A population-based approach to define body-composition phenotypes

Body composition phenotypes and obesity paradox

PURPOSE OF REVIEW

The obesity paradox is a highly controversial concept that may be attributed to methodological limitations related to its identification. One of the primary concerns is the use of BMI to define obesity. This index does not differentiate lean versus adipose tissue compartments (i.e. body composition) confounding health consequences for morbidity and mortality, especially in clinical populations. This review will describe the past year's evidence on the obesity paradox phenomenon, primarily focusing on the role of abnormal body composition phenotypes in explaining the controversies observed in the literature.

RECENT FINDINGS

In spite of the substantial number of articles investigating the obesity paradox phenomenon, less than 10% used a direct measure of body composition and when included, it was not fully explored (only adipose tissue compartment evaluated). When lean tissue or muscle mass is taken into account, the general finding is that a high BMI has no protective effect in the presence of low muscle mass and that it is the latter that associates with poor prognosis.

SUMMARY

In view of the body composition variability of patients with identical BMI, it is unreasonable to rely solely on this index to identify obesity. The consequences of a potential insubstantial obesity paradox are mixed messages related to patient-related prognostication.

Body composition of children with cancer during treatment and in survivorship

BACKGROUND

Malnutrition as assessed with the use of body-composition measurements is a poorly understood short- and long-term complication of childhood cancer.

OBJECTIVES

We aimed to evaluate the body composition of 2 childhood cancer cohorts as follows: 1) children currently undergoing cancer treatment and 2) childhood cancer survivors. We also aimed to compare the prevalence of obesity and undernutrition between the cancer groups and investigate the impact of cancer type on body composition.

DESIGN

Eighty-two children during the treatment of cancer and 53 childhood cancer survivors were involved in the study. Height, weight, body cell mass, percentage of fat, fat mass index, and fat-free mass index were assessed. Subjects were compared with age- and sex-matched healthy controls.

RESULTS

The on-treatment group had a higher percentage of fat (P = 0.0001) and fat mass index (P = 0.0001) and a significantly lower body cell mass index (P = 0.0001) and fat-free mass index (P = 0.003) than did matched controls. The survivor group had a significantly higher percentage of fat (P = 0.03) and fat mass index (P = 0.04) and significantly lower body cell mass index (P = 0.0001) than did matched controls. The prevalence of undernutrition was high in both groups with 48% (95% CI: 36%, 60%) of the on-treatment group and 53% (95% CI: 40%, 66%) of the survivors considered undernourished. According to the percentage of fat cutoffs, significantly more on-treatment patients were obese (55%; 95% CI: 40%, 60%) than were survivors (26%; 95% CI: 14%, 38%) (P = 0.005). There were no statistically significant differences in body composition between cancer types in either the on-treatment or the survivor group.

CONCLUSIONS

Overnutrition and undernutrition are major concerns in the short and long term for children with cancer. Children treated for cancer have increased fat mass and decreased body cell mass, which are evident during treatment and in survivorship. This trial was registered at http://www.ANZCTR.org.au as ACTRN12614001279617 and ACTRN12614001269628.

Sarcopenic obesity and complex interventions with nutrition and exercise in community-dwelling older persons--a narrative review

One of the many threats to independent life is the age-related loss of muscle mass and muscle function commonly referred to as sarcopenia. Another important health risk in old age leading to functional decline is obesity. Obesity prevalence in older persons is increasing, and like sarcopenia, severe obesity has been consistently associated with several negative health outcomes, disabilities, falls, and mobility limitations. Both sarcopenia and obesity pose a health risk for older persons per se, but in combination, they synergistically increase the risk for negative health outcomes and an earlier onset of disability. This combination of sarcopenia and obesity is commonly referred to as sarcopenic obesity. The present narrative review reports the current knowledge on the effects of complex interventions containing nutrition and exercise interventions in community-dwelling older persons with sarcopenic obesity. To date, several complex interventions with different outcomes have been conducted and have shown promise in counteracting either sarcopenia or obesity, but only a few studies have addressed the complex syndrome of sarcopenic obesity. Strong evidence exists on exercise interventions in sarcopenia, especially on strength training, and for obese older persons, strength exercise in combination with a dietary weight loss intervention demonstrated positive effects on muscle function and body fat. The differences in study protocols and target populations make it impossible at the moment to extract data for a meta-analysis or give state-of-the-art recommendations based on reliable evidence. A conclusion that can be drawn from this narrative review is that more exercise programs containing strength and aerobic exercise in combination with dietary interventions including a supervised weight loss program and/or protein supplements should be conducted in order to investigate possible positive effects on sarcopenic obesity.

Rheumatoid cachexia and other nutritional alterations in rheumatologic diseases

The prevalence of nutritional alterations in rheumatologic diseases ranges from 4 to 95%, depending on the detection method used. Formerly described as the single term rheumatoid cachexia, nutritional alterations can currently be grouped and subdivided based on the physiopathological mechanisms involved: chronic disease-related inflammatory conditions (cachexia), malnutrition associated to acute malnutrition inflammatory conditions (protein-caloric malnutrition) and starvation-related malnutrition. Clinical manifestations of malnutrition associated to rheumatic diseases vary from the patient with low weight or overweight and obesity; with lean body mass depletion as well as functional repercussions, and impact of quality of life as a common denominator. Additionally, the associated increase in body fat mass increases the risk for cardiovascular morbidity. A multidisciplinary approach towards rheumatic diseases should include aspects oriented towards prevention, early identification, diagnosis and correction of nutritional alterations.

Antagonistic implications of sarcopenia and abdominal obesity on physical performance in COPD

Decreased physical performance due to loss of muscle mass (i.e. sarcopenia) is prevalent in ageing and appears more pronounced in chronic disease. A comprehensive profile of the sarcopenic phenotype in chronic obstructive pulmonary disease (COPD) is not yet available. The aim of the present study was to characterise prevalence, functional implications and predictive value of sarcopenia with or without abdominal obesity in Dutch COPD patients eligible for pulmonary rehabilitation.

505 COPD patients (aged 37–87 years; 57% male) underwent assessment of lung function, body composition and physical functioning, before entering pulmonary rehabilitation. Sarcopenia was assessed by appendicular skeletal muscle index (ASMI) and abdominal obesity by android/gynoid percentage fat mass (A/G%FM) using dual energy X-ray absorptiometry.

86.5% of patients were sarcopenic and showed lower physical functioning, while coexistent abdominal obesity (78.0%) resulted in higher physical functioning. Implications on endurance were less pronounced in women. The predictive value for physical functioning was higher for the “three-compartment” model (ASMI, bone mineral content and A/G%FM) than the “two-compartment” model (fat-free mass index and fat mass index) or “one-compartment” model (body mass index).

In patients eligible for pulmonary rehabilitation, sarcopenia is highly prevalent in all body mass index categories and associated with impaired strength, and in men also with decreased endurance. Abdominal obesity seems to have protective effects on physical functioning. ASMI is a better predictor for physical functioning than fat-free mass index.

Nutritional advances in patients with respiratory diseases

Nutritional issues are increasingly recognised in the course of respiratory diseases, from primary prevention to advanced disease care. During the 2014 ERS International Congress in Munich, Germany, the topic was addressed in a Clinical Year in Review session. This review highlights new insights in generic and disease-specific nutritional issues from recently published peer-reviewed articles. The clinical relevance of obesity was highlighted in primary and secondary prevention across all respiratory diseases. Radiographic imaging was explored for characterisation of metabolic phenotypes as an integrated part of diagnostic work-up. Muscle regenerative defects and the autophagy-lysosome pathway were identified as new leads for combatting muscle wasting.

Age-related changes in resting energy expenditure in normal weight, overweight and obese men and women

OBJECTIVES

Aging is associated with changes in resting energy expenditure (REE) and body composition. We investigated the association between age and changes in REE in men and women stratified by body mass index (BMI) categories (normal weight, overweight and obesity). We also examined whether the age-related decline in REE was explained by concomitant changes in body composition and lifestyle factors.

STUDY DESIGN

Cross-sectional.

MAIN OUTCOME MEASURES

3442 adult participants (age range: 18-81 y; men/women: 977/2465) were included. The BMI range was 18.5-60.2 kg/m(2). REE was measured by indirect calorimetry in fasting conditions and body composition by bioelectrical impedance. Regression models were used to evaluate age-related changes in REE in subjects stratified by sex and BMI. Models were adjusted for body composition (fat mass, fat free mass), smoking, disease count and physical activity.

RESULTS

In unadjusted models, the rate of decline in REE was highest in obese men (slope=-8.7±0.8 kcal/day/year) whereas the lowest rate of decline was observed in normal weight women (-2.9±0.3 kcal/day/year). Gender differences were observed for the age of onset of REE adaptive changes (i.e., not accounted by age related changes in body composition and lifestyle factors). In women, adaptive changes appeared to occur in middle-age (∼47 y) across all BMI groups whereas changes seemed to be delayed in obese men (∼54 y) compared to overweight (∼43 y) and normal weight (∼39 y) men.

CONCLUSIONS

Sex and BMI influenced the rate and degree of the age-related decline in REE. Critical age windows have been identified for the onset of putative mechanisms of energy adaptation. These findings require confirmation in prospective studies.

Obesity phenotypes in urban and rural Cameroonians: a cross-sectional study

BACKGROUND

Despite the increasing prevalence of diabetes and other health consequences of obesity, little is known on the metabolic profile across categories of body mass index (BMI) among African populations. We therefore assessed the prevalence and distribution of body size phenotypes among urban and rural Cameroonians.

METHODS

Adults (n = 1628; 41% rural dwellers) aged 24-74 years in 1994 provided data on BMI and metabolic health, defined on the basis of elevated levels of blood pressure (BP); triglycerides, fasting plasma glucose (FPG), and insulin resistance as assessed with homeostasis model assessment (HOMA). Cross-classification of BMI categories and metabolic status (healthy/unhealthy) created six groups. Metabolic measures include elevated blood pressure; elevated triglycerides (≥150 mg/dL or 1.69mmo/L), elevated fasting plasma glucose (≥100 mg/dl or 5.6 mmol/L or documented use of antidiabetic medications), and elevated homeostasis model assessment of insulin resistance value (HOMA-IR > 90(th) percentile).

RESULTS

A total of 25.2% of participants were overweight yet metabolically healthy (<1 abnormality) and 10.1% were obese yet metabolically healthy, whereas 1.4% were normal weight but metabolically abnormal (≥2 abnormalities). Proportion of rural dwellers with abnormal metabolic phenotype across normal-weight, overweight, obese categories were 2.9%, 0.8% and 0.3%, respectively; and 0 .3%, 2.2% and 2.6% among urban dwellers. Metabolically abnormal participants increased linearly across BMI categories (p < 0.001). BMI categories and metabolic status interacted to affect age, gender, BMI, FPG, triglycerides, and BP status distributions (all p < 0.04). Metabolic status and residence (rural vs. urban) interacted to influence the distribution across BMI categories of diastolic BP, BMI, waist circumference, fasting and 2-hour glucose, triglycerides, HOMA-IR, and prevalent diabetes (all p < 0.005), with differential occurrence of BMI categories and metabolic status among urban and rural participants.

CONCLUSIONS

Metabolic healthy obesity and obesity with a favorable cardiometabolic profile are not uncommon among Cameroonians, including among rural dwellers; but the latter group tended to have a better profile.

Clinical and economic outcomes of nutrition interventions across the continuum of care

Optimal nutrition across the continuum of care plays a key role in the short- and long-term clinical and economic outcomes of patients. Worldwide, an estimated one-quarter to one-half of patients admitted to hospitals each year are malnourished. Malnutrition can increase healthcare costs by delaying patient recovery and rehabilitation and increasing the risk of medical complications. Nutrition interventions have the potential to provide cost-effective preventive care and treatment measures. However, limited data exist on the economics and impact evaluations of these interventions. In this report, nutrition and health system researchers, clinicians, economists, and policymakers discuss emerging global research on nutrition health economics, the role of nutrition interventions across the continuum of care, and how nutrition can affect healthcare costs in the context of hospital malnutrition.

Lean tissue imaging: a new era for nutritional assessment and intervention

Body composition refers to the amount of fat and lean tissues in our body; it is a science that looks beyond a unit of body weight, accounting for the proportion of different tissues and its relationship to health. Although body weight and body mass index are well-known indexes of health status, most researchers agree that they are rather inaccurate measures, especially for elderly individuals and those patients with specific clinical conditions. The emerging use of imaging techniques such as dual energy x-ray absorptiometry, computerized tomography, magnetic resonance imaging, and ultrasound imaging in the clinical setting have highlighted the importance of lean soft tissue (LST) as an independent predictor of morbidity and mortality. It is clear from emerging studies that body composition health will be vital in treatment decisions, prognostic outcomes, and quality of life in several nonclinical and clinical states. This review explores the methodologies and the emerging value of imaging techniques in the assessment of body composition, focusing on the value of LST to predict nutrition status.