The Effect of Low-Volume High-Intensity Interval Training on Body Composition and Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence for the efficacy of low-volume high-intensity interval training (HIIT) for the modulation of body composition is unclear.

OBJECTIVES

We examined the effect of low-volume HIIT versus a non-exercising control and moderate-intensity continuous training (MICT) on body composition and cardiorespiratory fitness in normal weight, overweight and obese adults. We evaluated the impact of low-volume HIIT (HIIT interventions where the total amount of exercise performed during training was ≤ 500 metabolic equivalent minutes per week [MET-min/week]) compared to a non-exercising control and MICT.

METHODS

A database search was conducted in PubMed (MEDLINE), EMBASE, CINAHL, Web of Science, SPORTDiscus and Scopus from the earliest record to June 2019 for studies (randomised controlled trials and non-randomised controlled trials) with exercise training interventions with a minimum 4-week duration. Meta-analyses were conducted for between-group (low-volume HIIT vs. non-exercising control and low-volume HIIT vs. MICT) comparisons for change in total body fat mass (kg), body fat percentage (%), lean body mass (kg) and cardiorespiratory fitness.

RESULTS

From 11,485 relevant records, 47 studies were included. No difference was found between low-volume HIIT and a non-exercising control on total body fat mass (kg) (effect size [ES]: - 0.129, 95% confidence interval [CI] - 0.468 to 0.210; p = 0.455), body fat (%) (ES: - 0.063, 95% CI - 0.383 to 0.257; p = 0.700) and lean body mass (kg) (ES: 0.050, 95% CI - 0.250 to 0.351; p = 0.744), or between low-volume HIIT and MICT on total body fat mass (kg) (ES: - 0.021, 95% CI - 0.272 to 0.231; p = 0.872), body fat (%) (ES: 0.005, 95% CI - 0.294 to 0.304; p = 0.974) and lean body mass (kg) (ES: 0.030, 95% CI - 0.167 to 0.266; p = 0.768). However, low-volume HIIT significantly improved cardiorespiratory fitness compared with a non-exercising control (p < 0.001) and MICT (p = 0.017).

CONCLUSION

These data suggest that low-volume HIIT is inefficient for the modulation of total body fat mass or total body fat percentage in comparison with a non-exercise control and MICT. A novel finding of our meta-analysis was that there appears to be no significant effect of low-volume HIIT on lean body mass when compared with a non-exercising control, and while most studies tended to favour improvement in lean body mass with low-volume HIIT versus MICT, this was not significant. However, despite its lower training volume, low-volume HIIT induces greater improvements in cardiorespiratory fitness than a non-exercising control and MICT in normal weight, overweight and obese adults. Low-volume HIIT, therefore, appears to be a time-efficient treatment for increasing fitness, but not for the improvement of body composition.

Home-based Aerobic Exercise and Resistance Training in Peritoneal Dialysis Patients: A Randomized Controlled Trial

Potential effects of aerobic and resistance training in peritoneal dialysis (PD) patients have been partially elucidated. We investigated effects of a home-based exercise program on physical functioning and health-related quality of life (HRQOL) in PD patients. Patients were randomly assigned to exercise (n = 24) and usual care (n = 23) groups. The exercise patients performed aerobic exercise thrice weekly and resistance training twice weekly at home for 12 weeks. The usual care patients received no specific intervention. The distance in incremental shuttle walking test significantly improved in the exercise group compared with the usual care group (P = 0.02). Among the HRQOL subscales assessed using the Kidney Disease Quality of Life-Short Form questionnaire, kidney disease component summary (P = 0.03), physical role functioning (P = 0.01), emotional role functioning (P < 0.01), and role/social component summary (P < 0.01) significantly improved in the exercise group. Moreover, serum albumin was significantly maintained in the exercise group (P = 0.03). There were no reported adverse events associated with the intervention. To our knowledge, this is the first randomized controlled trial to indicate the beneficial effects of a 12-week home-based exercise program exclusively in PD patients.

Exercise Capacity and Association with Quality of Life in Peritoneal Dialysis Patients

BACKGROUND

Muscle wasting, common and progressive in uremic patients, is associated with a high probability for morbidity, lower health-related quality of life (HRQOL), and mortality. However, exercise tolerance in peritoneal dialysis (PD) patients has not been fully elucidated. The aim of this study was to evaluate exercise capacity, its determinants, and its association with HRQOL in PD patients.

METHODS

Outpatients treated with PD at Keio University Hospital from December 2016 to March 2018 were included in this single-center cross-sectional observational study. Exercise capacity was assessed by incremental shuttle walking test (ISWT) and handgrip and quadriceps strength. In addition to evaluation of PD-related parameters, HRQOL was assessed by the Kidney Disease Quality of Life-Short Form questionnaire.

RESULTS

Among the 50 recruited PD outpatients, age and PD vintage were 63.8 ± 9.6 and 3.8 ± 2.8 years, respectively. Physical examination revealed ISWT of 312.0 ± 138.2 m, handgrip strength of 27.5 ± 6.9 kg, and quadriceps strength of 23.3 ± 10.0 kg. Multivariate analysis showed that younger age and male sex were significantly associated with higher ISWT and handgrip and quadriceps strength. Skeletal mass index (SMI) remained a significant predictor of handgrip and quadriceps strength. Moreover, only ISWT was strongly correlated with higher HRQOL scores, including physical, mental, and kidney-specific domains, even after adjustment for age and sex.

CONCLUSIONS

Exercise tolerance in PD patients was partially determined by age, sex, and SMI. Moreover, this is the first study to demonstrate the strong relationship between aerobic capacity and HRQOL in PD patients.

Nutrition imbalance in Chinese chronic kidney disease children

BACKGROUND

Nutrition imbalance is common in chronic kidney disease (CKD) children. This study evaluated the nutrition status of CKD children at different stages using bioimpedance analysis (BIA) compared with anthropometry.

METHODS

Fifty-five CKD children at stages III, IV, V and 19 age- and sex-matched healthy controls were recruited. Fat, protein and mineral composition on BIA were analyzed together with anthropometry for height, weight and body mass index (BMI). Biochemistry was also checked in CKD children.

RESULTS

Of the CKD children, 23.6%, 10.9% and 56.3% were underweight, overweight/obese and stunted, respectively. On BIA, 52.7%, 70.9%, 14.5% and 40.0% of the CKD children had protein reduction, fat reduction, fat enhancement and mineral reduction, respectively. Growth retardation and nutrition reduction became remarkable at stages IV and V. Approximately 65% of healthy-weight children had nutrition reduction. In the underweight and healthy-weight groups, fat reduction rates were higher than protein reduction rate. In the overweight/obese group, fat enhancement was most notable. Mineral reduction was less remarkable.

CONCLUSIONS

The nutrition imbalance in CKD children on BIA correlated well with anthropometry and disease process, supporting BIA as an auxiliary diagnosis tool.

A snapshot of the nutritional status of Crohn's disease among adolescents in Brazil: a prospective cross-sectional study

BACKGROUND

The relationship between nutrition and Crohn's disease (CD) is complex and involves several therapeutic possibilities including: nutrition treatment for malnourished patients, optimization of growth and development, prevention of osteoporosis, first-line therapy for active disease, and maintenance of disease remission. In children and adolescents with CD, malnutrition is a common problem that adversely affects the prognosis. In at-risk adolescent CD patients, it is important to assess body composition, food intake, energy expenditure, nutrient balance and serum levels of nutrients before planning interventions for this population. The aim of this study was to provide a snapshot of the nutritional status of adolescents with CD in Brazil.

METHODS

We prospectively selected 22 patients with mildly to moderately active CD, 29 patients with inactive CD and 35 controls (first-degree relatives of and in the same age bracket as the CD patients). The age range of participants was between 13.2 and 19.4 years old. We collected anthropometric data including weight, height, and body mass index (BMI), which were expressed as Z scores: weight-for-age, height-for-age and BMI-for-age, respectively, as well as using bioimpedance to determine body composition and assessing the Tanner stage. We also assessed macronutrients and micronutrients (serum levels and dietary intake of both). We used the chi-square test to determine whether any of the studied variables were associated with inactive or active CD. The level of significance was set at 5 % (p < 0.05). We have written informed parental consent for participation for any minors and written informed consent for any participants that were adults.

RESULTS

The mean values for lean body mass, Tanner stage, height-for-age Z score and BMI-for-age Z score were lower in the active CD group than in the inactive CD and control groups (p < 0.05 for both). Compared with the controls, the CD patients showed significant differences in terms of the quality of dietary intake (particularly in caloric intake, dietary protein intake, dietary fiber intake, and micronutrient intake), which were reflected in the serum levels of nutrients, mainly vitamins A and E (p < 0.05).

CONCLUSIONS

Adolescents with CD (including those with mildly to moderately active or inactive disease) have a nutritional risk, which makes it important to conduct nutritional assessments in such patients.

Hydration Status of Patients Dialyzed with Biocompatible Peritoneal Dialysis Fluids

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BACKGROUND

Biocompatible fluids for peritoneal dialysis (PD) have been introduced to improve dialysis and patient outcome in end-stage renal disease. However, their impact on hydration status (HS), residual renal function (RRF), and dialysis adequacy has been a matter of debate. The aim of the study was to evaluate the influence of a biocompatible dialysis fluid on the HS of prevalent PD patients. ♦

METHODS

The study population consisted of 18 prevalent PD subjects, treated with standard dialysis fluids. At baseline, 9 patients were switched to a biocompatible solution, low in glucose degradation products (GDPs) (Balance; Fresenius Medical Care, Bad Homburg, Germany). Hydration status was assessed through clinical evaluation, laboratory parameters, echocardiography, and bioimpedance spectroscopy over a 24-month observation period. ♦

RESULTS

During the study period, urine volume decreased similarly in both groups. At the end of the evaluation, there were also no differences in clinical (body weight, edema, blood pressure), laboratory (N-terminal pro-brain natriuretic peptide, NTproBNP), or echocardiography determinants of HS. However, dialysis ultrafiltration decreased in the low-GDP group and, at the end of the study, equaled 929 ± 404 mL, compared with 1,317 ± 363 mL in the standard-fluid subjects (p = 0.06). Hydration status assessed by bioimpedance spectroscopy was +3.64 ± 2.08 L in the low-GDP patients and +1.47 ± 1.61 L in the controls (p = 0.03). ♦

CONCLUSIONS

The use of a low-GDP biocompatible dialysis fluid was associated with a tendency to overhydration, probably due to diminished ultrafiltration in prevalent PD patients.

Evaluating Hyponatremia in Non-Diabetic Uremic Patients on Peritoneal Dialysis

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BACKGROUND

An approach to hyponatremia in uremic patients on peritoneal dialysis (PD) necessitates the assessment of intracellular fluid volume (ICV) and extracellular volume (ECV). The aim of the study was to evaluate the association of plasma sodium (Na(+)) concentration and body fluid composition and identify the causes of hyponatremia in non-diabetic PD patients. ♦

METHODS

Sixty non-diabetic uremic patients on PD were enrolled. Baseline body fluid composition, biochemistry, hand-grip test, peritoneal membrane characteristics, dialysis adequacy, Na(+) and water balance, and residual renal function (RRF) were measured. These parameters were reevaluated for those who developed hyponatremia, defined as serum Na(+) concentration < 132 mmol/L and a decline in serum Na(+) > 7 mmol/L, during monthly visits for 1 year. Body fluid composition was determined by multi-frequency bioelectrical impedance (BIA). ♦

RESULTS

There was no significant correlation between serum Na(+) concentrations and any other parameters except a negative correction with overnight ultrafiltration (UF) amount (p = 0.02). The ICV/ECV ratio was positively correlated with serum albumin (p < 0.005) and hand grip strength (p < 0.05). Over 1 year, 9 patients (M:F = 3:6, aged 35 - 77) with 4 different etiologies of hyponatremia were identified. Hyponatremic patients with a body weight (BW) loss had either an increased ICV/ECV ratio associated with primarily a negative Na(+) balance (n = 2) or a reduced ratio of ICV/ECV associated with malnutrition (n = 2). In contrast, hyponatremic patients with a BW gain had either a reduced ICV/ECV ratio associated with a rapid loss of RRF and a higher peritoneal permeability (n = 2) or a normal to increased ICV/ECV ratio associated with high water intake (n = 3). ♦

CONCLUSION

Besides BW change and ultrafiltration rate, the assessment of ICV/ECV ratio is valuable in identifying the etiologies of hyponatremia in PD and provides a guide for optimal therapy.

Nutrition Monitoring in the PICU

The ideal set of variables for nutritional monitoring that may correlate with patient outcomes has not been identified. This is particularly difficult in the PICU patient because many of the standard modes of nutritional monitoring, although well described and available, are fraught with difficulties. Thus, repeated anthropometric and laboratory markers must be jointly analyzed but individually interpreted according to disease and metabolic changes, in order to modify and monitor the nutritional treatment. In addition, isotope techniques are neither clinically feasible nor compatible with the multiple measurements needed to follow progression. On the other hand, indirect alternatives exist but may have pitfalls, of which the clinician must be aware. Risks exist for both overfeeding and underfeeding of PICU patients so that an accurate monitoring of energy expenditure, using targeted indirect calorimetry, is necessary to avoid either extreme. This is very important, since the monitoring of the nutritional status of the critically ill child serves as a guide to early and effective nutritional intervention.

Body composition and depressive/anxiety symptoms in overweight and obese individuals with metabolic syndrome

BACKGROUND

Several studies point to a correlation between obesity and the severity of depressive and anxiety symptoms in children and adults, but there are still some controversial points about this association. The aim of this study is to investigate the relationship between body composition and the severity of anxiety/depressive symptoms in overweight and obese individuals with Metabolic Syndrome (MS).

METHODS

Fifty patients, 18-50 years old, overweight or obese and with the diagnosis of MS based on the International Diabetes Federation (IDF) criteria were selected for this study. Body composition was evaluated using Dual Energy X-ray Absorptiometry (DXA). Depressive symptoms were evaluated using the Hospital Anxiety and Depression Scale (HADS-Depression) and the Beck Depression Inventory (BDI). Anxiety symptoms were evaluated using HADS-Anxiety.

RESULTS

No correlation was found between depressive symptoms (HADS-Depression or BDI) and Body Mass Index (BMI) (r = 0.01; p = 0.94 and r = -0.12, p = 0.38; respectively), Waist Circumference (WC) (r = -0.06, p = 0.67 and r = -0.22, p = 0.12; respectively), and Waist-to-Hip Ratio (WHR) (r = -0.12, p = 0.40 and r = -0.17, p = 0.23; respectively). Additionally, no correlation was found among anxiety symptoms (HADS-Anxiety) and BMI (r = -0.15, p = 0.27), and WHR (r = -0.17, p = 0.24). In contrast, a significant correlation was found between percentage of total fat (DXA) and HADS-Depression (r = 0.34, p = 0.019) and HADS-Anxiety (r = 0.30, p = 0.039). Additionally, an inverse and strong correlation was found between lean mass (in grams) and HADS-Depression (r = -0.42, p = 0.004), HADS anxiety (r = -0.57, p < 0.0001), and BDI (r = -0.44, p = 0.026).

CONCLUSIONS

In individuals with MS, the percentage of body fat, and not central fat, BMI, WC, or WHR, was associated with an increased severity of anxiety and depressive symptoms. In contrast, total lean mass was strongly associated with fewer anxiety/depressive symptoms, suggesting that body composition might be related to psychiatric comorbidity in overweight individuals with MS.

The effects of exercise training in addition to energy restriction on functional capacities and body composition in obese adults during weight loss: a systematic review

BACKGROUND

Obesity is associated with impairments of physical function, cardiovascular fitness, muscle strength and the capacity to perform activities of daily living. This review examines the specific effects of exercise training in relation to body composition and physical function demonstrated by changes in cardiovascular fitness, and muscle strength when obese adults undergo energy restriction.

METHODS

Electronic databases were searched for randomised controlled trials comparing energy restriction plus exercise training to energy restriction alone. Studies published to May 2013 were included if they used multi-component methods for analysing body composition and assessed measures of fitness in obese adults.

RESULTS

Fourteen RCTs met the inclusion criteria. Heterogeneity of study characteristics prevented meta-analysis. Energy restriction plus exercise training was more effective than energy restriction alone for improving cardiovascular fitness, muscle strength, and increasing fat mass loss and preserving lean body mass, depending on the type of exercise training.

CONCLUSION

Adding exercise training to energy restriction for obese middle-aged and older individuals results in favourable changes to fitness and body composition. Whilst weight loss should be encouraged for obese individuals, exercise training should be included in lifestyle interventions as it offers additional benefits.

Precision errors, least significant change, and monitoring time interval in pediatric measurements of bone mineral density, body composition, and mechanostat parameters by GE lunar prodigy

Dual-energy X-ray absorptiometry (DXA) method is widely used in pediatrics in the study of bone density and body composition. However, there is a limit to how precise DXA can estimate bone and body composition measures in children. The study was aimed to (1) evaluate precision errors for bone mineral density, bone mass and bone area, body composition, and mechanostat parameters, (2) assess the relationships between precision errors and anthropometric parameters, and (3) calculate a "least significant change" and "monitoring time interval" values for DXA measures in children of wide age range (5-18yr) using GE Lunar Prodigy densitometer. It is observed that absolute precision error values were different for thin and standard technical modes of DXA measures and depended on age, body weight, and height. In contrast, relative precision error values expressed in percentages were similar for thin and standard modes (except total body bone mineral density [TBBMD]) and were not related to anthropometric variables (except TBBMD). Concluding, due to stability of percentage coefficient of variation values in wide range of age, the use of precision error expressed in percentages, instead of absolute error, appeared as convenient in pediatric population.

Change in body composition in accordance with residual renal function in patients on peritoneal dialysis

OBJECTIVES

The aim of this study is to evaluate changes in body composition in accordance with residual renal function (RRF).

SUBJECTS AND METHODS

Two hundred forty-four patients with more than 1 year of follow-up were enrolled. The mean value of RRF at peritoneal dialysis (PD) initiation and 1 year after PD initiation was used as an indicator of the time-averaged RRF (TA-RRF). The patients were divided into 3 groups with respect to the tertile of the TA-RRF level: low tertile (n = 81), middle tertile (n = 82), and high tertile (n = 81). Body composition measurement was determined from dual-energy X-ray absorptiometry and bioimpedance analysis. This analysis was performed at PD initiation and 1 year after PD initiation.

RESULTS

Multivariate analysis showed that the high TA-RRF tertile was associated with an increase in lean mass index. Fat mass index in all tertiles and bone mineral content index in the middle and high TA-RRF tertiles were increased, but no significant difference were observed in these changes among the 3 tertiles. The edema index decreased over the 1-year PD period. The high TA-RRF tertile was associated with a lower edema index. Although there was no statistical significance, the increase in fat mass/lean mass ratio (FM/LM) attenuated as the grade of TA-RRF tertile increased. The increase in fat mass index was similar to the trend in FM/LM.

CONCLUSION

TA-RRF was associated with an increase in total lean mass and a decrease in edema index.

Geriatric Nutritional Risk Index as a prognostic factor in peritoneal dialysis patients

BACKGROUND

The Geriatric Nutritional Risk Index (GNRI) might be a useful screening tool for malnutrition in dialysis patients. However, data concerning the GNRI as a prognostic factor in peritoneal dialysis (PD) patients are scarce.

METHODS

We reviewed the medical records at Yeungnam University Hospital in Korea to identify all adults (>18 years) who received PD; 486 patients were enrolled in the study.

RESULTS

The initial low, middle, and high GNRI tertiles included 162, 166, and 158 patients respectively. Significant correlations were noted between the initial GNRI and body mass index, creatinine, albumin, arm circumference, fat mass index, and comorbidities. The cut-off value for the time-averaged GNRI over 1 year was 96.4, and the sensitivity and specificity for a diagnosis of a decline in lean mass were 77.1% and 40.0% respectively. A multivariate analysis adjusted for age, risk according to the Davies comorbidity index, and C-reactive protein showed that an low initial GNRI tertile was associated with mortality in PD patients.

CONCLUSIONS

The GNRI is a simple method for predicting nutrition status and clinical outcome in PD patients.

Assessment of fluid status in CAPD patients using the body composition monitor

AIMS AND OBJECTIVES

To assess the degree of overhydration in our peritoneal dialysis patients and to examine the factors contributing to overhydration.

BACKGROUND

Volume control is critical for the success of peritoneal dialysis, but dry weight has been difficult to ascertain accurately. Chronic fluid overload and hypertension are among the leading causes of mortality in dialysis patients.

DESIGN

A cross-sectional observational study.

METHODS

The body composition monitor (Fresenius Medical Care, Bad Homburg, Germany) is a bioimpedance spectroscopy device that has been validated for the assessment of overhydration. We used this body composition monitor device on all patients on continuous ambulatory peritoneal dialysis at our institution who met the inclusion criteria to assess their degree of overhydration.

RESULTS

Thirty four (17 men, 17 women; mean age 44·5 ± 14·2 years) of a 45 continuous ambulatory peritoneal dialysis patients were enrolled. The mean overhydration was 2·4 ± 2·4 l. Fifty per cent of the patients were ≥2 l overhydrated. Overhydration correlated with male gender, low serum albumin, increasing number of antihypertensive agents and duration of dialysis. There was no difference in overhydration between diabetic and non-diabetic patients. Men were more overhydrated than women, had lower Kt/V and were older. Although, there was no difference in blood pressure between the genders, men had a trend towards a higher usage of antihypertensive agents.

CONCLUSION

Our study demonstrates that overhydration is common in peritoneal dialysis patients. Blood pressure should ideally be controlled with adherence to dry weight and low salt intake rather than adding antihypertensive agents even in the absence of clinical oedema.

RELEVANCE TO CLINICAL PRACTICE

Body composition monitor is a simple, reliable and inexpensive tool that can be routinely used in the outpatient clinic setting or home visit to adjust the dry weight and avoid chronic fluid overload in between nephrologists review.

A study of the clinical and biochemical profile of peritoneal dialysis fluid low in glucose degradation products

OBJECTIVE

Although peritoneal dialysis (PD) is a widely accepted form of renal replacement therapy, concerns remain regarding the bioincompatible nature of standard PD fluid (PDF). Short-term studies of new biocompatible PDFs low in glucose degradation products (GDPs) reveal divergent results with respect to peritoneal integrity.

METHODS

We studied 125 patients on maintenance PD who were assigned, by simple randomization, to receive either conventional or low-GDP PDF at PD initiation. Parameters of dialysis adequacy and peritoneal transport of small solutes were determined at initiation and after a period of maintenance PD at the time when serum and overnight effluent dialysate were simultaneously collected and assayed for various cytokines, chemokines, adipokines, and cardiac biomarkers. All patients were further followed prospectively for an average of 15 months from the day of serum and effluent collection to determine patient survival and cardiovascular events.

RESULTS

Patients treated with conventional or low-GDP PDF were matched for sex, age, duration of dialysis, dialysis adequacy, and incidence of cardiovascular disease or diabetes. After an average of 2.3 years of PD treatment, the weekly total and peritoneal creatinine clearance, and the total and peritoneal Kt/V were comparable in the groups. However, urine output was higher in patients using low-GDP PDF despite there having been no difference between the groups at PD initiation. Patients using low-GDP PDF also experienced a slower rate of decline of residual glomerular filtration and urine output than did patients on conventional PDF. Compared with serum concentrations, effluent concentrations of tumor necrosis factor α, hepatocyte growth factor, macrophage migration inhibitory factor, interleukins 8 and 6, C-reactive protein, and leptin were found to be higher in both groups of patients after long-term PD, suggesting that the peritoneal cavity was the major source of those mediators. Compared with patients on low-GDP PDF, patients on conventional fluid showed elevated leptin and reduced adiponectin levels in serum and effluent. The effluent concentration of interleukin 8 was significantly lower in patients using low-GDP PDF. The survival rate and incidence of cardiovascular complications did not differ between these groups after maintenance PD for an average of 3.6 years.

CONCLUSIONS

It appears that low-GDP PDF results in an improvement of local peritoneal homeostasis through a reduction of chronic inflammatory status in the peritoneum.

Validation of longitudinal DXA changes in body composition from pre- to mid-adolescence using MRI as reference

Dual-energy X-ray absorptiometry (DXA) has been used extensively for bone mineral density and body composition assessments. Surprisingly, the role of DXA in monitoring changes in children's body composition, using direct imaging methods such as magnetic resonance imaging (MRI) as reference, is still yet to be validated. We aimed at validating the use of DXA in monitoring change in the thigh lean soft tissue mass (LSTM) and fat mass (FM) when compared with thigh skeletal muscle mass (SM) and FM, measured using MRI as the reference standard, from childhood to midadolescence. At baseline, 22 healthy children (16 boys and 6 girls) aged 8-11yr were included, and then recalled at pubertal stage Tanner2-Tanner4. LSTM-DXA and FM-DXA of the mid-third femur and SM-MRI and FM-MRI of the same region were measured on the same day. The same protocol was repeated 26-48mo later. At baseline, DXA overestimated LSTM-DXA on average by 222g (95% confidence interval [CI]: 33-410g) with a concordance C-LSTM=0.576. FM-MRI and FM-DXA were not significantly different (95% CI=213 to 199g, the C-FM=0.907). At follow-up, change in LSTM-DXA and FM-DXA were not significantly different to change in SM-MRI and FM-MRI, respectively (95% CI of the difference was -278 to 208g for LSTM, and -148 to 236g for FM). The coefficient of concordance between the 2 techniques was 0.88 for both LSTM and FM. This study validates the use of DXA in monitoring changes in LSTM and FM in children, confirming its significant potential in clinical and research roles in pediatric body composition.

Fluid status in peritoneal dialysis patients: the European Body Composition Monitoring (EuroBCM) study cohort

BACKGROUND

Euvolemia is an important adequacy parameter in peritoneal dialysis (PD) patients. However, accurate tools to evaluate volume status in clinical practice and data on volume status in PD patients as compared to healthy population, and the associated factors, have not been available so far.

METHODS

We used a bio-impedance spectroscopy device, the Body Composition Monitor (BCM) to assess volume status in a cross-sectional cohort of prevalent PD patients in different European countries. The results were compared to an age and gender matched healthy population.

RESULTS

Only 40% out of 639 patients from 28 centres in 6 countries were normovolemic. Severe fluid overload was present in 25.2%. There was a wide scatter in the relation between blood pressure and volume status. In a multivariate analysis in the subgroup of patients from countries with unrestricted availability of all PD modalities and fluid types, older age, male gender, lower serum albumin, lower BMI, diabetes, higher systolic blood pressure, and use of at least one exchange per day with the highest hypertonic glucose were associated with higher relative tissue hydration. Neither urinary output nor ultrafiltration, PD fluid type or PD modality were retained in the model (total R² of the model = 0.57).

CONCLUSIONS

The EuroBCM study demonstrates some interesting issues regarding volume status in PD. As in HD patients, hypervolemia is a frequent condition in PD patients and blood pressure can be a misleading clinical tool to evaluate volume status. To monitor fluid balance, not only fluid output but also dietary input should be considered. Close monitoring of volume status, a correct dialysis prescription adapted to the needs of the patient and dietary measures seem to be warranted to avoid hypervolemia.

Sarcopenia: etiology, clinical consequences, intervention, and assessment

The aging process is associated with loss of muscle mass and strength and decline in physical functioning. The term sarcopenia is primarily defined as low level of muscle mass resulting from age-related muscle loss, but its definition is often broadened to include the underlying cellular processes involved in skeletal muscle loss as well as their clinical manifestations. The underlying cellular changes involve weakening of factors promoting muscle anabolism and increased expression of inflammatory factors and other agents which contribute to skeletal muscle catabolism. At the cellular level, these molecular processes are manifested in a loss of muscle fiber cross-sectional area, loss of innervation, and adaptive changes in the proportions of slow and fast motor units in muscle tissue. Ultimately, these alterations translate to bulk changes in muscle mass, strength, and function which lead to reduced physical performance, disability, increased risk of fall-related injury, and, often, frailty. In this review, we summarize current understanding of the mechanisms underlying sarcopenia and age-related changes in muscle tissue morphology and function. We also discuss the resulting long-term outcomes in terms of loss of function, which causes increased risk of musculoskeletal injuries and other morbidities, leading to frailty and loss of independence.

Assessment and Monitoring of Nutrition Status in Pediatric Peritoneal Dialysis Patients

Abnormalities of nutrition status are a common problem in children on peritoneal dialysis (PD) and a source of significant morbidity and mortality. The state of decreased body protein mass and fuel reserves (body protein and fat mass) common in PD patients is now better known as protein–energy wasting (PEW).

Protein–energy wasting is a slow, progressive process in chronic kidney disease. The correct approach to this problem includes measurement of early, intermediate, and late markers of PEW, and consideration of the risk factors specific to the patient and to PD.

The earliest markers of PEW are associated with some symptoms observed clinically: a decrease in dietary intake and an increase in inflammatory markers. The second stage in the development of PEW (patients with established PEW) is characterized by abnormalities in numerous markers: bioimpedance analysis (BIA) and anthropometric indices, other indices of body mass and composition, biochemical parameters, and indices of protein, glucose, and lipid metabolism. When PEW is established, clear clinical signs become evident: patients in this stage are characterized by high rates of hospitalization and an increased risk for morbidity and mortality as compared with patients without cachexia.

Risk factors for PEW can already be present in an apparently well-nourished child who initiates PD: glucose absorption from PD fluid, abdominal distension from PD volume, gastroesophageal reflux, and even more importantly, inadequate dialysis dose in relation to decline in residual renal function.

Given the complexity of the pathogenesis and clinical picture of PEW, no single measure, but rather panels of nutritional measures are necessary to diagnose the condition. Combined nutrition scores such as the anthropometry–BIA nutrition score may add value to the monitoring of nutrition status in children on PD.