Aging, physical activity and height-normalized body composition parameters

Cardiac MRI shows an association of lower cardiorespiratory fitness with decreased myocardial mass and higher cardiac stiffness in the general population - The Sedentary's Heart

BACKGROUND

The heart has the capacity to adapt to different demands. The pathophysiological mechanisms involved with sedentarism are not fundamentally the opposite of those related with physical activity and regular exercise. We investigated the impact of lower cardiorespiratory fitness (CRF) on heart's plasticity and function in a population-based setting.

METHODS

We used data from 1165 participants (539 women; 46.3%) aged 21-81 years from two independent cohorts of the Study of Health in Pomerania (SHIP-2 and SHIP-TREND-0). We analyzed the cross-sectional associations of peak oxygen uptake (VO_2peak), determined by symptom-limited cardiopulmonary exercise testing, with structural and functional left ventricular (LV) and left atrial (LA) parameters determined by magnetic resonance imaging (MRI) using multivariable- adjusted linear regression models.

RESULTS

A 1 L/min lower VO_2peak was associated with a 10.5 g (95% confidence interval: 8.00 to 12.9; p < 0.001) lower LV mass, a 14.8 mL (10.9 to 18.6; p < 0.001) lower LV end-diastolic volume, a 0.29 mm (0.19 to 0.40; p < 0.001) lower LV wall-thickness, a 8.85 mL/beat (6.53 to 11.2; p < 0.001) lower LV stroke volume, a 0.42 L/min (0.25 to 0.60; p < 0.001) lower LV cardiac output and a 7.51 mL (3.88 to 11.1; p < 0.001) lower LA end-diastolic volume. Moreover, there were no associations with a concentric or eccentric remodeling and LV and LA ejection fraction.

CONCLUSIONS

Lower CRF was associated with a smaller heart, LV wall-thickness and mass, LV and LA stroke volume and cardiac output. Conversely, there was no association with LA and LV ejection fraction. Our cross-sectional observations are consistent with cardiac adaptations reflecting reduced volume loading demands of a sedentary lifestyle - "the sedentary's heart".

Benchmarking the Discriminatory Performance of Body Mass Index and Body Fat for Obesity Detection in Patients Treated by Intragastric Balloon

INTRODUCTION/PURPOSE

The accuracy of body mass index (BMI) in detecting obesity in patients treated by intragastric balloon (IGB) remains still speculative. We aimed to determine the discriminatory performance of BMI as an estimate of excess body fat (%BF) in an IGB-treated population.

MATERIAL AND METHODS

Retrospective analysis of prospectively collected data of 476 patients who completed the 6-month IGB treatment period and were subjected to body composition analysis. We evaluated the relationship between BMI and %BF or lean mass and the diagnostic performance of BMI ≥ 30 kg/m² for adipose tissue detection, stratified by age (< 40 and ≥ 40 years) and gender. Moreover, we identified anthropometric and body composition parameters serving as predictors of obesity according to %BF-based criteria (> 25% in men or > 35% in women).

RESULTS

Gender emerged as an effect modifier in the quadratic polynomial relationship between BMI and %BF (R² = 0.849 for men, R² = 0.715 for women), while BMI was linearly associated with %BF in both age groups (R² = 0.435 for men, R² = 0.474 for women). BMI was strongly correlated with both %BF (r = 0.67) and lean mass (r = - 0.65). The overall area under the ROC curve for BMI ≥ 30 kg/m² to detect %BF was 0.87 (95%CI 0.85-0.90). A regression model including lean mass, total body water, age, BMI, and female gender explained 0.970 of the variance in %BF.

CONCLUSION

The discriminatory performance of BMI as an estimate of excess body fat is enhanced by the implementation of gender- and age-specific BMI thresholds for defining obesity, in IGB-treated patients.

Prospective study on sedentary behaviour patterns and changes in body composition parameters in older women: A compositional and isotemporal substitution analysis

BACKGROUND & AIMS

The aims of this study were to examine the prospective compositional associations between sedentary behaviour (SB) patterns and longitudinal changes in body composition parameters, and to use compositional isotemporal substitution modelling to analyse the longitudinal changes in body composition parameters associated with time reallocation from SB to physical activity (PA) in older women.

METHODS

The study included women aged 60 years and older (n = 182) with valid data at baseline and at the subsequent 7-year follow-up. For both time points, the ActiGraph GT1M accelerometer was used for SB and PA assessments and multi-frequency bioimpedance analysis was used to assess the body composition parameters related to adiposity and muscle mass. Compositional regression models were used to analyse the associations between proportion of time spent in sedentary bouts of different duration and longitudinal changes in body composition parameters. A compositional isotemporal substitution model was created to estimate the differences in body composition parameters associated with one-to-one time reallocations between baseline SB and PA.

RESULTS

A significant increase in fat mass index (β_ilr1 = 0.61, 95% confidence interval [CI]: 0.18, 1.04) and visceral adipose tissue (β_ilr1 = 6.01, 95% CI: 1.52, 10.5) was associated with a higher baseline proportion of time spent in long sedentary bouts (i.e. sedentary bout of ≥30 min). Reallocating 1 h/week and 3.5 h/week from the time spent in long sedentary bouts in favour of light PA was associated with a significant decrease in fat mass index by 0.78% (95% CI: 0.24, 1.32) and 3.13% (95% CI: 0.97, 5.29), respectively. No association was found for indicators of muscle mass.

CONCLUSIONS

This study suggests that long-term adiposity status could be improved by increasing the proportion of time spent in light PA at the expense of time spent in prolonged SB. This finding may help in designing more effective and feasible interventions for the maintenance of healthy body composition in advanced age.

Fat-free mass and glucose homeostasis: is greater fat-free mass an independent predictor of insulin resistance?

BACKGROUND

A greater fat-free mass (FFM) is purported to be associated with protective effects on insulin resistance (IR). However, recent studies suggested negative associations between FFM and IR.

OBJECTIVES

(1) To explore the direction of the association between FFM and IR in a large heterogeneous sample after controlling for confounding factors. (2) To determine cut off values of FFM associated with an increased risk of IR.

METHODS

Outcome variables were measured in 7044 individuals (48.6% women, 20-79 years; NHANES, 1999-2006): body composition [fat mass (FM), FFM and appendicular FFM (aFFM); DXA], FFM index [FFMI: FFM/height (kg/m²)], appendicular FFMI [aFFM/height (kg/m²)] and insulin resistance (HOMA-IR). Multivariate regression analyses were performed to determine the independent predictors of HOMA-IR in younger (20-49 years) and older (50-79 years) men and women. ROC analyses were used to determine FFM cut-offs to identify a higher risk of insulin resistance (HOMA-IR > 75th percentile).

RESULTS

aFFMI was an independent predictor of IR in younger (men: β = 0.21; women: β = 0.31; all p ≤ 0.001) and older (men: β = 0.11; women: β = 0.37; all p ≤ 0.001) individuals. Thresholds for aFFMI at which the risk of IR was significantly increased were 8.96 and 8.39 kg/m² in younger and older men, and 7.22 and 6.64 kg/m² in younger and older women, respectively.

CONCLUSION

Independently of age, a greater aFFMI was an independent predictor of IR. These results suggest revisiting how we envision the link between FFM and IR and explore potential mechanisms.

Associations among Geriatric Nutrition Risk Index, bone mineral density, body composition and handgrip strength in patients receiving hemodialysis

OBJECTIVES

Malnutrition occurs as a complication of hemodialysis (HD) and has been identified as a risk factor for osteoporosis, sarcopenia, and low physical performance. The aim of this study was to assess the associations among nutrition, bone mineral density (BMD), body composition, and handgrip strength (HGS) in patients receiving HD.

METHODS

We enrolled 164 patients receiving HD who have undergone the dual energy x-ray absorptiometry (DXA) examination, categorized according to baseline Geriatric Nutritional Risk Index (GNRI) values calculated by serum albumin levels and body weight index. GNRI was used to evaluate nutritional status, and DXA to investigate BMD and body composition. Additionally, HGS test was performed. Multiple stepwise linear regression analysis was used to identify the factors associated with BMD, T-score, and HGS.

RESULTS

Compared with patients with tertile 1 of GNRI, those with tertile 3 of GNRI tend to have higher lumbar spine BMD and T-score, higher femoral neck BMD, higher total hip BMD, higher left distal mid-third radius BMD and T-score, higher fat mass index, higher android-to-gynoid ratio, higher lean mass index, and higher HGS. An increase in GNRI tertile was associated with an increase of BMD and a decrease of osteoporosis prevalence. The GNRI was positively correlated with BMD and T-score, body composition, and HGS. Low lean mass index and high parathyroid hormone were significantly associated with low BMD and T-score. Additionally, high GNRI and high left distal mid-third radius BMD were significantly associated with high HGS.

CONCLUSIONS

The present study demonstrated that good nutrition, indicated as high GNRI, resulted in higher BMD and T-score, lean mass index, and HGS in patients receiving HD. Using GNRI to evaluate nutritional status and using DXA to investigate BMD and body composition in patients receiving HD is important to bone health and physical performance.

Effects of a 6-month caloric restriction induced-weight loss program in obese postmenopausal women with and without the metabolic syndrome: a MONET study

OBJECTIVE

To compare the effects of a caloric restriction (CR) on body composition, lipid profile, and glucose homeostasis in obese postmenopausal women with and without metabolic syndrome (MetS).

METHODS

Secondary analyses were performed on 73 inactive obese postmenopausal women (age 57.7 ± 4.8 years; body mass index 32.4 ± 4.6 kg/m) who participated in the 6-month CR arm of a study of the Montreal-Ottawa New Emerging Team. The harmonized MetS definition was used to categorize participants with MetS (n = 20, 27.39%) and without MetS (n = 53, 72.61%). Variables of interest were: body composition (dual-energy X-ray absorptiometry), body fat distribution (computed tomography scan), glucose homeostasis at fasting state and during a euglycemic/hyperinsulinemic clamp, fasting lipids, and resting blood pressure.

RESULTS

By design, the MetS group had a worse cardiometabolic profile, whereas both groups were comparable for age. Fifty-five participants out of 73 displayed no change in MetS status after the intervention. Twelve participants out of 20 (or 60.0%) in the MetS group had no more MetS after weight loss (P = NS), whereas 6 participants out of 53 (or 11.3%) in the other group developed the MetS after the intervention (P = NS). Overall, indices of body composition and body fat distribution improved significantly and similarly in both groups (P between 0.03 and 0.0001). Furthermore, with the exception of triglyceride levels and triglycerides/high-density lipoprotein cholesterol ratio, which decrease significantly more in the MetS group (P ≤ 0.05), no difference was observed between groups for the other variables of the cardiometabolic profile.

CONCLUSIONS

Despite no overall significant effects on MetS, heteregeneous results were obtained in response to weight loss in the present study, with some improving the MetS, whereas other displaying deteriorations. Further studies are needed to identify factors and phenotypes associated with positive and negative cardiometabolic responses to CR intervention.

An overview of assessment methodology for obesity-related variables in infants at risk

BACKGROUND

The first 2 years of a child's life are a particularly critical time period for obesity prevention.

AIM

An increasing amount of research across the world is aimed at understanding factors that impact early childhood obesity and developing interventions that target these factors effectively. With this growing interest, new and interdisciplinary research teams are developing to meet this research need. Due to rapid growth velocity during this phase of the lifespan, typical assessments used in older populations may not be valid or applicable in infants, and investigators need to be aware of the pros and cons of specific methodological strategies.

METHODS

This paper provides an overview of methodology available to assess obesity-related factors in the areas of anthropometry and body composition, nutrient intake, and energy expenditure in infants aged 0-2 years.

RESULTS

Gold standard measures for body composition, such as dual-energy X-ray absorptiometry (DXA) or other imaging techniques, are costly, require highly trained personnel, and are limited for research application. Nutrient intake methodology primarily includes surveys and questionnaires completed via parent proxy report. In terms of energy expenditure, methods of calorimetry are expensive and may not differentiate between different activities. Questionnaires or physical activity sensors offer another way of energy expenditure assessment. However, questionnaires have a certain recall bias, while the sensors require further validation.

CONCLUSIONS

Overall, in addition to understanding the pros and cons of each assessment tool, researchers should take into consideration the experience of the interdisciplinary team of investigators, as well as the cost and availability of measures at their institution.

Fat-free mass depletion in patients with COPD in Brazil: development of a new cutoff point and its relation with mortality and extrapulmonary manifestations

BACKGROUND/OBJECTIVES

None of the cutoff points for fat-free mass index (FFMI) were tested for the Brazilian population, and it is unknown whether the available ones are able to discriminate extrapulmonary disease manifestations. This cross-sectional study aims to develop and validate a cutoff point for FFM depletion based on Brazilian patients with chronic obstructive pulmonary disease (COPD) and to verify its association and of previously published cutoffs with extrapulmonary manifestations.

SUBJECTS/METHODS

A new cutoff point was obtained from the best FFMI value for discrimination of preserved exercise capacity in a sample of patients (n=57). The discriminative capacity was assessed in another sample (n=96). The new cutoff point and other previously published ones were tested to discriminate low exercise capacity, physical inactivity, sedentary lifestyle and low quality of life. A receiver operation characteristics curve with area under the curve (AUC) value was plotted and each cutoff points' discriminative capacity was calculated. Cox regression and Kaplan-Meier method assessed the association between the cutoff points and mortality.

RESULTS

The new cutoff points for FFMI were 14.65 kg/m² for women (AUC=0.744; sensitivity (Se)=0.88; specificity (Sp)=0.60) and 20.35 kg/m² for men (AUC=0.565; Se=0.36; Sp=0.81). The new cutoffs were the best to discriminate poor exercise capacity assessed by walked distance in % predicted and quality of life. Only the new cutoff point was associated with mortality (HR=2.123; 95% CI: 1.03-4.33, P=0.039, log rank P=0.035).

CONCLUSIONS

Only the new cutoff point was associated with all-cause mortality, and it had the highest discriminating capacity for exercise capacity and quality of life in Brazilian patients with COPD.

Body Composition Tools for Assessment of Adult Malnutrition at the Bedside: A Tutorial on Research Considerations and Clinical Applications

Because of the key role played by the body's lean tissue reserves (of which skeletal muscle is a major component) in the response to injury and illness, its maintenance is of central importance to nutrition status. With the recent development of the Academy of Nutrition and Dietetics/American Society for Parenteral and Enteral Nutrition diagnostic framework for malnutrition, the loss of muscle mass has been recognized as one of the defining criteria. Objective methods to evaluate muscle loss in individuals with acute and chronic illness are needed. Bioimpedance and ultrasound techniques are currently the best options for the clinical setting; however, additional research is needed to investigate how best to optimize measurements and minimize error and to establish if these techniques (and which specific approaches) can uniquely contribute to the assessment of malnutrition, beyond more subjective evaluation methods. In this tutorial, key concepts and statistical methods used in the validation of bedside methods to assess lean tissue compartments are discussed. Body composition assessment methods that are most widely available for practice and research in the clinical setting are presented, and clinical cases are used to illustrate how the clinician might use bioimpedance and/or ultrasound as a tool to assess nutrition status at the bedside. Future research needs regarding malnutrition assessment are identified.

Nutritional influences on age-related skeletal muscle loss

Age-related muscle loss impacts on whole-body metabolism and leads to frailty and sarcopenia, which are risk factors for fractures and mortality. Although nutrients are integral to muscle metabolism the relationship between nutrition and muscle loss has only been extensively investigated for protein and amino acids. The objective of the present paper is to describe other aspects of nutrition and their association with skeletal muscle mass. Mechanisms for muscle loss relate to imbalance in protein turnover with a number of anabolic pathways of which the mechanistic TOR pathway and the IGF-1–Akt–FoxO pathways are the most characterised. In terms of catabolism the ubiquitin proteasome system, apoptosis, autophagy, inflammation, oxidation and insulin resistance are among the major mechanisms proposed. The limited research associating vitamin D, alcohol, dietary acid–base load, dietary fat and anti-oxidant nutrients with age-related muscle loss is described. Vitamin D may be protective for muscle loss; a more alkalinogenic diet and diets higher in the anti-oxidant nutrients vitamin C and vitamin E may also prevent muscle loss. Although present recommendations for prevention of sarcopenia focus on protein, and to some extent on vitamin D, other aspects of the diet including fruits and vegetables should be considered. Clearly, more research into other aspects of nutrition and their role in prevention of muscle loss is required.

Is there a skeletal muscle mass threshold associated with the deterioration of insulin sensitivity in sedentary lean to obese postmenopausal women?

AIM

The purpose of this study was to determine an optimal cut-off point of skeletal muscle mass, using appendicular lean body mass (LBM) index, that identifies at risk individuals with deteriorated insulin sensitivity, using an established quantitative insulin sensitivity index (QUICKI) cut-off.

METHODS

We performed a cross-sectional analysis in 231 lean and obese (BMI: 18.7-51.0 kg/m(2)) menopausal women. Fasting plasma glucose and insulin were obtained to calculate QUICKI as an index of insulin sensitivity. Skeletal muscle mass was measured as appendicular LBM by DXA and expressed as appendicular LBM index [appendicular LBM (kg)/height (m(2))]. Cut-offs were determined using receiver operating characteristic (ROC) curve analyses.

RESULTS

The best cut-off value for skeletal muscle mass index to identify menopausal women with reduced insulin sensitivity was 7.025 kg/m(2) which had a sensitivity of 69.5% and specificity of 58.2%.

CONCLUSION

Our results suggest that sedentary postmenopausal women with an appendicular skeletal muscle mass index above 7.025 kg/m(2) may be at greater risk of insulin resistance. Prospective studies are needed to validate our result.

Total and regional relationship between lean and fat mass with increasing adiposity--impact for the diagnosis of sarcopenic obesity

BACKGROUND/OBJECTIVE

Besides the effect of age used to define sarcopenia, there is need to understand the impact of adiposity on the relationship between lean (fat-free mass, FFM) and fat mass (FM) in order to diagnose sarcopenic obese phenotypes. More importantly, the regional distribution of skeletal muscle (SM) to adipose tissue (AT) or the composition of FFM (that is, SM proportion of lean mass) may also depend on adiposity.

SUBJECTS/METHODS

In a large database (n=1737) of healthy males and females (age 11-84 years, BMI 13.5-52.5 kg/m(2)) we investigated changes in the relationship between FFM and FM (normalized by height as fat-free mass index and fat mass index: FFMI and FMI, kg/m(2) assessed by densitometry) with increasing adiposity and age. In a subgroup (n=263) we analyzed the relationship between regional SM and (i) AT (by magnetic resonance imaging) or (ii) lean soft tissue (by dual X-ray absorptiometry) with increasing adiposity.

RESULTS

The relationship between lean and FM was influenced by adiposity, age and gender. With increasing adiposity, SM/AT declined faster at the trunk in men and at the extremities in women. The contribution of appendicular SM to lean soft tissue of arms and legs tended to decrease at a higher adiposity in both genders (FMI >6.97 kg/m(2) in women; FMI>7.77 kg/m(2) in men).

CONCLUSION

Besides age and gender, adiposity and body region should be considered when evaluating the normal relationship between lean and FM, SM/FFM and SM/AT.

Upper-Body Resistance Training and Self-Efficacy Enhancement in COPD

PURPOSE

Loss of skeletal muscle strength is commonly seen with chronic obstructive pulmonary disease (COPD). The study aim was to determine the effects of comprehensive upper-body resistance training (8 different lifts) and a self-efficacy enhancing intervention in COPD with respect to muscle strength, symptoms, functional status and exercise adherence.

METHODS

This randomized trial had 3 groups: upper-body resistance training with an intervention to enhance self-efficacy (UBR + SE), upper-body resistance training and health education (UBR + HE), gentle chair exercises and health education (CE + HE). Subjects performed 16 weeks of supervised training, then 12 months of long-term maintenance at home. Outcomes were: muscle strength, dyspnea, functional status, self-efficacy, and adherence.

RESULTS

Sixty-four subjects completed 16 wks of training: age 71 ± 8 yr, fat-free mass index 19 ± 3 kg/m2, forced expiratory volume in one second 58 ± 18 percent predicted. The UBR + SE intervention produced a 46% increase in strength compared to a 36% increase in the UBR + HE group (P = 0.054). The combined UBR + SE and UBR + HE groups produced a 41% increase in strength compared to an 11% increase in the CE+HE (P < 0.001). The combined UBR groups also demonstrated increases in lean arm mass (P = 0.003) and a trend toward decreased dyspnea (P = 0.053). There were no group differences in attrition, attendance and training progression. Fifty subjects completed long-term maintenance and the UBR + SE and UBR + HE groups retained some gains in muscle strength, 24% and 21% respectively, and the CE + HE group lost 3% of muscle strength from baseline.

CONCLUSION

The study provides strong evidence that comprehensive resistance training increased strength and lean arm mass and that strength can be partially maintained through a simple home program using hand weights. It provides limited evidence that upper-body resistance training improved dyspnea and that the exercise-specific self-efficacy enhancing intervention was beneficial.

The frailty syndrome: a comprehensive review

The frailty syndrome is defined as unintentional weight and muscle loss, exhaustion, and declines in grip strength, gait speed, and activity. Evidence with respect to the clinical definition, epidemiology, mechanisms, interactions, assessment, prevention, and treatment of frailty in the older adult is reviewed.

Socio-demographic and leisure activity determinants of physical activity of working warsaw residents aged 60 to 69 years

The purpose of the study was to assess factors determining physical activity in persons at the age of 60–69 years in an urban area. The study included 262 working residents of Warsaw at the initial period of old age. The study utilized a questionnaire consisting of two parts. The first part concerned recreational and touristic activities in the previous year. The second is a Polish version of IPAQ, assessing the respondents’ level of activity throughout the past week. Based on IPAQ results, the respondents were divided into physically active and inactive ones. The active group included people meeting moderate to vigorous physical activity, whereas the inactive group included people who took up no physical activity at all or those with a low physical activity level. The relations between taking up physical activity and the variables characterizing the demographic structure as well as touristic and recreational activity of the respondents were assessed with the use of a log-linear analysis. Out of the variables taken into account, age, education and participation in physical recreation proved to be significant factors in taking up activity by the elderly. The odds ratios computed for the analyzed variables indicate that the risk of being inactive increases over two times after exceeding 65 years of age; a risk of similar magnitude was also observed in case of less educated populations. Regular participation in physical recreation provides a four-times increase in the chances to achieve levels of physical activity sufficient to remain healthy.

Body mass index in a large cohort of patients assigned to age decades between <20 and ≥80 years: relationship with cardiovascular morbidity and medication

OBJECTIVE

There is an ongoing debate about the relationship between obesity and morbidity in the elderly, the clinical relevance of overweight and obesity in older patients and the need or harms of treatment. The main purpose of our study was to investigate whether a higher BMI is associated with a worse cardiovascular risk in all age groups, especially in the older ones.

SUBJECTS AND DESIGN

We performed a retrospective evaluation of clinical data from 3926 patients who visited a medical outdoor center for diagnostic and/or therapeutic interventions in the period from January 1995 to July 2010. Patients were assigned to eight age groups of one decade from <20 years to ≥80 years.

RESULTS

The Body Mass Index (BMI) of our patients showed a continuous increase with increasing age with peak values in the age decade 61-70 years (26.29 ±4.42 kg/m2). This was paralleled by an increase in cardiovascular events and need for continuous medication, demonstrating peak values in the age decade 61-70 years (22.3% in the female and 24.7% in the male group). In all age decades up to 80 years the BMI values were higher in patients with events compared to those without it. multivariable linear regression analysis - including confounding variables (blood pressure, fasting glucose, HDL-cholesterol, triglycerides, physical activity, smoking) - revealed for all age groups a strong positive relation of BMI and a negative relation of fat free mass (FFM) to the probability for a cardiovascular event and need for medication.

CONCLUSION

In all age groups, the percentage of cardiovascular events was directly correlated with the BMI. Having in mind the transition to an aging society, therapeutic and preventive strategies should, therefore, include weight management strategies also for the elderly.

Effect of age on the association between body fat percentage and maximal walking speed

OBJECTIVE

To study the effect of age on the association between body fat percentage and maximal walking speed in older people.

DESIGN AND PARTICIPANTS

Cross-sectional analysis of data collected in the Finnish population-based Health 2000 Survey involving 916 men and 1 222 women aged 55 years and older with complete data on body composition and a walking speed test.

METHODS

Body fat percentage was assessed using bioelectrical impedance analysis and maximal walking speed based on a timed walking test over a distance of 6.1 meters. Linear regression models were used to study the effect of age on association between body fat percentage and maximal walking speed.

RESULTS

The association between body fat percentage quartiles and maximal walking speed differed significantly between persons of different ages (p for age interaction = 0.027). In the age-stratified analyses, the association between body fat percentage and maximal walking speed remained significant among 60-69-year olds and 70-79-year-olds, but disappeared among 55-59-year-olds and 80-year and older after adjustment for potential covariates. Body fat percentage explained 11% of the variation in maximal walking speed among 55-59-year-olds, 21% among 60-69-year-olds, 17% among 70-79-year-olds and 11% among 80-year and older.

CONCLUSION

Association between body fat percentage and maximal walking speed was strongest between the ages of 60 and 79 years. The results suggest that the effects of excess body fatness are especially harmful for physical functioning among adults in their sixties and seventies and they could benefit from interventions.

Combined effects of chronic alcohol consumption and physical activity on bone health: study in a rat model

Chronic alcohol consumption may be deleterious for bone tissue depending on the amount of ethanol consumed, whereas physical activity has positive effects on bone. This study was designed to analyze the effects of moderate alcohol consumption on bone in trained rats. 48 male Wistar rats were divided into four groups: control (C), alcohol (A), exercise (E) and alcohol + exercise (AE). A and AE groups drank a solution composed of water and ethanol. E and AE groups were trained for 2 months (treadmill: 40 min/day, 5 times/week). Body composition and bone mineral density (BMD) were assessed by dual X-ray absorptiometry and microarchitectural parameters using micro-computed tomography. Serum osteocalcin and CTx were determined by ELISA assays. The body weight and lean mass gain were lower in group A, while the fat mass gain was lower in exercised groups. BMD and BMC were higher with alcohol after body weight adjustment. Trabecular thickness was significantly higher in AE and A groups compared to C and E; cross-sectional area was larger in A and C groups compared to AE and E. CTx levels were higher in A compared to C and in AE and E versus C and A. Osteocalcin levels were significantly greater in AE and E groups versus C and A. In conclusion, the light to moderate alcohol consumption over a short period increased the trabecular thickness, BMC and BMD in A and AE groups. However, we observed alterations in bone remodeling and body composition with alcohol, at the end of the protocol, which did not appear when alcohol was combined to exercise.

Lean mass predicts asthma better than fat mass among females

The obesity phenotype associated with asthma is not known. Our objective was to define the relative contribution of various distributions of fat and lean mass to asthma prevalence. Data were obtained from 2,525 participants (including 1,422 females) who underwent dual-energy X-ray absorptiometry (DEXA) at the year 20 examination in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. Total, truncal, arm and leg distributions of fat and lean mass were adjusted to the person's height. Self-reported asthma was the outcome. Asthma among females was associated with greater total fat mass, arm fat mass, total lean mass, truncal lean mass and arm lean mass. Among males, none of these mass measures were significantly associated with asthma. Among females, the association with asthma was stronger for total lean mass than for total fat mass. Further, among various regional distributions of lean and fat mass in females, truncal lean mass was the strongest predictor. Total lean mass is more strongly associated with asthma than total fat mass among females. These findings are contrary to the popular perception that excess physiological fat drives the obesity-asthma association. Rather, we hypothesise that ectopic fat within the "lean" tissues drives this association among females.

Comparison of body composition, handgrip strength, functional capacity, and physical activity in elderly Koreans and Korean immigrants

Immigration to a foreign country has a significant impact on a person's health status and health management behavior. The purpose of this pilot study was to examine body composition (body mass index and muscle area of the mid-upper arm and mid-calf), handgrip strength, functional capacity, and physical activity in elderly Koreans and Korean immigrants. In this cross-sectional study, a convenience sample of 87 elderly Korean immigrants and 294 elderly Koreans were recruited from senior centers and senior apartments in the United States and Korea. Compared with elderly Koreans, elderly Korean immigrants had higher mid-calf muscle area (p = 0.06), handgrip strength (p = 0.01), and functional capacity (p = 0.01) and less physical activity (p < 0.01). Older men were more physically active and had more muscle areas, greater handgrip strength, and better functional capacity than older women, whereas older women had higher BMI scores than older men. This study provides motives for the development of health promotion intervention studies (e.g., culturally relevant exercise programs incorporating strength training). Future studies could identify culturally relevant strategies to promote physical activity in elderly Korean immigrants and especially elderly Korean women in both groups.

Muscle forces or gravity: what predominates mechanical loading on bone?

Most mechanical forces acting on the skeleton are generated either through impact with the ground (i.e., gravitational loading) or through muscle contractions (i.e., muscle loading). If one of these conduits for activating mechanotransduction in bone is more effective than the other with respect to developing or maintaining bone strength, this would have important clinical implications for prescribing physical activity for the prevention or treatment of osteoporosis. This section of the symposium considered whether there is evidence from studies of humans that the effectiveness of physical activity to preserve bone health is dependent on whether the activities stimulate the skeleton primarily through gravitational or muscle loading. Conclusive evidence is lacking, but several lines of research suggest that physical activities that involve impact forces, and therefore generate both gravitation and muscle loading, are most likely to have beneficial effects on bone metabolism and reduce fracture risk.

Obesity and inflammation: the effects of weight loss

Following the discovery of TNF-α and leptin as secretory products of adipocytes in the early 1990s, subsequent obesity research focused on the new functional role of adipose tissue, as an active endocrine organ. Many more inflammatory peptides have been linked to adiposity, which ultimately characterised obesity as a state of low-grade systemic inflammation, or ‘metaflammation’ which may link obesity to its co-morbidities. The aim of the present review is to examine the effects of weight loss on inflammation in overweight and obese, but otherwise healthy, populations. Studies were broadly classified into four types (diet, physical activity, diet and physical activity combined, and surgical interventions) and discussed according to the method used to induce weight loss. All studies measured at least one obesity-related inflammatory marker (ORIM). The overall finding from the present review is that weight loss does improve inflammation in terms of both the inflammatory (C-reactive protein, TNF-α, IL-6 and leptin) and anti-inflammatory (adiponectin) ORIM. Within this, the greatest improvements in ORIM are observed in studies achieving a weight loss of at least 10 %. However, a number of methodological issues have been identified as potential limitations within the literature including the sex and age of subjects, sample size, study duration and the assessment of body composition. In conclusion, although a period of weight loss per se is capable of reversing the unfavourable inflammatory profile evident in the obese state, further studies are required to determine the time needed, in which a reduced weight is maintained, in order to benefit from improved inflammatory status long term.

Aging and induced senescence as factors in the pathogenesis of lung emphysema

Classically, the development of emphysema in chronic obstructive pulmonary disease is believed to involve inflammation induced by cigarette smoke and leukocyte activation, including oxidant-antioxidant and protease-antiprotease imbalances. While there is substantial evidence for this, additional aspects have been suggested by a number of clinical and experimental observations. Smokers exhibit signs of premature aging, particularly obvious in the skin. The link between aging and chronic disease is well-known, e.g., for the brain and musculoskeletal or cardiovascular system, as well as the clinical link between malnutrition and emphysema, and the experimental link to caloric restriction. Interestingly, this intervention also increases lifespan, in parallel with alterations in metabolism, oxidant burden and endocrine signaling. Of special interest is the observation that, even in the absence of an inflammatory environment, lung fibroblasts from patients with emphysema show persistent alterations, possibly based on epigenetic mechanisms. The importance of these mechanisms for cellular reprogramming and response patterns, individual risk profile and therapeutic options is becoming increasingly recognized. The same applies to cellular senescence. Recent findings from patients and experimental models open novel views into the arena of gene-environment interactions, including the role of systemic alterations, cellular stress, telomeres, CDK inhibitors such as p16, p21, pRb, PI3K, mTOR, FOXO transcription factors, histone modifications, and sirtuins. This article aims to outline this emerging picture and to stimulate the identification of challenging questions. Such insights also bear implications for the long-term course of the disease in relation to existing or future therapies and the exploration of potential lung regeneration.

Contribution of the lean body mass to insulin resistance in postmenopausal women with visceral obesity: a Monet study

Some insulin-resistant obese postmenopausal (PM) women are characterized by an android body fat distribution type and higher levels of lean body mass (LBM) compared to insulin-sensitive obese PM women. This study investigates the independent contribution of LBM to the detrimental effect of visceral fat (VF) levels on the metabolic profile. One hundred and three PM women (age: 58.0+/-4.9 years) were studied and categorized in four groups on the basis of their VF (higher vs. lower) and lean BMI (LBMI=LBM (kg)/height (m2); higher vs. lower). Measures included: fasting lipids, glucose homeostasis (by euglycemic/hyperinsulinemic clamp technique and 2-h oral glucose tolerance test (OGTT)), C-reactive protein (CRP) levels, fat distribution (by computed tomography (CT) scan), and body composition (by dual-energy X-ray absorptiometry). Women in the higher VF/higher LBMI group had lower glucose disposal and higher plasma insulin levels compared to the other groups. They also had higher plasma CRP levels than the women in the lower VF/lower LBMI group. VF was independently associated with insulin levels, measures of glucose disposal, and CRP levels (P<0.05). LBMI was also independently associated with insulin levels, glucose disposal, and CRP levels (P<0.05). Finally, significant interactions were observed between LBMI and VF levels for insulin levels during the OGTT and measures of glucose disposal (P<0.05). In conclusion, VF and LBMI are both independently associated with alterations in glucose homeostasis and CRP levels. The contribution of VF to insulin resistance seems to be exacerbated by increased LBM in PM women.

Association between walking distance and percentiles of body mass index in older and younger men

OBJECTIVE

To assess the association of weekly walking distance to body weight and waist circumference in elderly (age > or =75 years), senior (55< or = age <75 years), middle-aged (35< or = age <55 years), and younger men (18< or = age <35 years old).

DESIGN

Cross-sectional analyses of baseline questionnaires from 7082 male participants of the National Walkers' Health Study.

RESULTS

Standard regression analyses showed that body mass index (BMI) was inversely and significantly associated with walking distance (kg/m(2) per km/week) in elderly (slope (SE): -0.032 (0.008)), senior (-0.045 (0.005)) and middle-aged men (-0.037 (0.007)), as were their waist circumferences (-0.090 (0.025), -0.122 (0.012) and -0.091 (0.015) cm per km/week, respectively), and that these slopes remained significant when adjusted statistically for reported weekly servings of meat, fish, fruit and alcohol. However, percentile regression analyses showed that the declines in BMI per km/week walked were greater at the higher than the lower percentiles of the BMI distribution. In men > or =74 years old the decline per km walked was 4.9-fold greater among the heaviest men (that is, 90th BMI percentile; -0.076 kg/m(2) per km/week) than among the leanest men (that is, 10th BMI percentile; -0.015 kg/m(2) per km/week). The differences in slope at the 90th compared to the 10th BMI percentile were 5.4-fold among men 55-74 years old and sixfold among men 35-54 years old. Per km/week walked, the declines at the 90th percentile of waist circumference were also greater than at its 10th percentile, and intermediate for percentiles in between. Whereas standard regression analyses suggest that the average declines in BMI per km/week walked reported here are consistent with those reported previously per km/week run in male runners 35-54 years old (-0.036 (0.001) kg/m(2) per km/week) and > or =50 years old (-0.038 (0.001) kg/m(2) per km/week), percentile regression analyses showed that when adjusted to the leaner body weights of the runners the declines per km walked were between 49% and 59% less for walkers than runners.

CONCLUSIONS

Declines in BMI and waist circumferences with walking distance depend upon the percentile of the BMI distribution, with the decline per km walked being significantly greater among heavier men.

Severe weight loss in HIV / HCV-coinfected patients treated with interferon plus ribavirin: incidence and risk factors

Weight loss is reported by more than 20% of hepatitis C virus (HCV)-monoinfected patients treated with the peg-interferon (peg-IFN) and ribavirin combination. The aim of this study was to determine the incidence and risk factors of severe weight loss (> or =10%) in human immunodeficiency virus (HIV) / HCV-coinfected patients participating in a randomized, controlled 48-week trial comparing peg-IFN alpha 2b plus ribavirin with IFN alpha-2b plus ribavirin. Univariate and multivariate analyses were used to identify links with antiretroviral treatments, anti-HCV therapy and clinical and laboratory findings. One hundred eleven (28.9%) of 383 patients who received at least one dose of anti-HCV treatment subsequently had severe weight loss. Among patients who took at least 80% of the planned total dose, severe weight loss occurred in 74 patients (32.7%). In multivariate analysis, age >40 years [hazard ratio (HR), 1.59; 95% CI 1.09 to 2.31; P = 0.016], body mass index (BMI) >22 (HR, 1.72; 95% CI, 1.16 to 2.55; P = 0.0069), peg-IFN alpha-2b (HR, 1.82; 95% CI, 1.24 to 2.69; P = 0.0022) and female sex (HR, 1.60; 95% CI, 1.05 to 2.43; P = 0.027) were associated with severe weight loss. In contrast, patients taking non-nucleoside reverse transcriptase inhibitors (NNRTI)-containing antiretroviral regimens were less likely to lose weight (HR, 0.62; 95% CI, 0.39 to 0.96; P = 0.034). Lipodystrophy tended to occur more frequently in patients who had severe weight loss than in the other patients (26.1%vs 17.6%; P = 0.0682) and patients whose weight loss >5% persisted 24 weeks after the completion of anti-HCV therapy (n = 58 / 111) were more likely to be receiving stavudine-based antiretroviral therapy, suggesting that mitochondrial toxicity plays some role in weight loss. These findings show that severe weight loss is a frequent side effect of anti-HCV therapy in HIV / HCV-coinfected patients. The underlying mechanisms remain to be identified.

Overweight and obesity in a Swiss city: 10-year trends

Background

Increased rates of overweight/obesity have been reported in recent years in developed countries. This population study of healthy subjects evaluated the changes in overweight/obesity prevalence in 2003, compared with 1993, and determined the association of age, sex and leisure-time activity with body mass index (BMI), fat-free mass index (FFMI) and fat mass index (FMI).

Design

Two transversal samples of convenience.

Participants

Healthy volunteers (1993, n = 802; 2003, n = 1631).

Methods

Fat-free mass was determined using the bioelectrical impedance multiple regression equation. Multivariable linear regression, including confounding variables (age, sex, leisure-time activity), was used to model the body composition evolution between the 1993 and the 2003 subjects.

Results

BMI and FMI were higher in 2003 than in 1993, P < 0.001. FFMI was not higher in 2003 than in 1993, P = 0.38. More subjects were overweight/obese in 2003 than in 1993 (27.5 versus 17.2%, chi-square P < 0.001), and had a high FFMI (30.2 versus 21.8%, chi-square P < 0.001) and high FMI (28.0 versus 20.3%, chi-square P < 0.001). Multivariate linear regressions showed that leisure-time activity was negatively, and sex, age and inclusion year were positively associated with BMI, FFMI and FMI (the exception was a negative association with sex) (P < 0.001).

Conclusion

Overweight prevalence increased between 1993 and 2003 in a Swiss city, and was associated with a higher fat mass. This observation remained statistically significant after adjustment for age, sex and leisure-time activity.

Scaling of human body composition to stature: new insights into body mass index

BACKGROUND

Although Quetelet first reported in 1835 that adult weight scales to the square of stature, limited or no information is available on how anatomical body compartments, including adipose tissue (AT), scale to height.

OBJECTIVE

We examined the critical underlying assumptions of adiposity-body mass index (BMI) relations and extended these analyses to major anatomical compartments: skeletal muscle (SM), bone, residual mass, weight (AT+SM+bone), AT-free mass, and organs (liver, brain).

DESIGN

This was a cross-sectional analysis of 2 body-composition databases: one including magnetic resonance imaging and dual-energy X-ray absorptiometry (DXA) estimates of evaluated components in adults (total n=411; organs=76) and the other a larger DXA database (n=1346) that included related estimates of fat, fat-free mass, and bone mineral mass.

RESULTS

Weight, primary lean components (SM, residual mass, AT-free mass, and fat-free mass), and liver scaled to height with powers of approximately 2 (all P<0.001); bone and bone mineral mass scaled to height with powers >2 (2.31-2.48), and the fraction of weight as bone mineral mass was significantly (P<0.001) correlated with height in women. AT scaled weakly to height with powers of approximately 2, and adiposity was independent of height. Brain mass scaled to height with a power of 0.83 (P=0.04) in men and nonsignificantly in women; the fraction of weight as brain was inversely related to height in women (P=0.002).

CONCLUSIONS

These observations suggest that short and tall subjects with equivalent BMIs have similar but not identical body composition, provide new insights into earlier BMI-related observations and thus establish a foundation for height-normalized indexes, and create an analytic framework for future studies.

Sleep and metabolic control: waking to a problem?

1. The aim of the present review is to outline: (i) the association between sleep and metabolism; (ii) how sleep duration influences the development of disease; and (iii) how sex differences, ageing and obesity may potentially influence the relationship between sleep, metabolic control and subsequent disease. 2. Sleep is associated with a number of endocrine changes, including a change in insulin action in healthy young individuals. Sleep duration shows a prospective U-shaped relationship with all-cause mortality, cardiovascular disease and Type 2 diabetes. 3. Chronic sleep restriction is becoming more common. Experimental sleep restriction impedes daytime glucose control and increases appetite. 4. The sex hormones oestrogen and testosterone influence sleep duration and quality and may account for sex differences in the prevalence of sleep-related disorders. 5. Ageing is associated with a decreased sleep duration, decreased muscle mass and impaired insulin action. 6. Obesity impairs insulin action and is associated with the incidence and severity of obstructive sleep apnoea. 7. Sleep plays an integral role in metabolic control. Consequently, insufficient sleep may represent a modifiable risk factor for the development of Type 2 diabetes. The challenge ahead is to identify how sex differences, ageing and obesity could potentially influence the relationship between sleep and metabolism.

The new Geriatric Nutritional Risk Index is a good predictor of muscle dysfunction in institutionalized older patients

BACKGROUND & AIMS

The validity of Geriatric Nutritional Risk Index (GNRI), in predicting nutrition-related risk of complications in the elderly, has been recently underscored. Malnutrition may results also in muscle function impairment. Thus, the present study aims to investigate if GNRI might be a reliable detector of muscle dysfunction in institutionalized older people.

METHODS

In total, 153 institutionalized elderly (71 males, 82 females; mean age+/-SD: 75.2+/-8.4; range: 65-96) were studied in anthropometric parameters, serum albumin concentration and total score on GNRI. Muscle function was assessed by handgrip strength (HG).

RESULTS

Women were significantly older than men and presented lower values of HG and arm muscle area (AMA). In overall population, GNRI was significantly correlated with AMA, HG and strength for centimeter of muscle area (HG/AMA); however, in gender-separated analysis, men presented higher degrees of correlation. After dividing patients in four categories according to GNRI, a more significant difference was detected in HG and HG/AMA rather than the other clinical and anthropometric parameters. Moreover, ANOVA analysis between HG quartiles was highly significant for GNRI, AMA and HG/AMA.

CONCLUSIONS

GNRI is a good predictor of muscle dysfunction, particularly in men, and useful in identifying patients suitable for nutritional support and physical activity.

Cancer-Associated Cachexia and Underlying Biological Mechanisms

Cancer metastases (spread to distant organs from the primary tumor site) signify systemic, progressive, and essentially incurable malignant disease. Anorexia and wasting develop continuously throughout the course of incurable cancer. Overall, in Westernized countries nearly exactly half of current cancer diagnoses end in cure and the other half end in death; thus, cancer-associated cachexia has a high prevalence. The pathophysiology of cancer-associated cachexia has two principal components: a failure of food intake and a systemic hypermetabolism/hypercatabolism syndrome. The superimposed metabolic changes result in a rate of depletion of physiological reserves of energy and protein that is greater than would be expected based on the prevailing level of food intake. These features indicate a need for nutritional support, metabolic management, and a clear appreciation of the context of life-limiting illness.

Aged Men Experience Disturbances in Recovery Following Submaximal Exercise

BACKGROUND

Physiological responses to exercise of moderate intensity and duration among aged compared to young adults have yet to be clearly defined. Further, the effects of aging on the rate and effectiveness of postexercise recovery are unknown.

METHODS

Here, selected physiological responses during and following exercise of the same relative intensity were examined in untrained young and aged men.

RESULTS

Generally, the two groups displayed similar responses during 30 minutes of exercise. During recovery, however, numerous age-related differences were manifested. Relative heart rate (% peak) was higher during recovery among the aged group. Postexercise lactate remained increased longer among aged men, and blood glucose regulation was impaired during recovery. This difference in circulating glucose was associated with insulin responses whereby young, but not aged men experienced a postexercise spike. Unlike that in young men, rectal temperature among aged men continued to increase through the entire recovery period.

CONCLUSIONS

These data suggest that aged men encounter problems in recovering from submaximal exercise.

Challenges to Diagnosis of HIV-Associated Wasting

There is a wide variability in the clinical presentation of the protein energy malnutrition often characterized as wasting in patients infected with HIV. Moreover, the clinical presentation has evolved over time. Initially, protein energy malnutrition was characterized by profound weight loss and depletion of body cell mass (BCM). Recently, unrelated concurrent metabolic abnormalities, such as lipodystrophy, may complicate the diagnosis of HIV wasting. Although measures of BCM are relatively accurate for the diagnosis of HIV wasting, the optimal tools for assessing BCM are not necessarily available to the clinician. From the practical standpoint, HIV wasting may be a self-evident diagnosis in advanced stages, but effective interpretation of the early signs of HIV wasting requires familiarity with other complications included in the differential diagnosis.

RF dosimetry: a comparison between power absorption of female and male numerical models from 0.1 to 4 GHz

Realistic numerical models of human subjects and their surrounding environment represent the basic points of radiofrequency (RF) electromagnetic dosimetry. This also involves differentiating the human models in men and women, possibly with different body shapes and postures. In this context, the aims of this paper are, firstly, to propose a female dielectric anatomical model (fDAM) and, secondly, to compare the power absorption distributions of a male and a female model from 0.1 to 4 GHz. For realizing the fDAM, a magnetic resonance imaging tomographer to acquire images and a recent technique which avoids the discrete segmentation of body tissues into different types have been used. Simulations have been performed with the FDTD method by using a novel filtering-based subgridding algorithm. The latter is applied here for the first time to dosimetry, allowing an abrupt mesh refinement by a factor of up to 7. The results show that the whole-body-averaged specific absorption rate (WBA-SAR) of the female model is higher than that of the male counterpart, mainly because of a thicker subcutaneous fat layer. In contrast, the maximum averaged SAR over 1 g (1gA-SAR) and 10 g (10gA-SAR) does not depend on gender, because it occurs in regions where no subcutaneous fat layer is present.