk and cardiovascular disease: a framework to guide further research and approaches to evidence-based practice

Cardiovascular disease (CVD) is the most common non-communicable disease occurring globally. Although previous literature has provided useful insights into the important role that diet plays in CVD prevention and treatment, understanding the causal role of diets is a difficult task considering inherent and introduced weaknesses of observational (e.g. not properly addressing confounders and mediators) and experimental research designs (e.g. not appropriate or well designed). In this narrative review, we organised current evidence linking diet, as well as conventional and emerging physiological risk factors, with CVD risk, incidence and mortality in a series of diagrams. The diagrams presented can aid causal inference studies as they provide a visual representation of the types of studies underlying the associations between potential risk markers/factors for CVD. This may facilitate the selection of variables to be considered and the creation of analytical models. Evidence depicted in the diagrams was systematically collected from studies included in the British Nutrition Task Force report on diet and CVD and database searches, including Medline and Embase. Although several markers and disorders linked to conventional and emerging risk factors for CVD were identified, the causal link between many remains unknown. There is a need to address the multifactorial nature of CVD and the complex interplay between conventional and emerging risk factors with natural and built environments, while bringing the life course into the spotlight.

Association Between Weight Change During Adulthood and Chronic Kidney Disease: Results from a National Survey 2011-2018

Purpose

This study aimed to investigate the intricate relationship between weight change patterns and the onset of chronic kidney disease (CKD). Although obesity is recognized as a predisposing factor for CKD, the dynamics of weight fluctuation and its impact on CKD development are not well-defined. By analyzing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011 to 2018, we sought to elucidate the association between weight trajectories and CKD risk.

Patients and Methods

We included participants aged ≥40 years, employing body mass index (BMI) measurements at three life stages-baseline, age 25, and a decade preceding baseline-to categorize weight change patterns. Logistic regression was employed to evaluate the association of these patterns with CKD onset, adjusting for potential confounders.

Results

The study encompassed 12,284 participants, with 2893 individuals diagnosed with CKD. Transitioning from normal weight to obesity and staying obese throughout adulthood were found to increase the risk of developing CKD. These associations remained consistent after adjusting for covariates but were statistically insignificant after adjusting for comorbidities. Notably, individuals transitioning from obesity to normal weight from age 25 to baseline and from 10 years before baseline to baseline demonstrated significant correlations with CKD but not between age 25 and 10 years before baseline.

Conclusion

Obesity, weight gain throughout adulthood, and weight loss in middle-to-late adulthood are associated with an increased risk of CKD. This emphasizes the importance of long-term weight change patterns and maintaining a healthy weight throughout adulthood.

Anthropometric measures and risk of all-cause and cardiovascular mortality: An 18 years follow-up

BACKGROUND

The contribution of anthropometric measures to predict mortality in normal-weight subjects is unclear. We aimed to study the association of central obesity measures, e.g., waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), with the risk of all-cause and CVD mortality.

METHODS

In a prospective population-based Tehran Lipid and Glucose Study, 8287 participants aged ≥30 y, followed for a median of 18 years. The association of WC, WHR and WHtR with the risk for mortality was estimated using multivariate Cox proportional hazard models in different BMI groups.

RESULTS

We documented 821 deaths, of which 251 were related to CVD mortality. Normal weight individuals with central obesity were significantly at increased risk of all-cause (HR: 1.5; 95% CI: 1.10, 2.1) and CVD mortality (HR: 1.6; 95% CI: 0.92, 2.9) compared with normal-weight individuals without central obesity; the risk remained significant only in women. Also, normal-weight women (not men) with high WHR were at increased risk of all-cause (HR: 1.7; 95% CI: 1.0, 2.8) and CVD mortality (HR: 5.9; 95% CI: 1.5, 23.2). High WHtR increased the risk of all-cause (HR: 1.5; 95% CI: 1.2, 1.8) and CVD mortality (HR: 1.8; 95% CI: 1.2, 2.7) which remained significant in normal-weight men and women. All central obesity indicators were significantly associated with all-cause and CVD mortality in subjects aged under 65.

CONCLUSION

Even in normal-weight individuals, WC and WHR in women and WHtR in both sexes are predictors of all-cause and CVD mortality. WHtR shows a stronger association, especially in the population aged under 65.

Life-long body mass index trajectories and mortality in two generations

PURPOSE

To identify life-long body mass index (BMI) trajectories across two related generations and estimate their associated mortality risks and population attributable deaths.

METHODS

We use prospective cohort data from the Framingham Heart Study (1948-2011) original (4576 individuals, 3913 deaths) and offspring (3753 individuals, 967 deaths) cohorts and latent trajectory models to model BMI trajectories from age 31 to 80 years. Survival models are used to estimate trajectory-specific mortality risk.

RESULTS

We define seven BMI trajectories among original cohort and six among offspring cohort. Among original cohort, people who are normal weight at age 31 years and gradually move to overweight status in middle or later adulthood have the lowest mortality risk even compared to those who maintain normal weight throughout adulthood, followed by overweight stable, lower level of normal weight, overweight downward, class I obese upward, and class II/III upward trajectories. Mortality risks associated with obesity trajectories have declined across cohorts, while the prevalence of high-risk trajectories has increased.

CONCLUSIONS

The mortality impact of weight gain depends on an individual's BMI trajectory. Population attributable deaths associated with unhealthy weight trajectories have grown over generations because the prevalence has increased, offsetting the decline in trajectory-specific mortality risks.

Relation of Change of Body Mass Index to Long-Term Mortality After Cardiac Catheterization

Body-mass index (BMI) is a risk marker and therapeutic target in cardiovascular prevention. The effect of changes in BMI on mortality in patients with cardiovascular diseases has not been completely delineated. We aimed to assess the association between percent change in BMI, as measured 3-years after cardiac catheterization, and long-term mortality. Patients who underwent cardiac catheterization (n = 11,220; mean age 63 ± 10 years) were categorized according to BMI groups (normal-weight, 18.50 to 24.99 kg/m²; overweight, 25.00 to 29.99 kg/m²; obesity, ≥30 kg/m²). Follow-up BMI was considered the level measured closest to the timepoint of 3 years post catheterization. Percent change in BMI was calculated and its association with long-term all-cause mortality was investigated. Change in BMI of ±5% was observed in 46% of the patients, a decrease >5% in 15.5%, and an increase of >5% of BMI in 38.5%. Compared with those with the lowest change in BMI (±5%), the adjusted hazard ratios for mortality were 1.45 (95% confidence interval [CI], 1.27 to 1.65), and 1.69 (1.46 to 1.95) in patients with 5% to 10% and >10% decrease in BMI, respectively, and 1.05 (0.94 to 1.17), 1.15 (1.03 to 1.28), and 1.40 (1.19 to 1.64) in patients with 5% to 10%, 10% to 20% and >20% increase in BMI, respectively. The pattern was similar in normal-weight, overweight, and obese subgroups at baseline. However, the magnitude of the association with decrease BMI was more pronounced in normal-weight patients (P-for-interaction 0.031). In conclusion, the association of percent changes in BMI after cardiac catheterization and all-cause mortality had a reversed J-shaped pattern, with both weight loss and weight gain being associated with increased risk. A decrease in BMI was related to higher mortality rates than was an increase in BMI for a comparable degree of percent change.

Changes in body image during a 6-month lifestyle behaviour intervention in a sample of overweight and obese individuals

BACKGROUND

Individuals with long-term chronic body image dissatisfaction may experience excessive stress and negative cognitions and feelings. Changes in negative cognition about body image are often reported as outcomes of obesity treatment. In turn, body image dissatisfaction also influences behavioural adherence and success in weight loss.

OBJECTIVES

The purpose of the present study was to elucidate psychological changes during 6 months of lifestyle behaviour intervention and the association of these changes with actual weight loss.

METHODS

The study examined associations between body image dissatisfaction and obesity treatment-related variables among 33 overweight and obese adults (age = 38.9 ± 6.5 years) participating in a 6-month diet and exercise weight loss intervention. Measurements of body image dissatisfaction and anthropometric variables were taken at baseline and after 6-months.

DISCUSSION

Significant improvements were observed in all physical variables (e.g. weight, percentage of body fat mass, waist and hip circumference) after intervention. Body image dissatisfaction improved significantly over the treatment, and these changes were associated with changes in obesity indicators.

CONCLUSIONS

Changes in weight and body image probably influence each other dynamically. Results from this study support the inclusion of cognitive intervention aimed at improving body image in weight management programs.

Self-reported Intentional Weight Loss and Risk of Death in Moderate Chronic Kidney Disease in the United States

OBJECTIVE

We hypothesized that intentional weight loss is associated with lower mortality risk, whereas unintentional weight loss is associated with higher mortality risk in chronic kidney disease (CKD).

DESIGN AND METHODS

We examined this hypothesis in 872 participants with age >20 years, body mass index ≥ 25 kg/m2 and CKD from 1999-2004 National Health and Nutrition Examination Survey who reported their 1 year prior and current weights and the intent to lose weight. We examined the association of self-reported intentional versus unintentional weight loss with all-cause mortality. Participants with no intent to lose weight and no change in weight were the reference group. A multivariable Cox regression model was used to relate mortality with intentional and unintentional weight losses after adjustment for demographics and comorbidity.

RESULTS

There were 446 deaths over 6271 years of follow-up. Compared to the reference group, intentional weight loss of 5% to <10% (hazard ratio (HR) 1.22, 95% confidence interval (CI): 0.74-1.99), intentional weight loss of ≥10% (HR 1.53, 95% CI: 0.75-3.12), and unintentional weight loss of 5% to <10% (HR 1.11, 95% CI: 0.71-1.75) were not associated with mortality; however, unintentional weight loss of ≥10% (HR 1.66, 95% CI: 1.06-2.58) was significantly associated with higher risk of mortality. Retrospective design and self-reported weight loss were the limitations.

CONCLUSIONS

Intentional weight loss in CKD participants was not associated with lower mortality risk. This might reflect residual confounding. Mechanistic and interventional studies are warranted to determine the effects of intentional weight loss in CKD.

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.

Change in body size and mortality: a systematic review and meta-analysis

Background

: Observational studies have reported that weight loss in later life is associated with an increased risk of mortality. However, the association with weight gain is unclear. We conducted a systematic review and meta-analysis of prospective studies assessing the association of weight gain and loss, and mortality.

Methods

: We searched PubMed, Scopus and Web of Science for articles published before 5 September 2015. We included prospective studies that reported enough information to extract hazard ratios (HRs) with the corresponding 95% confidence intervals (CIs) for the association between weight gain and/or weight loss, and all-cause and cause-specific mortality. The estimates were pooled using a random-effects model. Meta-regression models were fitted to explore sources of potential between-study heterogeneity.

Results

: A total of 25 (providing data from 437 772 participants with 34 038 deaths from all causes) and 24 studies (434 694 participants with 31 978 deaths) presented results for the exposures, weight loss and weight gain. Weight loss compared with a stable weight was associated with an increased risk of all-cause (pooled HR: 1.45; 95% CI: 1.34, 1.58), and cardiovascular disease (CVD) mortality (1.50; 1.32, 1.70) and a slightly increased risk of cancer mortality (1.19; 0.97, 1.46). Weight gain was associated with an increased risk of CVD mortality (1.21; 1.07, 1.36) and a slightly increased risk of all-cause mortality (1.07; 1.01, 1.13) and cancer mortality (1.04; 0.96, 1.13). Considerable heterogeneity was observed; the method used to ascertain body size and the proportion of the baseline sample included in the final analysis explained most of the heterogeneity.

Conclusion

: Weight loss and weight gain in midlife are associated with increased risk of all-cause and CVD mortality.

Weight change in older adults and mortality: the Multiethnic Cohort Study

Objective

To investigate the association between weight change in older adults and mortality in a multiethnic population.

Methods

We performed a prospective analysis using data on weight change between the baseline (1993-1996) and the 10-year follow-up (2003-2007) surveys in relation to subsequent mortality among 63,040 participants in the Multiethnic Cohort Study in Hawaii and California. The participants were African American, Native Hawaiian, Japanese American, Latino, and white, aged 45-75 years at baseline, and did not report heart disease or cancer at either survey.

Results

During an average of 7.3 years of follow-up after the 10-year survey, 6,623 deaths were identified. Compared with individuals whose weight remained stable (±2.5 kg), those who lost weight and those with the highest weight gain (>10 kg) were at increased risk of all-cause mortality, with the risks greater for the weight-loss (hazard ratios [HR], 2.86; 95% confidence interval [95% CI], 2.62-3.11 for >10 kg) than the weight-gain group (HR, 1.25; 95% CI, 1.11-1.41 for >10 kg), thus resulting in a reverse J-shaped curve. Japanese Americans and Latinos had stronger associations of weight loss >10 kg with mortality than did African Americans, Native Hawaiians, and whites. The increase in risk with weight gain >10 kg was greater for older (≥55 years at baseline) than younger individuals while the increase in mortality associated with weight loss was greater for the normal weight (<25 kg/m² at baseline) participants and never smokers, compared with overweight/obese persons and current smokers, respectively.

Conclusions

Our findings confirm the association between weight change and a higher mortality in a healthy, multiethnic population, with higher risks for weight loss than weight gain. Based on these observations, public health recommendation should focus on the prevention of weight loss, as well as weight stability within the non-obese range, for middle aged and older adults.

Weight Change and Risk of Venous Thromboembolism: The Tromsø Study

BACKGROUND

Obesity is a major risk factor for venous thromboembolism (VTE), but it is unknown to what extent weight change over time affects VTE risk.

AIMS

To investigate the association between weight change and risk of incident VTE in a population-based cohort with repeated measurements.

METHODS

Participant data were collected from the Tromsø 3 (1986-87), 4 (1994-95), 5 (2000-01) and 6 (2007-08) surveys. Subjects who attended two subsequent or more surveys were included (n = 17802), and weight change between the surveys was calculated. Person-time at risk was accrued from the second of two subsequent vists until the next survey, the date of an incident VTE, migration, death or study end (December 31st 2012), whichever came first. Cox regression models were used to calculate risk of VTE according to change in body weight.

RESULTS

There were 302 incident VTE events during a median of 6.0 years of follow-up. Subjects who gained most weight (7.5-40.0 kg weight gain) had a 1.9-fold higher risk of VTE compared to those with no or a moderate (0-7.4 kg) weight gain (HR 1.92; 95% CI 1.38-2.68). The VTE risk by ≥7.5 kgs over no or moderate (0-7.4 kg) weight gain was highest (HR 3.75; 95% 1.83-7.68) in subjects with baseline body mass index (BMI) ≥30 kg/m2. There was a joint effect of weight gain and baseline BMI on VTE risk. Those with BMI ≥30 who gained ≥7.5 kgs had a 6.6-fold increased risk (HR 6.64; 95% CI 3.61-12.22) compared to subjects with BMI <25 and no or moderate (0-7.4 kg) weight gain.

CONCLUSIONS

Our findings imply that further weight gain is a considerable risk factor for VTE, particularly in obese individuals.

Participation in a Structured Weight Loss Program and All-Cause Mortality and Cardiovascular Morbidity in Obese Patients With Chronic Kidney Disease

OBJECTIVE

To determine if participation in a weight loss program impacted upon a composite end point of all-cause mortality and cardiovascular morbidity in obese patients with chronic kidney disease (CKD).

DESIGN

Retrospective cohort study.

SUBJECTS

All patients with a body mass index (BMI) >30 kg/m(2) or >28 kg/m(2) with at least 1 comorbidity (hypertension, diabetes, or dyslipidemia) referred to an established weight management program (WMP) from 2005 to 2009 at a metropolitan tertiary teaching hospital were eligible for inclusion in the study cohort.

INTERVENTION

Twelve-month structured weight loss program.

MAIN OUTCOME MEASURES

Combined outcome of all-cause mortality, myocardial infarction, stroke, and hospitalization for congestive heart failure; kidney transplantation waitlisting.

RESULTS

A total of 169 obese patients with CKD commenced the WMP and 169 did not-becoming the observational control group (CON). There were no significant differences between groups for age, BMI, sex, ethnicity, smoking, hypertension, or kidney function at baseline, although CON included more patients with diabetes than WMP (49% vs. 38%, P = .03). Kaplan-Meier survival analysis with log-rank test differed between groups for the combined outcome (P = .03). Cox regression analysis with adjustment for age, sex, ethnicity, hypertension, diabetes, kidney function, baseline BMI, and smoking status, indicated that patients in WMP had a significantly longer event-free period for the combined outcome, than those in CON (adjusted hazard ratio 0.53; 95% confidence interval [CI] 0.29-0.97; P = .04). Participation in the WMP did not increase the likelihood of kidney transplantation waitlisting (odds ratio [OR] 1.06; 95% CI 0.39-2.87; P = .9). Lower baseline BMI and greater weight loss over 12 months were the only factors related to kidney transplantation waitlisting (adjusted R(2) = 0.426).

CONCLUSIONS

Participation in a structured weight loss program may be associated with improved outcomes in obese patients with CKD.

Weight Change and All-Cause Mortality in Older Adults: A Meta-Analysis

This meta-analysis of observational cohort studies examined the association between weight change (weight loss, weight gain, and weight fluctuation) and all-cause mortality among older adults. We used Pub Med (MEDLINE), Web of Science, and Cochrane Library to identify prospective studies published in English from inception to November 2014. Seventeen prospective studies met the inclusion criteria and were included in this meta-analysis. Higher all-cause mortality risks were noted with weight change: weight loss (pooled RR, 1.67; 95% CI, 1.51-1.85; p < 0.001 for heterogeneity), weight gain (pooled RR, 1.21; 95% CI, 1.09-1.33; p = 0.03 for heterogeneity), and weight fluctuation (pooled RR, 1.53; 95% CI, 1.36-1.72; p = 0.43 for heterogeneity). Similar results were observed with stricter criteria for sensitivity analyses. None of the study characteristics had statistically significant effects on the pooled RR, except for study quality on weight loss. Weight change is associated with higher mortality risk among community-dwelling adults 60 years and older.

Change in body size and mortality: results from the Melbourne collaborative cohort study

BACKGROUND

The association between change in weight or body mass index, and mortality is widely reported, however, both measures fail to account for fat distribution. Change in waist circumference, a measure of central adiposity, in relation to mortality has not been studied extensively.

METHODS

We investigated the association between mortality and changes in directly measured waist circumference, hips circumference and weight from baseline (1990-1994) to wave 2 (2003-2007) in a prospective cohort study of people aged 40-69 years at baseline. Cox regression, with age as the time metric and follow-up starting at wave 2, adjusted for confounding variables, was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for change in body size in relation to mortality from all causes, cardiovascular disease and cancer.

RESULTS

There were 1465 deaths (109 cancer, 242 cardiovascular disease) identified during an average 7.7 years of follow-up from 21 298 participants. Compared to minimal increase in body size, loss of waist circumference (HR: 1.26; 95% CI: 1.09-1.47), weight (1.80; 1.54-2.11), or hips circumference (1.35; 1.15-1.57) were associated with an increased risk of all-cause mortality, particularly for older adults. Weight loss was associated with cardiovascular disease mortality (2.40; 1.57-3.65) but change in body size was not associated with obesity-related cancer mortality.

CONCLUSION

This study confirms the association between weight loss and increased mortality from all-causes for older adults. Based on evidence from observational cohort studies, weight stability may be the recommended option for most adults, especially older adults.

Obesity and mortality risk: new findings from body mass index trajectories

Little research has addressed the heterogeneity and mortality risk in body mass index (BMI) trajectories among older populations. Applying latent class trajectory models to 9,538 adults aged 51 to 77 years from the US Health and Retirement Study (1992-2008), we defined 6 latent BMI trajectories: normal weight downward, normal weight upward, overweight stable, overweight obesity, class I obese upward, and class II/III obese upward. Using survival analysis, we found that people in the overweight stable trajectory had the highest survival rate, followed by those in the overweight obesity, normal weight upward, class I obese upward, normal weight downward, and class II/III obese upward trajectories. The results were robust after controlling for baseline demographic and socioeconomic characteristics, smoking status, limitations in activities of daily living, a wide range of chronic illnesses, and self-rated health. Further analysis suggested that BMI trajectories were more predictive of mortality risk than was static BMI status. Using attributable risk analysis, we found that approximately 7.2% of deaths after 51 years of age among the 1931-1941 birth cohort were due to class I and class II/III obese upward trajectories. This suggests that trajectories of increasing obesity past 51 years of age pose a substantive threat to future gains in life expectancy.

Changes in fitness and fatness on the development of cardiovascular disease risk factors hypertension, metabolic syndrome, and hypercholesterolemia

OBJECTIVES

This study sought examine the independent and combined associations of changes in fitness and fatness with the subsequent incidence of the cardiovascular disease (CVD) risk factors of hypertension, metabolic syndrome, and hypercholesterolemia.

BACKGROUND

The relative and combined contributions of fitness and fatness to health are controversial, and few studies are available on the associations of changes in fitness and fatness with the development of CVD risk factors.

METHODS

We followed up 3,148 healthy adults who received at least 3 medical examinations. Fitness was determined by using a maximal treadmill test. Fatness was expressed by percent body fat and body mass index. Changes in fitness and fatness between the first and second examinations were categorized into loss, stable, or gain groups.

RESULTS

During the 6-year follow-up after the second examination, 752, 426, and 597 adults developed hypertension, metabolic syndrome, and hypercholesterolemia, respectively. Maintaining or improving fitness was associated with lower risk of developing each outcome, whereas increasing fatness was associated with higher risk of developing each outcome, after adjusting for possible confounders and fatness or fitness for each other (all p for trend <0.05). In the joint analyses, the increased risks associated with fat gain appeared to be attenuated, although not completely eliminated, when fitness was maintained or improved. In addition, the increased risks associated with fitness loss were also somewhat attenuated when fatness was reduced.

CONCLUSIONS

Both maintaining or improving fitness and preventing fat gain are important to reduce the risk of developing CVD risk factors in healthy adults.

Long-term effects of changes in cardiorespiratory fitness and body mass index on all-cause and cardiovascular disease mortality in men: the Aerobics Center Longitudinal Study

BACKGROUND

The combined associations of changes in cardiorespiratory fitness and body mass index (BMI) with mortality remain controversial and uncertain.

METHODS AND RESULTS

We examined the independent and combined associations of changes in fitness and BMI with all-cause and cardiovascular disease (CVD) mortality in 14 345 men (mean age 44 years) with at least 2 medical examinations. Fitness, in metabolic equivalents (METs), was estimated from a maximal treadmill test. BMI was calculated using measured weight and height. Changes in fitness and BMI between the baseline and last examinations over 6.3 years were classified into loss, stable, or gain groups. During 11.4 years of follow-up after the last examination, 914 all-cause and 300 CVD deaths occurred. The hazard ratios (95% confidence intervals) of all-cause and CVD mortality were 0.70 (0.59-0.83) and 0.73 (0.54-0.98) for stable fitness, and 0.61 (0.51-0.73) and 0.58 (0.42-0.80) for fitness gain, respectively, compared with fitness loss in multivariable analyses including BMI change. Every 1-MET improvement was associated with 15% and 19% lower risk of all-cause and CVD mortality, respectively. BMI change was not associated with all-cause or CVD mortality after adjusting for possible confounders and fitness change. In the combined analyses, men who lost fitness had higher all-cause and CVD mortality risks regardless of BMI change.

CONCLUSIONS

Maintaining or improving fitness is associated with a lower risk of all-cause and CVD mortality in men. Preventing age-associated fitness loss is important for longevity regardless of BMI change.

Longitudinal evaluation of cancer-associated biomarkers before and after weight loss in RENEW study participants: implications for cancer risk reduction

INTRODUCTION

Obesity is a major risk factor for the development of endometrial cancer (EC). An improved understanding of biologic mechanisms associated with weight loss, including alteration in inflammation, hormonal balance, and cancer antigens expression may lead to the development of effective cancer prevention strategies. The goal of this study was to explore longitudinal biomarker changes in obese women who underwent weight loss intervention, testing the hypothesis biomarker levels can be altered through intentional weight loss.

METHODS

Serum samples from 89 participants with Class II and Class III obesity and 43 non morbidly obese comparisons were obtained in Re-Energize with Nutrition, Exercise and Weight Loss (RENEW) study as previously reported. Twenty-one bead-based xMAP immunoassays were utilized, including cancer-associated antigens, cytokines, chemokines, and hormones. One-way repeated measures ANOVA was used to examine the association between changes in biomarker expression levels over time (baseline, 6 months and 12 months). Linear mixed effects models were used to examine longitudinal relationships between biomarker expression levels.

RESULTS

Mean levels of VEGF, soluble E-selectin, GH, adiponectin, IL-6, IL-7, CA-125, and IGFBP-1 significantly differed between time periods. In adjusted mixed linear models, decreasing BMI was significantly associated with lower levels of soluble E-selectin and IL-6 and increases in GH, adiponectin, and IGFBP-1.

CONCLUSIONS

This is one of the first efforts to explore changes in cancer-associated biomarkers in a cohort of weight loss research participants at high risk for EC development. Our findings demonstrate that changes in the expression of markers can be achieved with weight loss intervention.

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.

Survival of the fattest: unexpected findings about hyperglycaemia and obesity in a population based study of 75-year-olds

OBJECTIVE

To study the relationship between body mass index (BMI) and mortality among 75-year-olds with and without diabetes mellitus type 2 (DM) or impaired fasting glucose (IFG).

DESIGN

Prospective population-based cohort study with a 10-year follow-up.

PARTICIPANTS

A random sample of 618 of the 1100 inhabitants born in 1922 and living in the city of Västerås in 1997 were invited to participate in a cardiovascular health survey; 70% of those invited agreed to participate (432 individuals: 210 men, 222 women).

OUTCOME MEASURES

All-cause and cardiovascular mortality.

RESULTS

163 of 432 (38%) participants died during the 10-year follow-up period. The prevalence of DM or IFG was 41% (35% among survivors, 48% among non-survivors). The prevalence of obesity/overweight/normal weight/underweight according to WHO definitions was 12/45/42/1% (14/43/42/1% among survivors, 9/47/42/2% among non-survivors). The hazard rate for death decreased by 10% for every kg/m(2) increase in BMI in individuals with DM/IFG (HR 0.91, 95% CI 0.86 to 0.97; p=0.003). After adjustment for sex, current smoking, diagnosed hypertension, diagnosed angina pectoris, previous myocardial infarction and previous stroke/transient ischaemic attack, the corresponding decrease in mortality was 9% (HR 0.92, 95% CI 0.86 to 0.99; p=0.017). These findings remained after exclusion of individuals with BMI<20 or those who died within 2-year follow-up. In individuals without DM/IFG, BMI had no effect on mortality (HR 1.01, 95% CI 0.95 to 1.07; p=0.811). The HR for BMI differed significantly between individuals with and without DM/IFG (p interaction=0.025). The increased all-cause mortality in individuals with DM/IFG in combination with lower BMI was driven by cardiovascular death.

CONCLUSION

High all-cause and cardiovascular mortality was associated with lower BMI in 75-year-olds with DM/IFG but not in those without DM/IFG. Further studies on the combined effect of obesity/overweight and DM/IFG are needed in order to assess the appropriateness of current guideline recommendations for weight reduction in older people with DM/IFG.

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.

Changes in waist circumference and mortality in middle-aged men and women

Background

Waist circumference (WC) adjusted for body mass index (BMI) is positively associated with mortality, but the association with changes in WC is less clear. We investigated the association between changes in WC and mortality in middle-aged men and women, and evaluated the influence from concurrent changes in BMI.

Methodology/Principal Findings

Data on 26,625 healthy men and women from the Danish Diet, Cancer and Health study was analyzed. WC and BMI were assessed in 1993–97 and in 1999–02. Information on mortality was obtained by linkage to the Danish central Person Register. Hazard ratios (HR) were estimated with Cox regression models. During 6.7 years of follow-up, 568 and 361 deaths occurred among men and women, respectively. Changes in WC were positively associated with mortality (HR per 5 cm for the sexes combined  = 1.09 (1.02∶1.16) with adjustment for covariates, baseline WC, BMI and changes in BMI), whereas changes in BMI were inversely associated with mortality (HR per kg/m2 for the sexes combined  = 0.91 (0.86, 0.97) with adjustment for covariates, baseline WC, BMI and changes in WC). Associations between changes in WC and mortality were not notably different in sub-groups stratified according to changes in BMI, baseline WC or when smokers or deaths occurring within the first years of follow-up were excluded.

Conclusions/Significance

Changes in WC were positively associated with mortality in healthy middle-aged men and women throughout the range of concurrent changes in BMI. These findings suggest a need for development of prevention and treatment strategies targeted against redistribution of fat mass towards the abdominal region.

Potential health benefits and medical cost savings from calorie, sodium, and saturated fat reductions in the American diet

PURPOSE

Model the potential national health benefits and medical savings from reduced daily intake of calories, sodium, and saturated fat among the U.S. adult population.

DESIGN

Simulation based on secondary data analysis; quantitative research. Measures include the prevalence of overweight/obesity, uncontrolled hypertension, elevated cholesterol, and related chronic conditions under various hypothetical dietary changes.

SETTING

United States.

SUBJECTS

Two hundred twenty-four million adults.

MEASURES

Findings come from a Nutrition Impact Model that combines information from national surveys, peer-reviewed studies, and government reports.

ANALYSIS

The simulation model predicts disease prevalence and medical expenditures under hypothetical dietary change scenarios.

RESULTS

We estimate that permanent 100-kcal reductions in daily intake would eliminate approximately 71.2 million cases of overweight/obesity and save $58 billion annually. Long-term sodium intake reductions of 400 mg/d in those with uncontrolled hypertension would eliminate about 1.5 million cases, saving $2.3 billion annually. Decreasing 5 g/d of saturated fat intake in those with elevated cholesterol would eliminate 3.9 million cases, saving $2.0 billion annually.

CONCLUSIONS

Modest to aggressive changes in diet can improve health and reduce annual national medical expenditures by $60 billion to $120 billion. One use of the model is to estimate the impact of dietary change related to setting public health priorities for dietary guidance. The findings here argue that emphasis on reduction in caloric intake should be the highest priority.

A review and meta-analysis of the effect of weight loss on all-cause mortality risk

Overweight and obesity are associated with increased morbidity and mortality, although the range of body weights that is optimal for health is controversial. It is less clear whether weight loss benefits longevity and hence whether weight reduction is justified as a prime goal for all individuals who are overweight (normally defined as BMI>25 kg/m2). The purpose of the present review was to examine the evidence base for recommending weight loss by diet and lifestyle change as a means of prolonging life. An electronic search identified twenty-six eligible prospective studies that monitored subsequent mortality risk following weight loss by lifestyle change, published up to 2008. Data were extracted and further analysed by meta-analysis, giving particular attention to the influence of confounders. Moderator variables such as reason for weight loss (intentional, unintentional), baseline health status (healthy, unhealthy), baseline BMI (normal, overweight, obese), method used to estimate weight loss (measured weight loss, reported weight loss) and whether models adjusted for physical activity (adjusted data, unadjusted data) were used to classify subgroups for separate analysis. Intentional weight loss per se had a neutral effect on all-cause mortality (relative risk (RR) 1·01; P = 0·89), while weight loss which was unintentional or ill-defined was associated with excess risk of 22 to 39 %. Intentional weight loss had a small benefit for individuals classified as unhealthy (with obesity-related risk factors) (RR 0·87 (95 % CI 0·77, 0·99); P = 0·028), especially unhealthy obese (RR 0·84 (95 % CI 0·73, 0·97); P = 0·018), but appeared to be associated with slightly increased mortality for healthy individuals (RR 1·11 (95 % CI 1·00, 1·22); P = 0·05), and for those who were overweight but not obese (RR 1·09 (95 % CI 1·02, 1·17); P = 0·008). There was no evidence for weight loss conferring either benefit or risk among healthy obese. In conclusion, the available evidence does not support solely advising overweight or obese individuals who are otherwise healthy to lose weight as a means of prolonging life. Other aspects of a healthy lifestyle, especially exercise and dietary quality, should be considered. However, well-designed intervention studies are needed clearly to disentangle the influence of physical activity, diet strategy and body composition, in order to define appropriate advice to those populations that might be expected to benefit.

The future of obesity reduction: beyond weight loss

Obesity increases the risk of morbidity and mortality and reduces quality of life independent of age, sex or ethnicity. Leading health authorities recommend weight loss as a primary treatment strategy for obesity reduction--weight loss goals range from 5% to 10% of initial body weight. Intentional weight loss in most adults is associated with a reduction in many of the health complications of obesity. Nonetheless, emerging evidence supports the notion that a lifestyle-modification program characterized by an increase in physical activity and a balanced diet can reduce obesity and the risk of obesity-related comorbid conditions despite minimal or no weight loss. The benefits of such an approach include appreciable reductions in abdominal obesity, visceral fat and cardiometabolic risk factors, and increases in both skeletal muscle mass and cardiorespiratory fitness. Individuals with obesity face a serious challenge if they are to attain even modest weight loss in today's obesogenic environment. Clinicians could encourage positive lifestyle changes in their patients by counseling them that obesity and its associated health risks can be reduced in response to an increase in physical activity with or without weight loss.