Regulation of energy expenditure in aging humans

Mapping the Evidence for Measuring Energy Expenditure and Indicating Hypermetabolism in Motor Neuron Disease: A Scoping Review

OBJECTIVE

To map the international methods used to measure energy expenditure of adults living with motor neuron disease (MND) and to highlight discrepancies when indicating hypermetabolism in the MND literature.

BACKGROUND

A decline in the nutritional status of patients is associated with exacerbated weight loss and shortened survival. Assessments of energy expenditure, using a variety of methods, are important to ensure an adequate energy intake to prevent malnutrition-associated weight loss. Assessments of energy expenditure are also commonly used to indicate hypermetabolism in MND, although these approaches may not be optimal.

METHODS

A protocol based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping Reviews Guidelines was developed. Three electronic databases (Medline [Ovid], CINAHL [EBSCO], and Web of Science) were exhaustively searched. Identified publications were systematically screened according to predefined PICOS eligibility criteria. The primary outcome was the identification of methods used to measure energy expenditure in MND. The secondary outcome was the identification of applications of energy expenditure assessments to indicate hypermetabolism in MND.

RESULTS

Thirty-two observational primary research publications were identified. Thirteen (40.6%) were longitudinal in design, with data on repeated measurements of energy expenditure presented in 3 (9.4%). Thirteen (40.6%) were case-control studies, of which 11 use a matched control group. Pulmonary function was used to assess eligibility in 10 publications. Energy expenditure was measured using indirect calorimetry (IC) in 31 studies. Discrepancies in the durations of fasted, measurement, and washout periods were observed. Of all included publications, 50% used assessments of resting energy expenditure to identify hypermetabolism. Bioelectrical impedance analysis was used to assess body composition alongside energy expenditure in 93.8% of publications.

CONCLUSIONS

Resting energy expenditure is most frequently measured using an open-circuit IC system. However, there is a lack of a standardized, validated protocol for the conduct and reporting of IC and metabolic status in patients with MND.

Gene module regulation in dilated cardiomyopathy and the role of Na/K-ATPase

Dilated cardiomyopathy (DCM) is a major cause of cardiac death and heart transplantation. It has been known that black people have a higher incidence of heart failure and related diseases compared to white people. To identify the relationship between gene expression and cardiac function in DCM patients, we performed pathway analysis and weighted gene co-expression network analysis (WGCNA) using RNA-sequencing data (GSE141910) from the NCBI Gene Expression Omnibus (GEO) database and identified several gene modules that were significantly associated with the left ventricle ejection fraction (LVEF) and DCM phenotype. Genes included in these modules are enriched in three major categories of signaling pathways: fibrosis-related, small molecule transporting-related, and immune response-related. Through consensus analysis, we found that gene modules associated with LVEF in African Americans are almost identical as in Caucasians, suggesting that the two groups may have more common rather than disparate genetic regulations in the etiology of DCM. In addition to the identified modules, we found that the gene expression level of Na/K-ATPase, an important membrane ion transporter, has a strong correlation with the LVEF. These clinical results are consistent with our previous findings and suggest the clinical significance of Na/K-ATPase regulation in DCM.

Malnutrition by GLIM criteria in chronic pancreatitis: Prevalence, predictors, and its impact on quality of life

INTRODUCTION

Malnutrition in chronic pancreatitis (CP) has prognostic value and there is limited data on the prevalence, predictors of malnutrition in CP and its effect on Quality of life (QoL).

METHODS

A retrospective study was conducted in patients with CP to assess the prevalence of malnutrition as per the Global Leadership Initiative on Malnutrition (GLIM) criteria. Multivariable-adjusted regression was used to identify independent predictors of both malnutrition and global QoL.

RESULTS

A total of 297 patients were included and the most common etiology of CP was idiopathic (75%) and alcohol (25%). The prevalence of malnutrition was 46.4% as per GLIM criteria. On univariate analysis, the risk of malnutrition was significantly higher in alcoholic etiology (p = 0.001), current alcohol consumption (p = 0.001), smokers (p < 0.001), those having higher cumulative days of pain in last 6 months (p < 0.001) and lower daily calorie intake (p = 0.019). On multivariate analysis, malnutrition was independently associated with current alcohol consumption (Odds ratio: 3.22, p = 0.017), current smokers (OR: 2.23, p = 0.042) and those having higher cumulative days of abdominal pain (OR: 1.01, p < 0.001), while higher daily calorie intake (per 100 kcal) (OR:0.94, p = 0.023) has reduced risk of malnutrition. Malnutrition (p = 0.015) and higher cumulative days of abdominal pain (p < 0.001) were independently associated with lower global QoL in patients with CP.

CONCLUSION

Malnutrition is frequent in patients with CP; and current alcohol consumption, smoking and higher cumulative days of abdominal pain independently predicts risk of developing malnutrition. Patients with malnutrition and higher cumulative days of pain has poorer quality of life.

Overweight and obesity among non-pregnant women of reproductive age in Nigeria: findings from the 2008-2018 Nigerian Demographic and Health Survey

OBJECTIVES

Overweight and obesity are known risk factors for diabetes, heart disease, certain cancers and pregnancy-related problems. This study aimed to determine the prevalence and change in prevalence of overweight and obesity among non-pregnant women of reproductive age and relationship with individual- and community-level factors over a decade.

STUDY DESIGN

This was a cross-sectional survey with two-stage probability sampling design.

METHODS

Data sets were pooled from the 2008, 2013 and 2018 Nigerian Demographic and Health Survey - a cross-sectional, nationally representative sample of the entire Nigerian population aged 15-49 years. Body mass index (BMI) was used to classify overweight and obesity. Multilevel logistic regression was used to assess associations between overweight (25.0-29.9 kg/m²), obesity (≥30.0 kg/m²) and individual and community factors.

RESULTS

There were 76,729 non-pregnant women (38.0% in 2008, 44.5% in 2013 vs 17.5% in 2018) with a mean age of 29.0 years and a BMI of 23.0 kg/m² across the three survey periods. Overweight and obesity prevalence were 16.0% and 6.2% in 2008, 17.2% and 7.5% in 2013 and 18.1% and 9.9% in 2018, respectively. There was 76% (95% confidence interval: 44% to twofold) increased odds of obesity in 2018 compared with 2008 in adjusted analysis. Older women with at least primary education living in urban areas, ever married and from wealthier households are at a greater odd of being overweight and obese.

CONCLUSION

Over a decade, overweight and obesity prevalence increased among non-pregnant women of reproductive age in Nigeria. There is an urgent need for public health strategies and interventions to improve on deficient knowledge and low awareness about healthy foods and physical activity at individual and community levels especially in urban areas.

A multilevel analysis of overweight and obesity among non-pregnant women of reproductive age in Malawi: evidence from the 2015-16 Malawi Demographic and Health Survey

BACKGROUND

Overweight and obesity are well-known risk factors for non-communicable diseases such as cardiovascular disease, diabetes, some cancers and musculoskeletal disorders. In Malawi, the proportion of women who are overweight/obese has doubled, from 10% in 1992 to 21% in 2015-16. Therefore we aimed to explore the individual- and community-level factors associated with overweight and obesity among non-pregnant women of child-bearing age.

METHODS

Secondary analysis of the 2015-16 Malawi Demographic and Health Survey was conducted. Overweight was defined as a body mass index (BMI) of 25 to <30 kg/m2, while obesity was defined as a BMI ≥30 kg/m2. Two-level multilevel multivariable logistic regression models were constructed using a logit-link function with a binomial distribution on 7326 women living in 850 different communities.

RESULTS

At the individual level, the adjusted multilevel regression results showed that women 15-19 y of age as well as women from the poorest households had reduced odds of being overweight/obese. However, women with white collar jobs and women who were affiliated with the Church of Central Africa Presbyterian and the Roman Catholic church had increased odds of being overweight/obese. At the community level, women from urban areas and women who resided in communities with a low percentage of media exposure had increased odds of being overweight or obese. While women from poor communities had reduced odds of being overweight and obese, the proportion change in variance showed that 56, 77 and 78% of total variations in the odds of overweight, obese and overweight/obese across the communities were explained by both individual- and community-level factors. The median odds ratio showed that the likelihood of maternal overweight, obese and overweight/obese increased by 63, 39 and 84% when the women moved from low- to high-risk neighbourhoods.

CONCLUSIONS

Older women, Christian women, women with white collar jobs and women from the richest households should be targeted during policy formulation. At the community level, media coverage should be spread evenly so that health awareness messages, consequences and means of overweight and obesity prevention are getting to the targeted women. Our study revealed evidence of clustering effects of overweight and obesity at the community level, hence neighbourhood variations with respect to maternal overweight and obesity should be taken into account when designing nutritional policies.

4E-BP1 and 4E-BP2 double knockout mice are protected from aging-associated sarcopenia

BACKGROUND

Sarcopenia is the loss of muscle mass/function that occurs during the aging process. The links between mechanistic target of rapamycin (mTOR) activity and muscle development are largely documented, but the role of its downstream targets in the development of sarcopenia is poorly understood. Eukaryotic initiation factor 4E-binding proteins (4E-BPs) are targets of mTOR that repress mRNA translation initiation and are involved in the control of several physiological processes. However, their role in skeletal muscle is still poorly understood. The goal of this study was to assess how loss of 4E-BP1 and 4E-BP2 expression impacts skeletal muscle function and homeostasis in aged mice and to characterize the associated metabolic changes by metabolomic and lipidomic profiling.

METHODS

Twenty-four-month-old wild-type and whole body 4E-BP1/4E-BP2 double knockout (DKO) mice were used to measure muscle mass and function. Protein homeostasis was measured ex vivo in extensor digitorum longus by incorporation of l-[U-¹⁴ C]phenylalanine, and metabolomic and lipidomic profiling of skeletal muscle was performed by Metabolon, Inc.

RESULTS

The 4E-BP1/2 DKO mice exhibited an increase in muscle mass that was associated with increased grip strength (P < 0.05). Protein synthesis was higher under both basal (+102%, P < 0.05) and stimulated conditions (+65%, P < 0.05) in DKO skeletal muscle. Metabolomic and complex lipid analysis of skeletal muscle revealed robust differences pertaining to amino acid homeostasis, carbohydrate abundance, and certain aspects of lipid metabolism. In particular, levels of most free amino acids were lower within the 4E-BP1/2 DKO muscle. Interestingly, although glucose levels were unchanged, differences were observed in the isobaric compound maltitol/lactitol (33-fold increase, P < 0.01) and in several additional carbohydrate compounds. 4E-BP1/2 depletion also resulted in accumulation of medium-chain acylcarnitines and a 20% lower C2/C0 acylcarnitine ratio (P < 0.01) indicative of reduced β-oxidation.

CONCLUSIONS

Taken together, these findings demonstrate that deletion of 4E-BPs is associated with perturbed energy metabolism in skeletal muscle and could have beneficial effects on skeletal muscle mass and function in aging mice. They also identify 4E-BPs as potential targets for the treatment of sarcopenia.

Age-associated changes of resting energy expenditure, body composition and fat distribution in Chinese Han males

Age-related alterations in whole body composition, particularly, reduced fat free mass (FFM) and increased fat mass (FM), lead to a progressive decline in resting energy expenditure (REE). Similarly, regional body composition and fat distribution changes with age might also contribute to an overall lower REE. This study investigated the influence of age on REE, regional body composition and fat distribution, including subcutaneous fat (SF) and visceral fat (VF), in a Chinese Han population as well as their contributions to age-related changes in REE. One hundred and two males aged 31-83 years old underwent dual-energy X-ray absorptiometry (DXA) which measured whole body and regional FM and FFM. SF and VF were measured by magnetic resonance imaging (MRI) and REE by indirect calorimetry. Age was significantly negatively correlated with REE (r = -0.37), total FFM (r = -0.25), upper limbs FFM (r = -0.32), lower limbs FFM (r = -0.34) and showed positive association with trunk FFM (β=0.926). FM, SF and VF decreased in older age groups after an initial rise up to 55-65 years. REE correlated positively to FM, FFM, SF, VF and showed significant association with age (β = -0.254) independent of age-associated changes in body composition. The regional alterations in body composition with age were explained by changes in trunk FFM (β = 0.926). Age-related decline in REE were not solely due to alterations in FM and FFM. Therefore, the changes in regional body composition, fat distribution and REE which occur during aging could be explained by disparities in race, ethnicity, diet, physical activity, and lower specific metabolic rates of FFM components.

Characterization of a Long Non-Coding RNA, the Antisense RNA of Na/K-ATPase α1 in Human Kidney Cells

Non-coding RNAs are important regulators of protein-coding genes. The current study characterized an antisense long non-coding RNA, ATP1A1-AS1, which is located on the opposite strand of the Na/K-ATPase α1 gene. Our results show that four splice variants are expressed in human adult kidney cells (HK2 cells) and embryonic kidney cells (HEK293 cells). These variants can be detected in both cytosol and nuclear fractions. We also found that the inhibition of DNA methylation has a differential effect on the expression of ATP1A1-AS1 and its sense gene. To investigate the physiological role of this antisense gene, we overexpressed the ATP1A1-AS1 transcripts, and examined their effect on Na/K-ATPase expression and related signaling function in human kidney cells. The results showed that overexpression of the ATP1A1-AS1-203 transcript in HK2 cells reduced the Na/K-ATPase α1 (ATP1A1) gene expression by approximately 20% (p < 0.05), while reducing the Na/K-ATPase α1 protein synthesis by approximately 22% (p < 0.05). Importantly, overexpression of the antisense RNA transcript attenuated ouabain-induced Src activation in HK2 cells. It also inhibited the cell proliferation and potentiated ouabain-induced cell death. These results demonstrate that the ATP1A1-AS1 gene is a moderate negative regulator of Na/K-ATPase α1, and can modulate Na/K-ATPase-related signaling pathways in human kidney cells.

Weight Loss in Parkinson's Disease: The Relationship with Motor Symptoms and Disease Progression

Objectives

To determine the prevalence of weight loss (WL) in PD patients, its relationship to the severity of motor manifestations and appetite changes.

Methods

144 PD patients and 120 controls were evaluated in a single session. All subjects were asked about changes in body weight and appetite. PD patients were examined with the UPDRS-III and the Hoehn and Yahr (HY) scales. Subscores of tremor, bradykinesia /rigidity, and non-dopaminergic symptoms (NDS) were analyzed individually. Multivariable logistic regression analysis was used to determine an association between WL and PD motor manifestations.

Results

48.6 % of PD patients presented WL compared to 20.8 % of controls (p < 0.001). Weight losers were significantly older and had longer disease duration, higher scores in HY stages, UPDRS-III, and NDS-subscore. Multivariable logistic regression analysis demonstrated that WL was associated with NDS-subscore (p= 0.002; OR: 1.33) and older age (p= 0.037; OR: 1.05). Appetite in PD cases losing weight was unchanged (35.7 %), decreased (31.4 %), or even increased (32.9).

Conclusions

Our results showed that WL occurs in almost half of PD patients and it is largely the consequence of disease progression rather than involuntary movements or a decrease in food intake.

Resting energy expenditure in male athletes with a spinal cord injury

OBJECTIVE

To investigate whether there are differences in the resting energy expenditure (REE) and body composition of athletes with a spinal cord injury (SCI) compared to active able-bodied controls.

DESIGN

In this cross sectional study, male athletes with a SCI were compared to active able-bodied controls matched for age, stretch stature and body mass. In addition, the accuracy of standard REE prediction equations in estimating REE was assessed.

PARTICIPANTS

Seven male wheelchair athletes with a SCI and six matched active able-bodied controls volunteered to participate.

OUTCOME MEASURES

REE was measured using indirect calorimetry and estimated using population-specific prediction equations. Body composition (lean tissue mass, fat mass and bone mineral content) was measured by dual energy X-ray absorptiometry (DXA).

RESULTS

While absolute and adjusted REE in the athletes with SCI was lower than controls, this difference was not significant (P = 0.259). When adjusted for lean tissue mass (LTM), REE was significantly higher (P = 0.038) in the athletes with SCI compared to the controls (146 ± 29kJ/kg LTM vs. 125 ± 8kJ/kg LTM). LTM was significantly lower in the athletes with SCI (44.35 ± 6.98 kg) compared to the able-bodied controls (56.02 ± 4.93 kg; P < 0.01). The differences between predicted and measured REE in the athletes with SCI were not statistically significant (except for the Owen equation), however there was no significant correlation between the measures.

CONCLUSION

This suggests that existing prediction equations used to estimate energy requirements may require modification for athletes with SCI.

Emotional eating and weight regulation: a qualitative study of compensatory behaviors and concerns

BACKGROUND

Emotional eating, or overeating in response to negative emotions, is a behavior endorsed by both normal weight and people with overweight/obesity. For some individuals, emotional eating contributes to weight gain and difficulties losing weight. However, there are also many who engage in emotional eating who maintain a normal weight. Little is known about the mechanisms by which these individuals are able to regulate their weight.

METHODS

The present study seeks to gain insight into the behaviors of individuals of normal weight who engage in emotional eating through a series of one-on-one, 1-h long, qualitative interviews. Interviews were semi-structured and guided by questions pertaining to participants' compensatory behaviors used to regulate weight and concerns regarding their emotional eating. All interviews were transcribed and then objected to a thematic analysis of their content.

RESULTS

The results of this analysis showed that participants endorsed using physical activity, controlling their eating behaviors, and engaging in alternative stress reduction and coping strategies to mitigate the effects of their emotional eating. They reported concern over the effects of emotional eating on their weight, body image, and health and saw this behavior as an unhealthy coping mechanism that was difficult to control.

CONCLUSIONS

These results suggest that programs promoting exercise, mindful eating, emotion regulation, and positive body image could have a positive effect on emotional eaters who struggle to maintain a healthy weight.

Body Composition Assessment and Nutritional Status Evaluation in Men and Women Portuguese Centenarians

OBJECTIVES

To assess body composition, nutritional status and its differences between genders in a sample of Portuguese centenarians.

DESIGN

Observational cross-sectional study.

SETTING

Centenarians recruited in Portugal, able to give informed consent.

PARTICIPANTS

A total of 252 subjects, with a median age of 100 years, mostly women (77.8%) who accepted to participate in the study, during the period of 2012 to 2014.

MEASUREMENTS

Anthropometric data collected (weight, height, BMI, waist circumference, hip and waist/hip ratio) were evaluated according to WHO criteria. A portable tetrapolar bioimpedance analyzer was used to calculate body composition and to assess resting metabolism. Nutritional status was evaluated according to three different criteria: BMI, waist circumference and body fat percentage using anthropometric equations and bioimpedance.

RESULTS

We observed an overall mean weight of 51.02±11.03Kg, height of 1.55±0.07m and a BMI of 21.07±3.69Kg/m2. For most of the evaluated parameters, we found substantial differences between genders. The prevalence of underweight and overweight were 25.3% and 13.3%, respectively. Only 5 subjects were obese. Overweight subjects were mostly men (W=10.6% vs. M=22.6%), whereas women were more underweight (W=28.7% vs. M=13.2%). When considering the waist circumference, 26.5% were above the cut-off value. Most of centenarians (72.9%) had a healthy level of visceral fat. This measurement was highly correlated with waist circumference (r= 0.687, p<0.001). The mean of body fat mass was 10.69±6.50Kg, fat-free mass 40.87±7.60Kg and total body water 27.54±6.25Kg. According to body fat mass criteria assessed by bioimpedance, the prevalence of obesity in study population was 6.0% with no gender differences (p = 0.225). Obesity prevalence using anthropometric equations was higher (Deurenberg: 77.7% and Gallagher: 42.8%) than the obtained value by bioimpedance analysis, although according to Bland-Altman analysis both equations showed a good agreement (Deurenberg: 95.8% and Gallagher: 97%) with bioimpedance method. The prevalence of hypohydration (12.9%) was tendentiously higher in women compared to men (W= 15.4% vs. M= 5.0%, p=0.087). Despite the frequency of osteoporosis was higher in women (W = 71.85% vs. M = 28.15%), 95% of men revealed criteria for osteoporosis. Resting metabolic rate (RMR) was significantly different between genders using bioimpedance analysis (W= 1123.33± 173.91; M= 1350.10± 188.88; p<0.001) or Harris Benedict equation (W= 934.92± 102.60; M= 1018.85± 171.68; p=0.001). Bland- Altman analysis between methods indicate that there was an agreement of 97.6%. The overall mean metabolic age obtained was 83.52±1.11 years, well below the chronologic age (p<0.001).

CONCLUSION

In Portuguese centenarians, clinical and nutritional approach should be improved on the gender basis. In relation to nutritional status, centenarians were more frequently underweight than overweight. The thinness could be a natural process, contributing for the longevity being rather overweight a reducing factor in life expectancy. BMI and waist circumference showed a good correlation with body fat percentage. Despite the results of Bland- Altman analysis, Deurenberg and Gallagher equations are not suitable to evaluate obesity prevalence in centenarians. Harris Benedict equation seems to be a good option to measure RMR in centenaries, when BIA is not available. Body composition and nutritional characterization of Portuguese centenarians are relevant contribution in scientific evidence production for the action plan of healthy ageing in Europe (2012-2020) and also for clinical practice.

Strength and aerobic training in overweight females in Gdansk, Poland

We compared the effects of 16-week-training on rest metabolic rate, aerobic power, and body fat, and the post-exercise effects upon rest oxygen uptake and respiratory exchange ratio in overweight middle-aged females. Twenty nine overweight women (BMI 29.9 ± 1.2 kg*m^-2) participated in training (3 days a week). The subjects were divided onto groups of aerobic (AT) and strength (ST) training. The results showed that the total body mass decrease and VO₂ max increase did not differ in both groups. Decrease in waist circumference after 16 weeks was higher in the ST group. In the ST group fat-free mass increased during the first 8 weeks. Rest metabolic rate was increased significantly at 16th week compared to initial value in ST group only. Significant increase in post-exercise resting VO₂ and respiratory exchange ratio at 12 and 36 h was observed after the strength training session only. Increase in rest metabolic rate and post-exercise rest energy expenditure occurred after strength training but not after aerobic training despite the similar increase in aerobic power. The effect of 8-16 weeks of strength training on body mass decrease was higher in comparison to aerobic training.

Prevalence of overweight and obesity in non-institutionalized people aged 65 or over from Spain: the elderly EXERNET multi-centre study

Coupled with the growth of the older population, an increase in the prevalence of overweight and obesity in this age group has occurred in the last decades. The main aims of the present study were (i) to provide an updated prevalence of overweight and obesity in a representative sample of the Spanish elderly population; (ii) to calculate the prevalence of sarcopenic obesity (SO) and (iii) to analyse the relationships between adiposity measurements and lifestyle. A cross-sectional study was carried out in a sample of 3136 persons representative of the non-institutionalized population ≥65 years of age. Anthropometric measurements were obtained using standardized techniques and equipment. Overall, 84% of the population can be categorized as overweight and/or obese. The present study indicates that 67% of the Spanish elderly population has an increased percentage of fat mass and more than 56% suffer from central obesity. Moreover, SO is present in 15% of the Spanish elderly population. Finally, a strong relationship between both physically active and sedentary lifestyles and the level of adiposity was found. Prevalence of overweight and obesity among elderly people in Spain is very high and is still increasing. Lifestyle seems to be a determinant factor in the development of obesity among elderly people.

Energy intake and expenditure profile in chronic peritoneal dialysis patients complicated with circulatory congestion

BACKGROUND

Circulatory congestion is an adverse predictor of mortality in peritoneal dialysis (PD) patients.

OBJECTIVE

This study evaluated the nutritional status, energy intake, and expenditure profile of PD patients with and without previous circulatory congestion.

DESIGN

We conducted a cross-sectional study in 244 PD patients, of whom 92 had previous circulatory congestion. We estimated dietary energy intake by using a locally validated 7-d food-frequency questionnaire and by assessing resting energy expenditure (REE) and total energy expenditure (TEE) with indirect calorimetry and a locally validated physical activity questionnaire, respectively.

RESULTS

In comparison with those without circulatory congestion, patients with previous circulatory congestion were more malnourished by subjective global assessment (59% compared with 36%; P < 0.001), had lower handgrip strength, had lower midarm muscle circumference, had lower dietary protein (0.98 +/- 0.45 compared with 1.19 +/- 0.44 g x kg(-1) x d(-1); P < 0.001), and had lower energy intake (92.5 +/- 37.0 compared with 110.9 +/- 35.7 kJ x kg(-1) x d(-1); P < 0.001) but had higher C-reactive protein (P = 0.025) and higher REE (P < 0.001). However, no difference in TEE was noted between the 2 groups, which indicated lower activity energy expenditure among patients with previous circulatory congestion. The resulting energy balance was significantly more negative for patients with previous circulatory congestion than for those without previous circulatory congestion (P = 0.050). Furthermore, the prevalence of malnutrition increased with increasing episodes of circulatory congestion (P = 0.017).

CONCLUSIONS

Patients with previous circulatory congestion had significantly more inflammation, more muscle wasting, and higher REE but lower activity energy expenditure and energy and protein intakes in keeping with an anorexia-cachexia syndrome. The mechanisms of increased REE and reduced energy intake among patients with previous circulatory congestion warrant further investigation.

Hypermetabolism in ALS patients: an early and persistent phenomenon

The malnutrition common among patients with ALS can be attributed in some cases to increased resting energy expenditure (REE). However, the origins and evolution of this hypermetabolism have yet to be fully elucidated. The aim of the present study was to monitor REE over time in patients with ALS and to identify factors that may explain any variation observed. ALS patients underwent nutritional, neurological and respiratory assessment every 6 months for 2 years (or until they died or became physically incapable of being examined). Sixty-one patients were studied. At inclusion, 47.5% exhibited hypermetabolism, with a mean measured REE (mREE) 19.7 +/- 6.4% higher than the mean calculated REE (cREE) (P < 0.0001). The hypermetabolism persisted when mREE was normalized for fat free mass (FFM): 35.1 +/- 4.2 versus 32.3 +/- 4.7 kcal/kg day(-1) (P = 0.02) in hypermetabolic and normometabolic patients, respectively. In univariate analysis, mREE was negatively correlated with age and positively correlated with BMI, FFM, energy and protein intakes, and albumin level. No correlation was found with neurological scores, disease characteristics, respiratory function and survival. Multivariate analysis revealed no significant factors. Only 10 of 45 patients in whom REE was measured at least twice changed their metabolic status. Neither mREE nor mREE/cREE varied significantly over time, despite deteriorating neurological, nutritional and respiratory parameters (P < 0.0001), and an increase in mREE/FFM (P = 0.01). This study confirms that about 50% of ALS patients are hypermetabolic, and 80% show no change in metabolic status over time. Thus, metabolic status (a clinically useful indicator of the need for nutritional support) can be determined early in the evolution of the disease. The origin of hypermetabolism in this context remains unknown, but growing evidence points to mitochondria as having an important role.

Target population for clinical trials on sarcopenia

The term "sarcopenia" describes the progressive decline of muscle mass, strength and function occurring with aging. It is not considered a disease, but the direct consequence of the aging process on the skeletal muscle. Multiple demographic (e.g. gender, race), biological (e.g. inflammatory status) and clinical (e.g. diabetes, metabolic syndrome, congestive heart failure, medications) factors are able to influence (positively or negatively) the skeletal muscle quality and quantity. The extreme paucity of clinical trials on sarcopenia in literature is mainly due to difficulties in designing studies able to isolate the aging process from its multiple and interconnected consequences. In the present review, we present the major factors to consider as potential sources of biased results when evaluating potential candidates for clinical trials on sarcopenia. The development of clinical trials exploring the nature of the sarcopenia process is urgent, but several controversial issues on this hallmark of aging still need clarification.

Keeping the young-elderly healthy: is it too late to improve our health through nutrition?

Healthy older individuals can take several measures to preserve and improve their health. Even if past nutritional and lifestyle practices were not optimal, much can be done to reduce the risk of chronic disease and disability in future years. The first challenge is to recognize and address the profound changes in body composition that occur with aging. Older persons tend to accumulate relatively more body fat and less lean body mass, ie, muscle and bone. With a gain in body weight, which usually occurs, these changes are exaggerated. Because muscle tissue has a much higher metabolic rate than does fat tissue, older individuals generally develop lower metabolic rates. To avoid excess weight gain, older individuals must make major restrictions in caloric intake and increases in energy expenditure. Women experience changes in body composition similar to those in men, with changes becoming more prominent at menopause. Exercise improves body composition among healthy elderly, both by reducing fat mass and by increasing bone and muscle mass, thereby helping to restore higher metabolic rates. In men and women aged >/=65 y and taking calcium and vitamin D supplements for 3 y, the rate of bone loss slowed and the incidence of nonvertebral fractures was reduced. Several population studies of older persons show that following nutritional and lifestyle guidelines for cancer prevention reduces risk by one-third. Improving serum lipid concentrations in adults over 65 y of age with coronary artery disease decreases the risk of future cardiac events by as much as 45%. Furthermore, the greatest benefit from control of hypertension is in older individuals.

Hypermetabolism in ALS: correlations with clinical and paraclinical parameters

Despite a reduction in fat-free mass (FFM), a hypermetabolism has been reported with an average of 10% in amyotrophic lateral sclerosis (ALS) patients as compared with a healthy population. The objectives of this study were to confirm the level of hypermetabolism determined by using indirect calorimetry in 168 patients with a probable or a definite ALS and to study correlations with survival. Consecutive evaluations of resting energy expenditure (REE) were performed from diagnosis to the proximity of death in 44 ALS patients. Differences with the calculated value determined a DeltaREE. FFM was given by bioimpedance. At T(1), REE was significantly increased by an average of 14% as compared with the calculated value. 62.3% of ALS patients were considered as hypermetabolic. REE was correlated in univariate analysis with age, sex, clinical form at onset, presence of a denutrition, weight, FFM, phase angle and ALS Functional Rating Scale (ALSFRS). In multivariate analysis, REE was linked to age and FFM. DeltaREE was correlated in univariate analysis with sex, phase angle and manual muscle testing (MMT). In multivariate analysis, age and sex remained significantly correlated. During progression of ALS, REE levels remained higher than calculated values with a trend to decrease at proximity of death, whereas FFM remained stable. From T(1), survival was linked to MMT, ALSFRS, vital capacity, REE and phase angle. We confirmed the existence of a stable hypermetabolic state in ALS which depends mainly on age, sex and FFM. REE is a prognostic factor for survival in univariate analysis.

Greater than predicted decrease in resting energy expenditure with age: cross-sectional and longitudinal evidence

OBJECTIVE

To determine whether the age-related decrease in resting energy expenditure (REE) is explained by variations in body composition.

DESIGN

In Study 1, adult subjects (20-70 years) from the Quebec Family Study were classified into five different age groups. Body composition was measured by hydrodensitometry to determine fat mass and fat-free mass as predictors of REE. In the youngest group of individuals these predictors were used to plot a reference regression that was then used to predict REE in the other age groups. In Study 2, this issue was investigated in a longitudinal design (6-year follow-up). Subjects were subdivided into three groups and a reference regression was plotted at the beginning of the follow-up and was then used to predict REE 6 years later in the three age groups.

SUBJECTS

In Study 1, 627 adults (288 men and 339 women), aged between 20 and 70 years. In Study 2, 191 adults (93 men and 98 women).

RESULTS

In Study 1, measured REE was 329, 302, 528 and 636 kJ/day (P < 0.0001) below predicted REE at 34, 44, 54 and 64 years, respectively. In Study 2 the most marked deviation from predicted REE in response to the 6-year follow-up in men was observed in young adults (-548 kJ/day, P < 0.001) while in women, the largest deviation occurred later in life (-720 kj/day, P < 0.001).

CONCLUSION

Aging is accompanied by a decrease in REE that is significantly greater than what is predicted by variations in body composition. This decrease may reach a mean level of about 500-800 kj/day.

Altered body composition affects resting energy expenditure and interpretation of body mass index in children with spinal cord injury

BACKGROUND

Individuals with spinal cord injury (SCI) typically undergo changes in their body composition (reduction in lean body mass and an increase in fat mass) that can lead to secondary complications associated with diminished physical activity and obesity.

METHODS

This study used dual energy X-ray absorptiometry (DXA) to estimate the total lean tissue mass (LTM), total body fat, and total bone mineral content (BMC) to assess the relationship between body mass index (BMI), body composition, and resting metabolic rate (RMR) in a group of children with SCI who were matched with able-bodied controls for age and sex. Body composition and RMR were measured in 18 boys and 9 girls (10-21 years of age) who had a SCI in the previous 1 to 3 years and in 27 age- and sex-matched controls.

RESULTS

Children with SCI had significantly lower mean LTM than control subjects (37.6 +/- 9.6 kg and 46.7 +/- 9.2 kg, respectively; P < 0.001) and higher percent body fat (26.4 +/- 7.9% and 20.2 +/- 8.5%, respectively; P < 0.02) as measured by DXA, despite their reduced BMI (18.9 +/- 3.8 kg/m2 and 21.2 +/- 2.9 kg/m2, respectively; P < 0.01). Children with SCI had lower RMR than the controls subjects (1213 +/- 334 kJ/d and 1511 +/- 257 kJ/d, respectively), but there was no difference in RMR when adjusted for LTM.

CONCLUSION

Children with SCI have lower RMRs that are associated with their reduced LTM. The reduction in LTM and RMR may predispose children with SCI to relative gains in body fat. BMI significantly underestimates body fat in children with SCI.

Relationship between ghrelin and energy expenditure in healthy young women

Ghrelin is a novel peptide that has been isolated from human and rat stomach tissues. Despite its known stimulatory effects on appetite and eating behavior, little information is available regarding its relationship with energy expenditure in normal-weight humans. To address this issue, we examined the relationship between serum ghrelin and resting metabolic rate (RMR), the thermic effect of food (TEF), fasting and postprandial respiratory quotient, physical activity level, peak aerobic capacity (VO(2 peak)), energy intake, and psychological measures of feeding behavior. We recruited 65 young healthy women and determined RMR and TEF by indirect calorimetry after a 12-h fast. Physical activity was determined by a leisure time physical activity questionnaire; VO(2 peak) was determined by bicycle ergometer test to exhaustion; energy intake was determined by a 24-h dietary recall; and food behavior was determined by a three-factor eating questionnaire. Our cohort showed a broad range of body mass index (range, 16.8-28.3 kg/m2), RMR (range, 820-1550 kcal/d), TEF (range, 74.4-136.5 kcal/d), and percent body fat (range, 14.0-37.7%). We noted significant inverse correlations between ghrelin and RMR (r = -0.350, P = 0.004) and TEF (r = -0.396, P = 0.001). These inverse correlations persisted after statistical control for both fat-free mass and fat mass (ghrelin vs. RMR partial, r = -0.284, P = 0.024; and ghrelin vs. TEF partial, r = -0.329, P = 0.01) and insulin levels (ghrelin vs. RMR partial, r = -0.255, P = 0.046; and ghrelin vs. TEF partial, r = -0.287, P = 0.024) using partial correlation analysis. We also observed a significant inverse correlation between ghrelin and daily caloric intake (r = -0.266, P = 0.032), but ghrelin levels were not significantly correlated with fasting (r = -0.002), postprandial respiratory quotient (r = -0.016), leisure time physical activity (r = 0.104), VO(2 peak) (r = 0.138), dietary disinhibition (r = -0.071), dietary restraint (r = 0.051), or feeling of general hunger (r = -0.028). These results suggest that higher levels of ghrelin are associated with low levels of resting and postprandial thermogenesis, which is independent of individual differences in fat-free mass and fat mass. Although speculative, serum ghrelin may play a role in the regulation of energy homeostasis by acting as a hormonal marker of increased energy efficiency.

The effect of age on prepro-orexin gene expression and contents of orexin A and B in the rat brain

Orexin A and B (hypocretin 1 and 2) are hypothalamic peptides, which are synthesized in the lateral hypothalamus. Orexins participate in the regulation energy balance, food intake, vigilance and several endocrine and autonomic functions. The widespread projections of the orexin neurons suggest that they may have a role in coordination of different brain activities. The effects of ageing on the orexin system have not been studied previously. Prepro-orexin gene expression in the lateral hypothalamus, and the contents of orexin A and B peptides in the lateral hypothalamus and hypothalamus were measured in young, middle-aged and old (3, 12 and 24 months) rats. In the course of ageing, the expression of the prepro-orexin gene and the levels of orexin A and B decreased; the main decrease occurred by 12 months. Sleep deprivation for 6h increased slightly the expression of prepro-orexin gene in young rats. Deterioration of the orexin system may play a role in the phenomenon associated with aging, e.g. decreased consolidation of vigilance states, endocrine changes and dysfunctions of autonomic nervous system.

Age-related changes in the metabolism and body composition of three dog breeds and their relationship to life expectancy

We measured body composition and resting metabolic rates (RMR) of three dog breeds (Papillons, mean body mass 3.0 kg (n = 35), Labrador retrievers, mean body mass 29.8 kg (n = 35) and Great Danes, mean body mass 62.8 kg (n = 35)) that varied between 0.6 and 14.3 years of age. In Papillons, lean body mass (LBM) increased with age but fat mass (FBM) was constant; in Labradors, both LBM and FBM were constant with age, and in Great Danes, FBM increased with age but LBM was constant. FBM averaged 14.8% and 15.7% of body mass in Papillons and Labradors, respectively. Great Danes were leaner and averaged only 10.5% FBM. Pooling the data for all individuals, the RMR was significantly and positively associated with LBM and FBM and negatively associated with age. Once these factors had been taken into account there was still a significant breed effect on RMR, which was significantly lower in Labradors than in the other two breeds. Using the predictive multiple regression equation for RMR and the temporal trends in body composition, we modelled the expenditure of energy (at rest) over the first 8 years of life, and over the entire lifespan for each breed. Over the first 8 years of life the average expenditure of energy per kg LBM were 0.985, 0.675 and 0.662 GJ for Papillons, Labradors and Great Danes, respectively. This energy expenditure was almost 60% greater for the smallest compared with the largest breed. On average, however, the life expectancy for the smallest breed was a further 6 years (i.e. 14 years in total), whereas for the largest breed it was only another 6 months (i.e. 8.5 years in total). Total lifetime expenditure of energy at rest per kg LBM averaged 1.584, 0.918 and 0.691 GJ for Papillons, Labradors and Great Danes, respectively. In Labradors, total daily energy expenditure, measured by the doubly labelled water method in eight animals, was only 16% greater than the observed RMR. High energy expenditure in dogs appears positively linked to increased life expectancy, contrary to the finding across mammal species and within exotherms, yet resembling observations in other intra-specific studies. These contrasting correlations suggest that metabolism is affecting life expectancy in different ways at these different levels of enquiry.

Invited review: Aging and energy balance

Humans over 70 yr of age often lose weight. This appears to be due to a physiological anorexia of aging as well as a loss of lean mass (sarcopenia) and, to a lesser extent, fat mass. The causes of the physiological anorexia of aging include changes in taste and smell and a decrease in adaptive relaxation of the fundus of the stomach, which leads to more rapid antral filling and early satiation. In addition, basal and stimulated levels of the satiating hormone, cholecystokinin, are increased. In men, the decline in testosterone leads to an increase in leptin and a loss of lean mass. Although resting metabolic rate declines with aging, this is mainly due to the decline in lean body mass. Energy metabolism is also decreased due to a decline in Na+-K+-ATPase activity, decreased muscle protein turnover, and possibly changes in mitochondrial membrane protein permeability. Physical energy expenditure declines with aging. Meal-induced thermogenesis shows a delay to peak, possibly due to a delay in gastric emptying. Inadequate data are available on the effect of aging in humans on other energy-producing mechanisms such as adaptive thermogenesis. These physiological changes place older men and women at major risk of developing pathological weight loss when they develop disease states, especially those associated with cytokine elaboration.

The age-related decline in resting energy expenditure in humans is due to the loss of fat-free mass and to alterations in its metabolically active components

There is conflicting evidence as to whether the age-related decline in resting energy expenditure (REE) can be attributed to i) absolute changes in fat-free mass (FFM), ii) alterations in the composition of FFM or iii) decreasing organ metabolic rates. This study directly addressed the first and second hypotheses by quantification of metabolically active components of FFM assuming constant tissue respiration rates to calculate REE (REEc). REE was measured (REEm) in 26 young (13 females, 13 males, age 22-31 y) and 26 elderly subjects (15 females, 11 males, age 60-82 y) by indirect calorimetry and detailed body composition analysis was obtained using bioelectrical impedance analysis (BIA), dual energy X-ray absorptiometry (DXA), and MRI. Specific organ metabolic rates were taken from the literature. REEm adjusted for differences in FFM was lower in older subjects than in younger control subjects (5.43 +/- 0.61 MJ/d compared with 6.37 +/- 0.48 MJ/d; P < 0.001). Skeletal muscle mass plus liver mass accounted for 86% and 48% of the variance in REE in young and elderly subjects, respectively. The difference between REEm and REEc was 0.03 +/- 0.40 MJ/d and -0.36 +/- 0.70 MJ/d in young and elderly subjects, respectively. In the elderly 58% of the difference in variance was attributed to heart mass. REEm - REEc was -1.40 +/- 0.44 MJ/d in subjects with hypertensive cardiac hypertrophy, i.e., heart mass > 500 g, suggesting a decrease in heart metabolic rate with increasing heart mass. Excluding five elderly subjects with cardiac hypertrophy resulted in agreement between REEm and REEc in the elderly (-0.10 +/- 0.48 MJ/d). We concluded that the age-related decline in REE is attributed to a reduction in FFM as well as in proportional changes in its metabolically active components. There is no evidence for a decreasing organ metabolic rate in healthy aging.

Importance of preventing weight gain in adulthood

In the last 20 years, there has been a dramatic upsurge in the average weight of Australian adults. In this period, on average, Australian women have gained 4.8 kg, whilst Australian men have gained 3.6 kg. Consequently, the prevalence of obesity in men has increased from 8% to 19% and in women from 7% to 21%. This threatens to wipe away many recent health gains, as obesity has been associated with a wide range of chronic and debilitating illnesses, such as diabetes, heart disease, some cancers, sleep apnoea and osteoarthritis. Any weight gain in adulthood is usually as a result of an increase in fat stores, and the risk of ill-health from increasing weight actually begins at quite low BMI. Unfortunately, weight gain can be difficult or slow to reverse in the middle years because of physiological and behavioural changes that occur at this time of life. Adults should focus on preventing or minimizing weight gain over time by retaining physical activity within their daily living and by sensible dietary changes. Even if weight gain does occur with age, a regimen of regular exercise and a diet rich in fruit and vegetables and low in fat will provide some protection against a rapid decline in health.

Regulation of appetite in frail persons

Aging is often accompanied by anorexia of aging, described as a decline in appetite resulting in a lower dietary intake, followed by unexplained weight loss and adverse effects on health. This article discusses the main causes of a lack of appetite in frail elderly people. It is clear that appreciation of hedonic qualities of foods declines with age, as does the ability to regulate food intake. Carefully controlled studies, however, have shown favorable results with interventions that stimulate appetite in, frail elderly people.

Animal-assisted therapy and Nutrition in Alzheimer's disease

This study examined the influence of animal-assisted therapy, specifically fish aquariums, on nutritional intake in individuals with Alzheimer's disease (AD). Sixty-two individuals with AD who lived in specialized units were studied. Baseline nutritional data were obtained followed by a 2-week treatment period when the aquariums were introduced. The treatment data were collected daily for 2 weeks then weekly for 6 weeks. Nutritional intake increased significantly (21.1%; p <.001) when the aquariums were introduced and continued to increase during the 6-week weekly follow-up. Weight increased significantly (1.65 lbs; p < .001) over the 16-week period In addition, participants required less nutritional supplementation, resulting in health care cost savings.

Influence of fat-free mass and functional status on resting energy expenditure in underweight elders

BACKGROUND

In underweight elders, resting energy expenditure (REE) and its relationship with fat-free mass (FFM) could be modified by sarcopenia, physical activity, and functional limitation. The aims of this study were to investigate REE and its relationship with quantity and metabolic activity of FFM and to evaluate the influence of functional status on REE in underweight elderly subjects.

METHODS

Forty-eight underweight elders (BMI < 20) and 54 normal weight elderly subjects (BMI 20-30) as a control group were selected. Body composition was determined by dual energy x-ray absorptiometry (DEXA). REE was measured by indirect calorimetry. Ability in activities of daily living (ADLs) was assessed by the Katz index.

RESULTS

Underweight elders had significantly lower FFM, FFM index (FFM/height(2)), and REE than healthy subjects. REE adjusted for FFM with analysis of covariance remained significantly lower in the underweight group (1287 +/- 85 vs 1715 +/- 139 kcal/day in men, and 1124 +/- 63 vs 1366 +/- 91 kcal/day in women). Katz index in the underweight group was inversely correlated with REE (r = -0.68; p <.001) even after removal of FFM, FM, and gender, by multiple regression analysis. In this model, FFM and Katz index together explained approximately 54% of REE variability.

CONCLUSIONS

Underweight elderly subjects show a hypometabolism due to a reduction of both FFM quantity and its metabolic activity. Functional status in ADLs comes out as an important predictor of REE independently from FFM. The limited physical activity might be the underlying determinant of this hypometabolism, but further investigations are necessary to confirm this issue.

Association between obesity and a polymorphism in the beta(1)-adrenoceptor gene (Gly389Arg ADRB1) in Caucasian women

INTRODUCTION

Genetic variants affecting adrenoceptors have been suggested to influence body fatness. A putative gain-of-function polymorphism in the beta(1)-adrenoceptor was recently discovered (Gly389Arg ADRB1). We examined the association between Gly389Arg ADRB1 and obesity status in a large cohort of well-characterized individuals.

METHODS

First, a large cohort of 931 Caucasian women (55.0+/-12.2 y) were genotyped for Gly389Arg ADRBbeta1 and we examined the association of the Arg allele with body weight and BMI (Gly/Gly, n=54; Gly/Arg, n=360; Arg/Arg, n=517). To further examine phenotypes regulating energy balance and body fatness, we examined the contribution of the Arg allele to body composition (DEXA), fat distribution (CT scan), resting energy expenditure, energy and macronutrient intake, maximal oxygen capacity, and physical activity in a subsample of 214 women from the main cohort that had been carefully characterized (Gly/Gly, n=19; Gly/Arg, n=82; Arg/Arg, n=113).

RESULTS

In the entire cohort (n=931), allele frequencies were 0.25 and 0.75 for the Gly and Arg alleles, respectively. In this cohort, we found that each Arg allele was associated with greater body weight of 2.91 kg (P=0.01) and BMI of 0.86 kg/m(2) (P=0.05). Accordingly, in the subsample of women, each Arg allele was associated with greater fat mass (3.71 kg; P=0.008). Other phenotypes were not significantly associated with the presence of the Arg allele.

CONCLUSIONS

This is the first study to investigate the relationship between the Gly389Arg ADRB1 variant and obesity. We found that the Arg allele is associated with greater body weight and BMI in Caucasian women due to a greater fat mass.

Effects of habitual physical activity on the resting metabolic rates and body compositions of women aged 35 to 50 years

OBJECTIVE

To examine the effect habitual physical activity has on resting metabolic rate (RMR) and body composition (fat-free mass[FFM], fat mass, and percent body fat) in active compared to sedentary adult women.

DESIGN

RMR was measured (by indirect calorimetry) twice after a 12-hour fast at the same point of the menstrual cycle and 48 hours after exercise. FFM, fat mass and percent body fat were measured using whole body air displacement plethysmography. Energy intake and expenditure were determined using 7-day weighed-food records and activity logs.

SUBJECTS

Healthy, weight-stable premenopausal women aged 35 to 50 years classified as either active (approximately 9 hours per week of physical activity for 10 or more years) (n= 18) or sedentary (approximately 1 hour per week of physical activity) (n= 14).

STATISTICAL ANALYSES

Analysis of covariance was used to investigate differences in mean RMR (kcal/day) between the groups adjusted for FFM, and independent t tests were used to determine differences in demographic, energy expenditure, and diet variables.

RESULTS

Percent body fat and fat mass were lower (P<.0005) and RMR (adjusted for FFM) was significantly higher in the active women (P=.045) compared with sedentary controls. In the active and sedentary groups respectively, mean adjusted RMR was 1,510 kcal/day and 1,443 kcal/day, body fat was 18.9% and 28.8%, and fat mass was 11.1 kg and 18.8 kg. Groups were similar in body mass, FFM, body mass index, and age. Mean energy balance appeared to be more negative in the active group (P=.0059) due to significantly higher mean self-reported energy expenditures (P=.0001) and similar mean self-reported energy intakes (P=.52) compared with sedentary controls. These data indicate that active women who participate in habitual physical activity can maintain lower body fat and a higher RMR than sedentary controls with similar body mass, FFM, and body mass index.

APPLICATIONS/CONCLUSIONS

This research supports and emphasizes the benefits of habitual physical activity in maintaining RMR and lower body fat levels in middle-aged women.

Factors correlated with hypermetabolism in patients with amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a severe disease characterized by neurogenic amyotrophy and degeneration of upper and lower motor neurons. Although ALS patients usually experience reductions in fat-free mass (FFM), hypermetabolism via an undetermined source has also been reported.

OBJECTIVE

The objective was to clarify the metabolic level of ALS patients.

DESIGN

We measured the resting energy expenditure (REE) of 62 patients (32 men and 30 women) with ALS and investigated the factors correlated with metabolic level. Nutritional evaluation included bioelectrical impedance analysis, indirect calorimetry, and calculation of the body mass index. Neurologic assessment included an evaluation of peripheral and central neurologic deficit. Forced vital capacity was measured and smoking status was noted. A complete blood cell count was made and thyroid hormone and C-reactive protein concentrations were measured.

RESULTS

Patients were hypermetabolic, by an average of approximately 10% more than in a reference healthy population. FFM, age, and the neutrophil count were significantly associated with REE. The only variable that contributed to the prediction of REE, REE/Z100 kHz (bioimpedance at 100 kHz), REE adjusted for FFM, or the ratio of measured REE to calculated REE was the neutrophil count, which explained only a small percentage of variance in the multiple regression analysis. Hypermetabolism was not associated with a reduction in respiratory function, tobacco use, hyperthyroidism, spasticity and fasciculation intensities, or infection.

CONCLUSIONS

Our study corroborates the surprising finding that ALS patients are hypermetabolic. FFM, age, sex, manual muscular testing, the modified Norris limb score, weight, and an increase in circulating neutrophil counts correlated with the hypermetabolic state. Other factors may play a role in pathophysiologic processes that involve mitochondrial energy production or even sympathoadrenergic activation.

Frailty in older adults: evidence for a phenotype

BACKGROUND

Frailty is considered highly prevalent in old age and to confer high risk for falls, disability, hospitalization, and mortality. Frailty has been considered synonymous with disability, comorbidity, and other characteristics, but it is recognized that it may have a biologic basis and be a distinct clinical syndrome. A standardized definition has not yet been established.

METHODS

To develop and operationalize a phenotype of frailty in older adults and assess concurrent and predictive validity, the study used data from the Cardiovascular Health Study. Participants were 5,317 men and women 65 years and older (4,735 from an original cohort recruited in 1989-90 and 582 from an African American cohort recruited in 1992-93). Both cohorts received almost identical baseline evaluations and 7 and 4 years of follow-up, respectively, with annual examinations and surveillance for outcomes including incident disease, hospitalization, falls, disability, and mortality.

RESULTS

Frailty was defined as a clinical syndrome in which three or more of the following criteria were present: unintentional weight loss (10 lbs in past year), self-reported exhaustion, weakness (grip strength), slow walking speed, and low physical activity. The overall prevalence of frailty in this community-dwelling population was 6.9%; it increased with age and was greater in women than men. Four-year incidence was 7.2%. Frailty was associated with being African American, having lower education and income, poorer health, and having higher rates of comorbid chronic diseases and disability. There was overlap, but not concordance, in the cooccurrence of frailty, comorbidity, and disability. This frailty phenotype was independently predictive (over 3 years) of incident falls, worsening mobility or ADL disability, hospitalization, and death, with hazard ratios ranging from 1.82 to 4.46, unadjusted, and 1.29-2.24, adjusted for a number of health, disease, and social characteristics predictive of 5-year mortality. Intermediate frailty status, as indicated by the presence of one or two criteria, showed intermediate risk of these outcomes as well as increased risk of becoming frail over 3-4 years of follow-up (odds ratios for incident frailty = 4.51 unadjusted and 2.63 adjusted for covariates, compared to those with no frailty criteria at baseline).

CONCLUSIONS

This study provides a potential standardized definition for frailty in community-dwelling older adults and offers concurrent and predictive validity for the definition. It also finds that there is an intermediate stage identifying those at high risk of frailty. Finally, it provides evidence that frailty is not synonymous with either comorbidity or disability, but comorbidity is an etiologic risk factor for, and disability is an outcome of, frailty. This provides a potential basis for clinical assessment for those who are frail or at risk, and for future research to develop interventions for frailty based on a standardized ascertainment of frailty.

Estrogens and women's health: interrelation of coronary heart disease, breast cancer and osteoporosis

The determinants of blood levels of estrogen, estrogen metabolites, and relation to receptors and post-transitional effects are the likely primary cause of breast cancer. Very high risk women for breast cancer can now be identified by measuring bone mineral density and hormone levels. These high risk women have rates of breast cancer similar to risk of myocardial infarction. They are candidates for SERM therapies to reduce risk of breast cancer. The completion of the Women's Health Initiative and other such trials will likely provide a definite association of risk and benefit of both estrogen alone and estrogen-progesterone therapy, coronary heart disease, osteoporotic fracture, and breast cancer. The potential intervention of hormone replacement therapy, obesity, or weight gain and increased atherogenic lipoproteinemia may be of concern and confound the results of clinical trials. Estrogens, clearly, are important in the risk of bone loss and osteoporotic fracture. Obesity is the primary determinant of postmenopausal estrogen levels and reduced risk of fracture. Weight reduction may increase rates of bone loss and fracture. Clinical trials that evaluate weight loss should monitor effects on bone. The beneficial addition of increased physical activity, higher dose of calcium or vitamin D, or use of bone reabsorption drugs in coordination with weight loss should be evaluated. Any therapy that raises blood estrogen or metabolite activity and decreases bone loss may increase risk of breast cancer. Future clinical trials must evaluate multiple endpoints such as CHD, osteoporosis, and breast cancer within the study. The use of surrogate markers such as bone mineral density, coronary calcium, carotid intimal medial thickness and plaque, endothelial function, breast density, hormone levels and metabolites could enhance the evaluation of risk factors, genetic-environmental intervention, and new therapies.

Restriction of energy intake, energy expenditure, and aging

Energy restriction (ER), without malnutrition, increases maximum life span and retards the development of a broad array of pathophysiological changes in laboratory rodents. The mechanism responsible for the retardation of aging by ER is, however, unknown. One proposed explanation is a reduction in energy expenditure (EE). Reduced EE may increase life span by decreasing the number of oxygen molecules interacting with mitochondria, thereby lowering reactive oxygen species (ROS) production. As a step toward testing this hypothesis, it is important to determine the effect of ER on EE. Several whole-body, organ, and cellular studies have measured the influence of ER on EE. In general, whole-body studies have reported an acute decrease in mass-adjusted EE that disappears with long-term ER. Organ-specific studies have shown that decreases in EE of liver and gastrointestinal tract are primarily responsible for initial reductions in EE with ER. These data, however, do not determine whether cellular EE is altered with ER. Three major processes contributing to resting EE at the cellular level are mitochondrial proton leak, Na(+)-K(+)-ATPase activity, and protein turnover. Studies suggest that proton leak and Na(+)-K(+)-ATPase activity are decreased with ER, whereas protein turnover is either unchanged or slightly increased with ER. Thus, two of the three major processes contributing to resting EE at the cellular level may be decreased with ER. Although additional cellular measurements are needed, the current results suggest that a lowering of EE could be a mechanism for the action of ER.

Growth hormone enhances effects of endurance training on oxidative muscle metabolism in elderly women

The present study investigated whether recombinant human (rh) growth hormone (GH) combined with endurance training would have a larger effect on oxidative capacity, metabolism, and body fat than endurance training alone. Sixteen healthy, elderly women, aged 75 yr, performed closely monitored endurance training on a cycle ergometer over 12 wk. rhGH was given in a randomized, double-blinded, placebo-controlled design in addition to the training program. GH administration resulted in a doubling of serum insulin-like growth factor I levels. With endurance training, peak oxygen uptake increased by approximately 18% in both groups, whereas the marked increase in muscle citrate synthase activity was 50% larger in the GH group compared with the placebo group. In addition, only the GH group revealed an increase in muscle L-3-hydroxyacyl-CoA dehydrogenase activity. Body weight remained unchanged in both groups, but the GH group showed significant changes in body composition with a decrease in fat mass and an increase in lean body mass. Twenty-four-hour indirect calorimetry performed in four subjects showed a marked increase in energy expenditure with increased relative and absolute fat combustion in the two subjects receiving rhGH. In conclusion, rhGH adds to the effects of endurance training on muscle oxidative enzymes and causes a reduction in body fat in elderly women.

Resting energy expenditure, growth hormone indices, body composition and adipose tissue distribution in premenopausal women

OBJECTIVES

A significant growth hormone (GH) contribution to interindividual variance in energy expenditure (REE) in women can be hypothesized. The present study examines the independent association between physiological levels of GH function indices and REE.

SETTING

All subjects were hospitalized in the Institute of Internal Medicine of the University of Verona.

SUBJECTS

Twenty-four premenopausal overweight (BMI = 28-55 kg m-2) women aged 18-49 years.

INTERVENTIONS

REE was estimated by indirect calorimetry and body composition and fat distribution by single slice computed tomography method. GH activity and GH status were determined by measuring serum levels of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3).

RESULTS

GH indices did not show any significant correlation with REE. The relation between GH indices and REE was also examined by multiple regression analysis to account for possible confounders such as body composition, adipose tissue distribution and age. When body composition was considered, body fat and fat-free mass were the only significant predictors of REE (R2 = 0.699, P = 0.0001). The contributions of GH indices were not significant.

CONCLUSIONS

Our findings do not support the hypothesis that GH in physiological conditions could be an independent determinant of REE in women with obesity.

Weight loss in Alzheimer disease

BACKGROUND

Epidemiologic studies have shown that weight loss is commonly associated with Alzheimer disease (AD) and is a manifestation of the disease itself. The etiology of weight loss in AD appears multifactorial. Hypotheses to explain the weight loss have been suggested (eg, atrophy of the mesial temporal cortex, biological disturbances, and higher energy expenditure); however, none have been proven.

OBJECTIVE

In the first part of this article, we describe weight loss in AD (epidemiologic data and hypotheses to explain weight loss and anorexia in AD). In the second part we report the results of a longitudinal study of the changes in nutritional variables in a cohort of patients with a probable diagnosis of AD.

DESIGN

We followed subjects with AD (based on criteria of the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association) who were recruited from the Alzheimer's Disease Center in Toulouse. All subject underwent a nutritional, neuropsychologic, and functional evaluation. The Zarit scales were used to assess caregiver burden and caregiver reactions to the patients' behavioral and autonomic disorders.

RESULTS

We showed that only results of the Burden Interview and the Memory and Behavior Problems Checklist, which explored caregiver burden, predicted weight loss in AD. It is possible that caregivers who consider themselves overburdened by the disease process are not willing to invest adequate resources to allow AD patients to properly nourish themselves.

CONCLUSION

Nutritional education programs for the caregivers of AD patients seem to be the best way to prevent weight loss and improve the nutritional status of these patients.

Energy expenditure, energy intake, and weight loss in Alzheimer disease

Alzheimer disease is one of the leading causes of death among older individuals. Unexplained weight loss and cachexia are frequent clinical findings in patients with Alzheimer disease. Thus, it has been postulated that Alzheimer disease may be associated with dysfunction in body weight regulation. This brief review examines the interrelations among energy intake, energy expenditure, and body composition in Alzheimer disease. We explored whether abnormally high daily energy expenditures, low energy intakes, or both contribute to unexplained weight loss and a decline in nutritional status. Specifically, we considered studies that examined energy intake, body composition, and daily energy expenditure and its components. The application of doubly labeled water and indirect calorimetry to understand the etiology of wasting has increased our knowledge regarding the relation among energy expenditure, physical activity levels, and body composition in Alzheimer disease patients. Although the number of studies are limited, results do not support the notion that a hypermetabolic state contributes to unexplained weight loss in Alzheimer disease, even in cachectic patients. Recent findings are presented suggesting an association between abnormally elevated levels of physical activity energy expenditure and elevated appendicular skeletal muscle mass and energy intake in Alzheimer disease patients. Clinical strategies aimed at developing lifestyle and dietary interventions to maintain adequate energy intake, restore energy balance, and maintain skeletal muscle mass should be a future area of investigation in Alzheimer disease research.

Food restriction suppresses muscle growth and augments osteopenia in ovariectomized rats

We examined effects of 4 wk of food restriction on ovariectomy-related changes in muscle, bone, and plasma insulin-like growth factor I (IGF-I). Female Sprague-Dawley rats (7 mo old) were assigned to freely eating groups: sham-operated (Sham), ovariectomized (Ovx-AL), and estrogen (estradiol)-replaced Ovx (Ovx+E(2)). Ovx rats were also pair fed with Sham (Ovx-PF) or weight matched with Sham by food restriction (Ovx-FR). Ovx-AL and Ovx-PF rats had similar estrogen status and body weight; therefore, the groups were combined (group: Ovx). After treatment, body weight was approximately 10% greater in Ovx than in Sham rats (P < 0.05), and muscle weight-to-body weight ratios were comparable among all groups. Bone mineral contents of whole tibiae in Ovx-FR and Ovx were approximately 15% (P < 0.05) and approximately 6% lower than in Sham rats (P < 0.05), respectively. Plasma IGF-I was approximately 30% higher in Ovx than in Sham (P < 0.05) but was similar between Sham and Ovx-FR. IGF-I was highly correlated with body weight and muscle mass. Within non-estrogen-replaced Ovx rats, IGF-I explained approximately 19% of variance in bone mineral content after accounting for variance attributable to body weight. Findings suggest that estrogen acts indirectly on skeletal muscle and bone in rats through regulation of body growth by factors such as IGF-I.

Postabsorptive resting metabolic rate and thermic effect of food in relation to body composition and adipose tissue distribution

One hundred thirty subjects were studied to investigate relationships between the body composition and fat distribution as evaluated by computed tomography and the resting metabolic rate (RMR) as evaluated by indirect calorimetry: 82 premenopausal women (age, 18 to 52 years; body mass index [BMI], 27 to 52 kg/m2), 27 postmenopausal women (46 to 71 years; 28 to 49 kg/m2), and 21 men (18 to 70 years; 31 to 43 kg/m2). The thermic effect of food (TEF) was evaluated in all men and in 2 subgroups of 55 and 19 women. The best-fitting equations for predicting RMR, obtained by multiple regression, included the following as covariates: fat-free mass and both subcutaneous and visceral adipose tissue in premenopausal women (R2 = .55, P = .0001), fat-free mass and visceral adipose tissue in postmenopausal women (R2 = .58, P = .001), and age, with minus sign, and visceral adipose tissue in men (R2 = .44, P = .0051). Fasting insulin and fat-free mass, with minus sign, and both visceral and subcutaneous adipose tissue were the predictors of the TEF (R2 = .25, P = .0055) in premenopausal women. This study demonstrates that visceral fat distribution is important in determining the RMR in postmenopausal women and men. In premenopausal women, total adipose tissue is a main determinant of both the RMR and TEF This last effect could be counterbalanced by insulin resistance.

Assessment of protein energy malnutrition in older persons, part I: History, examination, body composition, and screening tools

Protein-energy malnutrition is a prevalent problem in older persons. Its relation to increased morbidity and mortality has been well documented. Early recognition of malnutrition allows for a timely intervention. A large proportion of chronic diseases affecting older persons can be either prevented or significantly improved by improving nutrition, which underscores the importance of developing a screening system that can trigger a more comprehensive evaluation when indicated. Screening for malnutrition in older persons can be difficult because of the normal age-related changes in many of the commonly used parameters. A comprehensive nutritional evaluation includes a complete history and physical examination in addition to a more specific nutrition-oriented assessment. Specific nutritional assessment includes estimating food intake, anthropometric measurements, and evaluation of several biochemical parameters commonly affected by changes in nutritional status. In this article, we review the commonly used tools for nutritional assessment in older persons. The goal is to promote disease-free, active, and successful aging.

Special considerations in design of trials with elderly subjects: unexplained weight loss, body composition and energy expenditure

Wasting and cachexia are significant problems in the elderly that increase mortality and morbidity. It is presently unclear as to the physiological mechanism underlying unexplained weight loss. We examine heart failure as a physiological model to demonstrate the importance of measuring several physiological outcome variables that have increased our understanding of wasting and cachexia in the elderly. These include the assessment of: energy expenditure, body composition, physical activity and exercise tolerance. We review recent data that has assessed energy expenditure in free-living heart failure patients using stable isotope methodology (doubly labeled water). Preliminary results show low levels of daily energy expenditure in heart failure patients due to extremely low levels of physical activity. Thus, a "hypermetabolic state" in free-living heart failure patients is not supported by these findings. The low level of physical activity is likely a consequence of their reduced exercise capacity and contributes to their skeletal muscle atrophy. This concept is support by the relationship between peak VO2 and muscle mass (r = 0.92; P < 0.01), as measured from dual energy x-ray absorptiometry. An understanding of the physiological factors influencing energy dysregulation and low exercise capacity may help guide future therapeutic interventions to restore energy balance and increase functional independence in patients with chronic heart failure.

Serum leptin and longevity

There are changes in the ability to regulate energy balance and caloric intake with aging. Consequently, we investigated whether human aging modifies the levels of serum leptin, a novel hormone implicated in the regulation of energy balance. We studied 268 Caucasian men and women aged 22-85 years, and divided them into groups with mean ages of 30, 40, 50, 65, 75, 80 and 85 years. Fasting serum leptin concentrations were determined by radioimmunoassay. Subjects aged 65 or older were followed for five years after the blood sampling. There were no statistically significant differences in fasting serum leptin concentrations across different age groups in females (p = 0.090). Fasting serum leptin concentrations were also similar in different age groups in males, except that males in the 30-year age group had lower serum leptin levels than males in the 75-year age group (p = 0.042). Leptin levels were 2-3 fold higher in females than in males in each age group (p < 0.005 except p = 0.063 in the 75-year age group). Elderly women, who lived longer, had 47% higher (p < 0.05) serum leptin concentrations, and 17% higher (p < 0.001) BMI than the women who died within five years of blood sampling. Leptin levels were not statistically different in these women after adjusting for BMI. Thus, aging has no apparent effect on serum leptin levels in women or men, and the gender differences in leptin is present also in the older age groups. Higher leptin concentrations in the females who live longer may reflect a better nutritional status, and a greater adipose tissue mass rather than a primary factor for survival.