Assess Changes In Body Composition Research Articles

Bioelectrical Impedance Vector Analysis, Nutritional Ultrasound®, and Handgrip Strength as Innovative Methods for Monitoring Critical Anorexia Nervosa Physical Recovery: A Pilot Study.

Eating disorders (EDs) manifest as persistent disruptions in eating habits or related behaviors, significantly impacting physical health and psychosocial well-being. Nutritional assessment in ED patients is crucial for monitoring treatment efficacy. While dual-energy X-ray absorptiometry (DEXA) remains standard, interest in alternative methods such as bioelectrical impedance vector analysis (BIVA) and Nutritional Ultrasound® (NU) has risen due to their affordability and portability. Additionally, hand dynamometry offers a user-friendly approach to assessing grip strength (HGS), indicative of nutritional status. A prospective study was carried out to evaluate the utility of BIVA, NU®, and HGS in 43 female AN patients. Measurements were taken at baseline and hospital discharge. A total of 41 patients completed the study. After the intervention, numerous BIVA-related parameters such as fat (3.5 ± 2 kg vs. 5.3 ± 2.7 kg, p < 0.001) and free fat mass (33.9 ± 3.8 kg vs. 37.5 ± 4.1 kg, p < 0.001) were partially restored. Similarly, Nutritional Ultrasound® showed promising results in assessing body composition changes such as total abdominal fat tissue (0.5 ± 0.3 cm vs. 0.9 ± 0.3 cm, p < 0.05). In the same way, rectus femoris cross-sectional area values correlated with clinical outcomes such as free fat mass (0.883, p < 0.05) and appendicular muscle mass (0.965, p < 0.001). HGS reached the normality percentile after the intervention (21.6 ± 9.1 kg vs. 25.9 ± 12.3 kg, p < 0.05), demonstrating a significant association between grip strength and body composition parameters such as free fat mass (0.658, p < 0.001) and appendicular muscle mass (0.482, p < 0.001). Incorporating BIVA-, NU®-, and HGS-enhanced nutritional assessment into the treatment of AN patients offers cost-effective, portable, and non-invasive alternatives to DEXA. These techniques offer valuable insights into changes in body composition and nutritional status, which, in turn, facilitate treatment monitoring and contribute to improved patient outcomes.

The Influence of Endurance Training on the Lipid Profile, Body Mass Composition and Cardiovascular Efficiency in Middle-Aged Cross-Country Skiers.

Monitoring the training of amateur long-distance cross-country skiers (XCS) can help athletes’ achieve a higher exercise capacity and protect their health. The aim of this study was to assess body composition changes and lipid profiles in middle-aged amateur long-distance XCS after four months of training, including specialized roller ski training. The results of the time-to-exhaustion (TTE) test and blood tests and changes in body composition were analyzed with basic descriptive statistics: the paired Wilcoxon test was used to compare the results (initial and final). Spearman’s rank correlation coefficient (R) was used to assess the influence of various variables on maximum oxygen uptake (VO2max). The findings show that training of amateur long-distance XCS improved maximal oxygen uptake (p = 0.008) and had a positive effect on fat reduction, measured in percentages (p = 0.038) and in kilograms (p = 0.023), but did not change blood lipids or other parameters. Further research could focus on other aspects of the annual training cycle: the competition period, and women in a larger group of athletes. Training with roller skis and a cross-country skiing training machine (a specialized machine for strengthening the arms and upper body) can support health and prevent obesity, overweight, and cardiovascular disease.

ASO Visual Abstract: Nutritional Outcomes of Thoracic Duct Resection for Radical Esophagectomy by Assessment of Body Composition Changes in 1 Year: A Single-Center Retrospective Study

ASO Visual Abstract: Nutritional Outcomes of Thoracic Duct Resection for Radical Esophagectomy by Assessment of Body Composition Changes in 1 Year: A Single-Center Retrospective Study

Nutritional Outcomes of Thoracic Duct Resection for Radical Esophagectomy by Assessing Body Composition Changes in One Year: A Single-Center Retrospective Study.

Thoracic duct (TD) resection is performed when the tumor or a metastatic lymph node directly invades the TD, and is sometimes indicated for radical lymphadenectomy during esophagectomy in esophageal cancer patients. However, the effect of TD resection on nutritional status has not been established. In total, 174 consecutive patients from October 2015 to March 2019 who underwent radical esophagectomy for esophageal cancer in Toranomon Hospital were classified into thoracic duct preserved group (n = 51) and TD-resected (TD-R) group (n = 123). We compared laboratory data, body composition data from bioelectrical impedance analysis measured preoperatively and at 1 and 12months after surgery, and postoperative complications between the two groups. Clinical stage was significantly more advanced in the TD-R group. Total body weight, body mass index, and fat mass continuously decreased in the two groups over 12months after surgery, and the decreases were statistically greater in the TD-R group at 12months after surgery. Skeletal muscle mass and fat-free mass decreased over 1month after surgery and stayed in a reduced state until 12months after surgery without statistically significant differences between the two groups. TD resection did not increase incidence of postoperative complications (Clavien-Dindo classification ≥ grade III), but TD resection increased incidence of chylothorax. Our results suggest that loss of body fat mass, which was a main contributor to body weight loss, was accelerated in the TD-R group, but TD resection does not deteriorate loss of muscle mass at 12months after surgery.

Rapid decline in visceral adipose tissue over 1 month is associated with poor prognosis in patients with unresectable pancreatic cancer.

BackgroundInvoluntary weight loss related to cachexia is common in patients with advanced cancer, but the association between body composition changes and survival is still unclear in pancreatic cancer.MethodsWe retrospectively reviewed the clinical outcomes of 55 patients with advanced pancreatic cancer undergoing palliative therapy or best supportive care (BSC). The skeletal muscle index (SMI), visceral adipose tissue index (VATI), subcutaneous adipose tissue index (SATI), and visceral to subcutaneous adipose tissue area ratio (VSR) were calculated based on the cross‐sectional area on two sets of computed tomography images obtained at cancer diagnosis and 1 month later before treatment. The prognostic value of body composition indexes at diagnosis and the changes in those indexes over 1 month was then evaluated.ResultsIn total, 45 patients (81.8%) received chemotherapy, chemoradiation, or radiation therapy, whereas the remaining patients underwent BSC. There were 27 patients (49.1%) who had low SMI at cancer diagnosis. Univariate analysis showed no significant associations between the baseline body composition indexes including SMI, VATI, SATI, and VSR and survival. Meanwhile, male sex (HR, 2.79; 95% CI, 1.16–6.71, p = 0.022) and higher decrease in VATI over 1 month (HR, 2.41; 95% CI, 1.13–5.13, p = 0.023) were identified as independent risk factors for mortality in multivariate analysis.ConclusionRapid decline in VAT over 1 month is closely associated with poorer survival in unresectable advanced pancreatic cancer. A short‐term assessment of body composition changes may be a rational approach to predict prognosis in these patients.

Comparison of bioimpedance spectroscopy and dual energy X-ray absorptiometry for assessing body composition changes in obese children during weight loss.

Obesity and age influence the reliability of dual energy X-ray absorptiometry scanning (DEXA) and bioimpedance spectroscopy (BIS). Both are used in clinical settings, but have not been compared for measurements in obese children. We compared DEXA and BIS for evaluating body composition and inherent changes in obese children before and after a 10-month weight loss programme. DEXA and BIS were used to evaluate 130 patients at baseline and 75 at follow-up. We tested agreement between the two techniques using Bland-Altman plots and proportional bias using Passing-Bablok regressions. The Bland-Altman plots showed wide agreement limits before and after weight loss and when monitoring longitudinal changes. At baseline, the Passing-Bablok regressions revealed a proportional bias for all body compartments. After significant weight loss no proportional bias was found for fat mass and percentage, although BIS systematically underestimated fat mass by 2.9 kg. Longitudinally, no proportional bias was found in the measured changes of absolute fat, fat-free mass and fat-free percentage between both methods, although BIS systematically underestimated fat and fat-free mass by 2.6 and 0.7 kg, respectively. While BIS and DEXA are not interchangeable at baseline, the agreement between the two improved after significant weight loss. Proportional changes in fat mass, fat-free mass and fat-free percentage were similar for both techniques. BIS is a viable alternative to DEXA for future paediatric obesity studies measuring treatment effect at group levels, but is not superior to DEXA and cannot be used for monitoring individual changes due to wide limits of agreement.

Impact on postoperative complications of changes in skeletal muscle mass during neoadjuvant chemotherapy for gastro-oesophageal cancer.

BackgroundRisk assessment is relevant to predict postoperative outcomes in patients with gastro‐oesophageal cancer. This cohort study aimed to assess body composition changes during neoadjuvant chemotherapy and investigate their association with postoperative complications.MethodsConsecutive patients with gastro‐oesophageal cancer undergoing neoadjuvant chemotherapy and surgery with curative intent between 2016 and 2019 were identified from a specific database and included in the study. CT images before and after neoadjuvant chemotherapy were used to assess the skeletal muscle index, sarcopenia, and subcutaneous and visceral fat index.ResultsIn a cohort of 199 patients, the mean skeletal muscle index decreased during neoadjuvant therapy (from 51·187 to 49·19 cm2/m2; P < 0·001) and the rate of sarcopenia increased (from 42·2 to 54·3 per cent; P < 0·001). A skeletal muscle index decrease greater than 5 per cent was not associated with an increased risk of total postoperative complications (odds ratio 0·91, 95 per cent c.i. 0·52 to 1·59; P = 0·736) or severe complications (odds ratio 0·66, 0·29 to 1·53; P = 0·329).ConclusionSkeletal muscle index decreased during neoadjuvant therapy but was not associated with postoperative complications.

Body Composition Changes after One Year in Professional Male Ice Hockey Players.

Body composition measurements remain one of the best objective ways to analyze tissue distribution in athletes. The purpose of this study was to establish an average body composition profile for professional male ice hockey players, assess the yearly fluctuations of body composition after a single season, and assess body composition changes among different positions. Body composition was measured using dual-energy X-ray absorptiometry in 36 professional male ice hockey players. Descriptive statistics were used to determine average values. A paired samples t-test was applied to determine differences over a one-year period. A one-way analysis of variance was used to determine differences between positions, at both time points. Alpha levels were set a priori at p<0.05. Significant increases were observed in percent body fat across time points for all positions (p=0.019). There were significant differences in percent body fat between positions played (p=0.012) after one year. We demonstrated that there was low variability among the different positions in professional male ice hockey players. Additionally, we observed how a single year minimally influences changes in body composition. More research is required to evaluate body composition in male ice hockey players.

Assessment of body composition changes during a combined intervention for the treatment of childhood obesity.

One of the main objectives in the treatment of childhood obesity is to reduce the percentage of body fat mass without negatively affecting fat-free mass (FFM) and, consequently, longitudinal growth. The aim of this study was to analyze the changes that take place in body compartments in a group of patients with obesity under combined treatment. This was a longitudinal study with 109 children with obesity 9.1 to 13.9 y of age included in a combined dietary-behavioral-physical activity intervention. Weight, height, skinfold thickness, and waist circumference were registered, and body mass index (BMI), fat mass index (FMI), FFM and waist-to-height ratio (WHR) were calculated over a period of 12 mo. The BMI z-score allowed us to establish two groups: obesity (n = 50) and severe obesity (n = 59). A nutritional improvement was considered when a decrease of BMI z-score of the initial value occurred after 12 mo of follow-up. The improvement in nutritional status reached 61.5% (n = 67). In the obesity group with nutritional improvement (n = 32), FMI significantly decreased (P < 0.005) and there were no significant differences in weight, height z-score, FFM, and WHR throughout the combined intervention. In the severe obesity group with nutritional improvement (n = 35), there were no significant differences in weight, height z-score, FMI, FFM, and WHR throughout combined intervention. Maintaining a constant weight in the mid- to long term to improve nutritional status would be adequate in children with infantile-juvenile obesity. However, maintaining a steady weight would not be sufficient for those patients diagnosed with severe obesity.

Gender-Specific Weight and Body Composition Changes Following Roux-en-Y Gastric Bypass

Purpose: Changes in weight and body composition, and rates of parameter change within and between genders, were studied preoperatively and serially within the first postoperative year after Roux-en-Y Gastric Bypass (RYGB). Analysis included 146 patients (115 women and 31 men) who were compliant with all visits. Preoperative variables included weight (Wt), body mass index (BMI), and body composition evaluated using ElectroLipoGraphy. Postoperatively, changes in those variables, percent excess weight loss (%EWL), and %Lean Lost (lean mass lost/weight loss) were evaluated. Main Findings: Both genders demonstrated significantly favorable Wt, BMI, %EWL, and body composition changes. %Lean Lost was the only parameter that did not significantly change for both genders. Between-gender changes were significant for all variables except BMI, %EWL, fat mass, and lean mass lost. No slopes of changes differed significantly between genders. Principal Conclusions: RYGB effectively accomplishes favorable weight and body compositions for both genders during the first postoperative year. Findings were used to suggest gender-specific, evidence-based clinical practice guidelines to assess body composition changes. Monitoring changes can help both genders achieve a healthier body weight primarily from fat mass loss while sparing lean mass.

Body Composition and Muscle Characteristics of Division I Track and Field Athletes.

The purpose of this study was to evaluate event-specific body composition and muscle characteristics of track and field athletes and to assess body composition changes after 1 year. Sixty collegiate track and field athletes (mean ± SD; age = 19.2 ± 1.4 years, height = 174.6 ± 9.0 cm, and weight = 71.5 ± 12.5 kg) were stratified into 6 event groups. Total and regional body composition measurements were assessed using dual-energy x-ray absorptiometry. A panoramic scan of the vastus lateralis was taken with B-mode ultrasound to determine muscle cross-sectional area and echo intensity (EI). Body composition measurements were repeated a year later in a subset of returning athletes (n = 33). Throwers had significantly more absolute fat mass (FM; 21.6 ± 11.0 kg), total body mass (89.7 ± 17.4 kg), percent fat (23.6 ± 7.8), and trunk fat (9.4 ± 5.8 kg) than all other event groups (p ≤ 0.05). Throwers had the most absolute lean mass (LM; 64.2 ± 11.7 kg; p > 0.05), but relative to body mass had relatively less LM (0.72 ± 0.08 kg; p ≤ 0.05). Despite high FM, throwers had lower EI (63.4 ± 5.2 a.u). After 1 year, relative armLM increased slightly in all event groups (p ≤ 0.05). Evaluation of muscle characteristics in addition to total and regional body composition may be valuable for improving performance, injury prevention, and assessing health risks. With appropriate training, track and field athletes may be able to minimize losses in LM and gains in FM between seasons.

Validity and Reliability of A-Mode Ultrasound for Body Composition Assessment of NCAA Division I Athletes.

This study evaluated the validity and reliability of the BodyMetrix™ BX2000 A-mode ultrasound for estimating percent body fat (%BF) in athletes by comparing it to skinfolds and the BOD POD. Forty-five (22 males, 23 females) National Collegiate Athletic Association (NCAA) Division-I athletes volunteered for this study. Subjects were measured once in the BOD POD then twice by two technicians for skinfolds and ultrasound. A one-way repeated-measures ANOVA revealed significant differences between body composition methods (F = 13.24, p < 0.01, η² = 0.24). This difference was further explained by a sex-specific effect such that the mean difference between ultrasound and BOD POD was large for females (~ 5% BF) but small for males (~ 1.5% BF). Linear regression using the %BF estimate from ultrasound to predict %BF from BOD POD resulted in an R2 = 0.849, SEE = 2.6% BF and a TE = 4.4% BF. The inter-rater intraclass correlation (ICC) for skinfold was 0.966 with a large 95% confidence interval (CI) of 0.328 to 0.991. The inter-rater ICC for ultrasound was 0.987 with a much smaller 95% CI of 0.976 to 0.993. Both skinfolds and ultrasound had test-retest ICCs ≥ 0.996. The BX2000 ultrasound device had excellent test-retest reliability, and its inter-rater reliability was superior to the skinfold method. The validity of this method is questionable, particularly for female athletes. However, due to its excellent reliability, coaches and trainers should consider this portable and easy to use A-mode ultrasound to assess body composition changes in athletes.

Comparison of amplitude-mode ultrasound versus air displacement plethysmography for assessing body composition changes following participation in a structuredweight-loss programme in women.

The purpose of this study was to compare body composition changes as measured by A-mode ultrasound (US) versus a criterion densitometry-based measure, air displacement plethysmography (ADP), over a 4-week weight-loss protocol in healthy, non-obese young women. Twenty healthy, young female volunteers were provided with customized dietary plans for the length of the study intended to facilitate a 500 calorie-a-day deficit. Subjects also performed 3h a week of supervised aerobic exercise. Per cent fat mass and lean body mass were obtained via ADP and US both pre- and postintervention. Pretesting, post-testing and delta data for %fat resulted in no significant differences in mean values along with a slope of the regression line no different than one and a y-intercept no different than zero (P<0·05). Similar to %fat values, pretesting, post-testing and delta data for fat-free mass resulted in no significant differences in mean values along with a slope of the regression line no different than one and a y-intercept no different than zero (P<0·05) with the exception of the delta for slope (0·39, P=0·04). The current findings indicate that US can provide a similar degree of accuracy for tracking group-based fat loss in women compared to ADP. Given the low-cost relative to DXA and ADP, researchers and practitioners therefore can consider US as a viable option for monitoring group-based changes in body fat over time.

Treatment of body composition changes in obese and overweight older adults: insight into the phenotype of sarcopenic obesity.

In recent years, mounting interest has been directed to sarcopenic obesity (SO), given the parallel increase of life expectancy and prevalence of obesity in Western countries. The phenotype of SO is characterized by the coexistence of excess fat mass and decreased muscle mass, leading to the impairment of physical performance. The aim of the present review was to summarize the impact of different treatment strategies contrasting body composition changes in older obese and overweight subjects, providing insight into the SO phenotype. Revision questions were formulated; relevant articles were identified from Pubmed through a systematic search strategy: definition of the search terms (sarcopenic obesity, diet, nutritional supplements, physical activity, exercise, pharmacological treatment); limits: papers published in the last 10 years; humans; age ≥ 60 years old; body mass index >25 kg/m(2); language: English. Studies dealing with sarcopenia associated to cancer cachexia or neurological diseases, any malignant disease, inflammatory or autoimmune diseases, corticosteroids for systemic use, bedridden subjects, and syndromic obesity were excluded. 14 articles were identified for inclusion in the present systematic review, and were grouped basing on the type of the main intervention: data assessing body composition changes after combined lifestyle interventions, exercise/physical activity, dietary interventions, and pharmacological treatment. Most of the studies were randomized, controlled. Sample size ranged from 12 to 439 subjects, and study duration varied from 6 weeks to 12 months. Weight loss based on diet combined with exercise seems to be the best strategy to adopt for treatment of phenotypic aspects of SO, improving metabolic consequences related to excess fat, preserving lean mass, and allowing functional recovery.

Body composition changes in pregnancy: measurement, predictors and outcomes.

Prevalence of overweight and obesity has risen in the United States over the past few decades. Concurrent with this rise in obesity has been an increase in pregravid body mass index and gestational weight gain affecting maternal body composition changes in pregnancy. During pregnancy, many of the assumptions inherent in body composition estimation are violated, particularly the hydration of fat-free mass, and available methods are unable to disentangle maternal composition from fetus and supporting tissues; therefore, estimates of maternal body composition during pregnancy are prone to error. Here we review commonly used and available methods for assessing body composition changes in pregnancy, including: (1) anthropometry, (2) total body water, (3) densitometry, (4) imaging, (5) dual-energy X-ray absorptiometry, (6) bioelectrical impedance and (7) ultrasound. Several of these methods can measure regional changes in adipose tissue; however, most of these methods provide only whole-body estimates of fat and fat-free mass. Consideration is given to factors that may influence changes in maternal body composition, as well as long-term maternal and offspring outcomes. Finally, we provide recommendations for future research in this area.

Measurement of body composition changes during weight loss in obese men using multi-frequency bioelectrical impedance analysis and multi-compartment models

The accurate measurement of changes in body composition is important to assess the contribution of fat and fat free mass to total body mass change as a measure of the effectiveness of weight loss programmes. Bioelectrical impedance spectroscopy (BIS) is a rapid and non-invasive technique which could be applied to assess body composition changes. The aim of the study was to evaluate the accuracy of the BIS for the measurement of fat mass (FM), total body water (TBW) and extracellular water (ECW) changes induced by different degrees of caloric deficit in obese men. Three groups of six, obese men participated in either (i) a total fast (for 6 days); (ii) a VLCD (2.5 MJ/day for 3 weeks); or (iii) LCD (5.2 MJ/day for 6 weeks). FM was measured using a 4-compartment (4-C) model. TBW and ECW were determined by dilution methods, respectively. TBW, ECW and FM were also assessed with BIS. Body weight loss in the fasting group was 6.0 ± 1.3 kg over 6 days; the VLCD group lost 9.2 ± 1.2 kg over 21 days and the LCD group lost 12.6 ± 2.4 kg over 42 days. BIS underestimated FM changes (bias = -3.3 ± 3.8 kg) and overestimated changes in TBW and ECW by +1.8 ± 4.8 kg and +2.3 ± 6.4 kg, respectively. The measurement error was consistently larger in the fasting group and the magnitude of the bias interacted significantly with the rate of weight loss. Rapid weight loss affects the accuracy of the BIS in detecting changes in body composition. A careful interpretation of the results is needed when sizable changes in body water compartments occurs.

Quality of Growth in Exclusively Breast-Fed Infants in the First Six Months of Life: An Italian Study

Nutrition in early life, growth, and subsequent health over a lifetime are significantly interrelated. The aim of this study was to assess body composition changes in exclusively breast-fed infants from birth up to 6 mo of age. An observational, prospective, cohort study was conducted. Fifty-nine full-term, healthy, exclusively breast-fed infants underwent assessment of growth and body composition, using air-displacement plethysmograph (i.e. PEA POD) by Life Measurement, Inc. (Concord, CA). Body composition was assessed at birth, 2 wk, and 1, 2, 3, 4, 5, and 6 mo of age. Mean birth weight (g) and gestational age (wk) of the infants were 3170 ± 420 and 39.21 ± 1.29, respectively. Percentage of fat mass increased significantly over the first 4 mo (p < 0.001), both in boys and girls, with no differences detected between boys and girls at any time point. This article provides preliminary in-depth data on whole-body composition, in exclusively breast-fed infants during the first months of life. Further studies assessing larger sample sizes are desirable to develop reference body composition data.

Validity Of Single-frequency Bioelectrical Impedance Method To Assess Changes In Body Composition During Exercise Training

PURPOSE: To investigate the validity of single-frequency bioelectrical impedance method (BI; Muscle-alpha, Physion) to assess body composition changes during a 12-week aerobic exercise program in comparison with dual-energy X-ray absorptiometry (DXA; QDR 4500, Hologic). METHODS: Eighteen obese men (age: 49.1 ± 11.3 years, body mass index: 28.7 ± 1.8 kg/m2) participated in this study. They enrolled in a 90-min supervised exercise program mainly consisting of aerobic exercise (60-80% of heart rate reserve) on a regular basis of 3 d/wk for 12 weeks. Percentage of fat mass (%fat), fat mass (FM) and fat-free mass (FFM) were measured before and after the program using BI and DXA. RESULTS: With -2.7 ± 2.4 kg of weight reduction during the program, %fat and FM significantly decreased (P < 0.05), but FFM remained unchanged when assessed by BI and DXA. Significant differences (P < 0.05) were observed between BI and DXA at baseline for %fat (28.2% vs. 25.4%), FM (23.5 kg vs. 21.3 kg) and FFM (59.7 kg vs. 62.6 kg). Further, significant differences (P < 0.05) were observed after the program for %fat (25.2% vs. 23.3%), FM (20.4 kg vs. 19.0 kg) and FFM (60.2 kg vs. 62.3 kg) and change in FM (-3.1 kg vs. -2.3 kg). At each time point, %fat, FM and FFM measured by BI were significantly lower (P < 0.05) than those by DXA. The correlation coefficients between BI and DXA were similar at baseline and after the program, while rather low for the change in %fat (r = 0.63, 0.69, and 0.33, respectively), FM (r = 0.81, 0.86, and 0.59, respectively) and FFM (r = 0.98, 0.98, and 0.15, respectively). A Bland-Altman analysis revealed no significant bias (change%fat: r = -0.21, standard error of estimate: SEE = 1.36, P = 0.40; changeFM: r = -0.09, SEE = 1.54, P = 0.72; changeFFM: r = -0.35, SEE = 0.96, P = 0.16). CONCLUSIONS: BI and DXA are able to track changes in %fat and FM similarly during an aerobic exercise program in obese men. Additionally, there are no significant differences in %fat and FM between the two methods, suggesting that BI can be used in a clinical setting.

Utility of circulating IGF-I as a biomarker for assessing body composition changes in men during periods of high physical activity superimposed upon energy and sleep restriction

Insulin-like growth factor (IGF)-I is a biomarker that may have greater utility than other conventional nutritional biomarkers in assessing nutritional, health, and fitness status. We hypothesized that the IGF-I system would directionally track a short-term energy deficit and would be more related to changes in body composition than other nutritional biomarkers. Thirty-five healthy men (24 +/- 0.3 yr) underwent 8 days of exercise and energy imbalance. Total and free IGF-I, IGF binding proteins-1, -2, and -3, the acid labile subunit, transferrin, ferritin, retinol binding protein, prealbumin, testosterone, triiodothyronine, thyroxine, and leptin responses were measured. Dual-energy X-ray absorptiometry assessed changes in body mass and composition. Repeated-measures ANOVA, correlation analysis, and receiver operator characteristic curves were used for statistical analyses (P < or = 0.05). Body mass (-3.8%), fat-free mass (-2.2%), and fat mass (-12.9%) all decreased. Total and free IGF-I, IGF binding protein-3, and the acid labile subunit and prealbumin, but not transferrin, retinol-binding protein, and ferritin, directionally tracked the energy deficit and losses in body composition. The correlation (r = 0.43) between changes in free IGF-I and body and fat-free mass was the only significant association observed. Receiver operator characteristic curve analysis revealed that a baseline value < 1.67 for the molar volume ratio of IGF-I to acid labile subunit had an area under the curve of 0.745 and was a significant discriminator for those subjects losing >5% body mass. The IGF-I system is an important adjunct in the overall assessment of adaptation to stress imposed by high levels of physical activity superimposed on energy and sleep restriction and is more closely associated with losses in body mass and fat-free mass than other conventional nutritional biomarkers.

Metabolic Effects of PIs vs. NNRTIs

Chronic conditions such as diabetes, cardiovascular disease, and the metabolic syndrome may be more common in HIV-infected people than in the general population. Data support the concern that antiretroviral therapy, and possibly specific drug choices, may contribute to the premature onset of these diseases or increase their severity. In a substudy of the FIRST (Flexible Initial Retrovirus Suppressive Therapies) trial, investigators assessed changes in metabolic parameters and body composition among 422 antiretroviral-naive patients randomized to start therapy with two NRTIs plus either a PI, an NNRTI, or a PI + NNRTI. The most commonly used PIs were nelfinavir (61%), …