How body composition techniques measure up for reliability across the age-span

Least significant change with repeat bioelectrical impedance analysis measurements in children with metabolic dysfunction-associated steatotic liver disease: A descriptive cohort study

BACKGROUND

Bioelectrical impedance is used clinically to assess body composition. To determine true (rather than chance/measurement error) change in bioelectrical impedance analysis measurements over time, it is necessary to know their least significant change. Least significant change represents values exceeding the 95% prediction interval of the precision error of repeat measurements. The least significant change of repeat bioelectrical impedance analysis measurements in children with obesity and metabolic dysfunction-associated steatotic liver disease is currently unknown.

METHODS

This is a prospective, single-center, descriptive cohort study in youth 6-20 years of age with obesity and metabolic dysfunction-associated steatotic liver disease. Two same-day bioelectrical impedance analysis measurements were performed on a multifrequency, octopolar device (InBody 370). Fat mass and fat-free mass were adjusted for age using respective indices (dividing by height squared). Fasting status was determined by patient report. Descriptive statistics (medians with interquartile ranges and means with standard deviations and proportions) were used; the least significant change between repeat measurements with precision interval was calculated.

RESULTS

We recruited 43 patients (81% male; 33% Hispanic; median age: 14 years [interquartile range: 11-16]; median body mass index z score: 2.31 [interquartile range: 2.84-2.65]). A total of 60% were fasting, for a median of 12 h. The least significant change of fat mass index was 0.5 (precision interval: -0.4 to 0.5) kg/m2, fat-free mass index was 0.3 (precision interval: -0.3 to 0.3) kg/m2, and body fat percent was 1.5% (precision interval: -1.3 to 1.50). Fasting status affected least significant change measurements.

CONCLUSION

In youth with obesity and metabolic dysfunction-associated steatotic liver disease, repeat bioelectrical impedance analysis measurements beyond least significant change and precision interval determined in this study likely represent true changes in body composition over time, vs measurement error.

Efficacy of Interval Training in Improving Body Composition and Adiposity in Apparently Healthy Adults: An Umbrella Review with Meta-Analysis

BACKGROUND

Although the efficacy of interval training for improving body composition has been summarized in an increasing number of systematic reviews in recent years, discrepancies in review findings and conclusions have been observed.

OBJECTIVE

This study aims to synthesize the available evidence on the efficacy of interval training compared with moderate-intensity continuous training (MICT) and nonexercise control (CON) in reducing body adiposity in apparently healthy adults.

METHODS

An umbrella review with meta-analysis was performed. A systematic search was conducted in seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) up to October 2023. Systematic reviews with meta-analyses of randomized controlled trials (RCTs) comparing interval training and MICT/CON were included. Literature selection, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers. Meta-analyses were performed using a random-effects model. Subgroup analyses were conducted based on the type of interval training [high-intensity interval training (HIIT) and sprint interval training (SIT)], intervention duration, body mass index, exercise modality, and volume of HIIT protocols.

RESULTS

Sixteen systematic reviews, including 79 RCTs and 2474 unique participants, met the inclusion criteria. Most systematic reviews had a critically low (n = 6) or low (n = 6) AMSTAR-2 score. Interval training demonstrated significantly greater reductions in total body fat percent (BF%) compared with MICT [weighted mean difference (WMD) of - 0.77%; 95% confidence interval (CI) - 1.12 to - 0.32%] and CON (WMD of - 1.50%; 95% CI - 2.40 to - 0.58%). Significant reductions in fat mass, visceral adipose tissue, subcutaneous abdominal fat, and android abdominal fat were also observed following interval training compared to CON. Subgroup analyses indicated that both HIIT and SIT resulted in superior BF% loss than MICT. These benefits appeared to be more prominent in individuals with overweight/obesity and longer duration interventions (≥ 12 weeks), as well as in protocols using cycling as a modality and low-volume HIIT (i.e., < 15 min of high-intensity exercise per session).

CONCLUSIONS

This novel umbrella review with large-scale meta-analysis provides an updated synthesis of evidence with implications for physical activity guideline recommendations. The findings support interval training as a viable exercise strategy for reducing adiposity in the general population.

Technical and Biological Reliability of pQCT Measured Bone and Muscle Tissue Quality Across the Age-Span

INTRODUCTION

Reliable peripheral quantitative computed tomography (pQCT) assessment is essential to the accurate longitudinal reporting of bone and muscle quality. However, the between-day reliability of pQCT and the influence of age on outcome reliability is currently unknown.

OBJECTIVE

To quantify the same- and between-day reliability of morphological pQCT at proximal and distal segments of the forearm, shank, and thigh, and explore the influence of participant body size, age, and sex on outcome reliability.

METHODS

Men and women (49 % female, 18-85 years, n=72-86) completed two consecutive-day pQCT testing sessions, where repeat measurements were conducted on day-one for technical error, and between-day for biological error quantification. Testing was undertaken following best practice body composition testing guidance, including standardized presentation and consistent time-of-day.

RESULTS

All measurements of bone were classified as having 'good' to 'excellent' reliability [intraclass correlation coefficient (r=0.786- 0.999], as were measurements of muscle area (ICC r=0.991-0.999) and total fat (r=0.996-0.999). However, between- and same-day muscle density measurements at the thigh and forearm were classified as 'poor' (r=0.476) and 'moderate' (r=0.622), respectively. Likewise, intramuscular fat area at the thigh was classified as 'moderate' (r=0.737) for between-day measurement. Biological error was inflated compared to technical error by an average of 0.4 % for most measurements. Error values tended to increase proportionally with the amount of tissue quantified and males had significantly greater biological error for measurement of distal tibial bone (p<0.002) and trabecular area (p<0.002). Biological error was inflated among older adults for measurement of forearm muscle density (p<0.002).

CONCLUSIONS

Most pQCT outcomes can be implemented with confidence, especially outcomes that assess bone area and density at any of the radial, tibial, and femoral sites investigated herein. However, it is important to account for the influence of biological measurement error in further studies, especially for muscle and intramuscular fat outcomes derived by pQCT.

Interleukin-15 and high-intensity exercise: relationship with inflammation, body composition and fitness in cancer survivors

Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth. These anti-oncogenic effects of exercise were associated with the exercise-mediated release of myokines such as interleukin (IL)-15. However, no study has quantified the acute IL-15 response in human cancer survivors, and whether physiological adaptations to exercise training (i.e. body composition and cardiorespiratory fitness) influence this response. In the present study breast, prostate and colorectal cancer survivors (n = 14) completed a single bout of high-intensity interval exercise (HIIE) [4×4 min at 85-95% heart rate (HR) peak, 3 min at 50-70% HR peak] before and after 7 months of three times weekly high-intensity interval training (HIIT) on a cycle ergometer. At each time point venous blood was sampled before and immediately after HIIE to assess the acute myokine (IL-15, IL-6, IL-10, IL-1ra) responses. Markers of inflammation, cardiorespiratory fitness and measures of body composition were obtained at baseline and 7 months. An acute bout of HIIE resulted in a significant increase in IL-15 concentrations (pre-intervention: 113%; P = 0.013, post-intervention: 102%; P = 0.005). Post-exercise IL-15 concentrations were associated with all other post-exercise myokine concentrations, lean mass (P = 0.031), visceral adipose tissue (P = 0.039) and absoluteV ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ peak (P = 0.032). There was no significant effect of 7 months of HIIT on pre- or post-HIIE IL-15 concentrations (P > 0.05). This study demonstrates HIIE is a sufficient stimulus to increase circulating IL-15 and other myokines including IL-6, IL-10 and IL-1ra which may be clinically relevant in the anti-oncogenic effect of exercise and repetitive exposure to these effects may contribute to the positive relationship between exercise and cancer recurrence. KEY POINTS: Exercise has been demonstrated to reduce the risk of cancer recurrence. Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth, mediated by exercise-induced myokines (IL-6 and IL-15). High-intensity interval exercise significantly increased myokines associated with the anti-oncogenic effect of exercise and the magnitude of response was associated with lean mass, but training did not appear to influence this response. Given IL-15 has been implicated in the anti-oncogenic effect of exercise and is being explored as an immunotherapy agent, high-intensity interval exercise may improve outcomes for people living beyond cancer through IL-15-mediated pathways. Interventions that increase lean mass may also enhance this response.

Efficacy of exercise interventions for women during and after gynaecological cancer treatment - a systematic scoping review

PURPOSE

To systematically synthesise evidence of exercise intervention efficacy for physical/psychosocial outcomes that matter to women during/following treatment for gynaecological cancer.

METHODS

Five databases were searched (PubMed, EMBASE, CINAHL, PsychInfo, Scopus). Exercise-only intervention studies that included women during/ following treatment for any gynaecological cancer, with/ without control comparison, on any physical or psychosocial outcome(s), were included and qualitatively appraised using the Revised Cochrane Risk of Bias tool and a modified Newcastle-Ottawa Scale.

RESULTS

Seven randomised controlled trials (RCTs), three single-arm pre-post studies, and one prospective cohort study satisfied were included (11 studies). Most studies were completed following treatment (91%), included combined (aerobic and resistance; 36%) and aerobic (36%) training, were fully/mostly (63%) unsupervised, and had a moderate-to-high risk of bias. Overall, 33 outcomes (64% objectively-measured) were assessed. Improvements were observed in aerobic capacity (V̇O2 Peak +1.6 mL/kg/min, 6-minute walk distance +20-27 m), lower- (30-second sit-to-stand +2-4 repetitions) and upper-limb strength (30-second arm curl +5 repetitions; 1RM grip strength/chest press +2.4-3.1 kg), and agility (timed up-and-go -0.6 seconds). However, changes in quality of life, anthropometry/body composition, balance and flexibility were inconsistent. There was no evidence to support worsening of outcomes.

CONCLUSION

Preliminary research into the role of exercise post-gynaecological cancer suggests an improvement in exercise capacity, muscular strength, and agility which, in the absence of exercise, typically decline following gynaecological cancer. Future exercise trials involving larger and more diverse gynaecological cancer samples will improve understanding of the potential and magnitude of effect of guideline-recommended exercise on outcomes that matter to patients.

Impact of 24-Hr Diet and Physical Activity Control on Short-Term Precision Error of Dual-Energy X-Ray Absorptiometry Physique Assessment

Dual-energy X-ray absorptiometry (DXA) is a popular technique used to quantify physique in athletic populations. Due to biological variation, DXA precision error (PE) may be higher than desired. Adherence to standardized presentation for testing has shown improvement in consecutive-day PE. However, the impact of short-term diet and physical activity standardization prior to testing has not been explored. This warrants investigation, given the process may reduce variance in total body water and muscle solute, both of which can have high daily flux amongst athletes. Twenty (n = 10 males, n = 10 females) recreationally active individuals (age: 30.7 ± 7.5 years; stature: 176.4 ± 9.1 cm; mass: 74.6 ± 14.3 kg) underwent three DXA scans; two consecutive scans on 1 day, and a third either the day before or after. In addition to adhering to standardized presentation for testing, subjects recorded all food/fluid intake plus activity undertaken in the 24 hr prior to the first DXA scan and replicated this the following 24 hr. International Society of Clinical Densitometry recommended techniques were used to calculate same- and consecutive-day PE. There was no significant difference in PE of whole-body fat mass (479 g vs. 626 g) and lean mass (634 g vs. 734 g) between same- and consecutive-day assessments. Same- and consecutive-day PE of whole-body fat mass and lean mass were less than the smallest effect size of interest. Inclusion of 24-hr standardization of diet and physical activity has the potential to reduce biological error further, but this needs to be verified with follow-up investigation.

Between-day reliability of cytokines and adipokines for application in research and practice

Purpose: This study assessed the biological reliability of peripheral human cytokines and adipokines, and the influence of participant characteristics on total error. This has essential application to interventional cytokine measurement to ensure that reported results are interpreted with confidence.

Methods: Participants (49% female, 18–85 years, n = 84) completed two consecutive-day testing sessions. Participants provided a venous blood sample at the same time of day across two consecutive days, under standardized participant presentation, including 24-h rested and 12-h fasted conditions. Multiplex immunoassay was used to assess inflammatory analytes from samples (predominantly plasma). Repeat measurements were conducted between-day for total precision quantification, and technical (technique) error was negated from the total to provide an estimate of biological (attributed to participant presentation) error.

Results: Whilst there was no evidence of statistically significant biological error, a small amount of biological error was consistently present across most analytes (∼3.3%/0.07 pg/ml), which was largest for measurement of leptin (7.3%/210 pg/ml). There was also an influence of sex on reliability of leptin and adiponectin (total model explained 6–7% of error variation), where females demonstrated the greatest error.

Conclusion: Biological error reported in this study should be applied to any future study or individual with a repeated measurement of cytokine concentrations over time that maintain best practice procedures (12-h fasted, 24-h rested). In most cases, raw error should be used, with exceptions for women for measurement of leptin and adiponectin. This approach will ensure that results are reported with certainty for improved reporting of intervention efficacy.

Accuracy of body composition measurement techniques across the age span

This study investigated the acceptable accuracy of common body composition techniques compared with the reference 4-compartment (4C-R) model, which has not been investigated in a sample with diverse characteristics, including age and sex. Techniques included components of the 4C-R model [dual-energy X-ray absorptiometry, air displacement plethysmography, deuterium dilution (DD)] and surrogate compartment models, which utilised bioelectrical impedance spectroscopy (BIS) rather than DD. Men and women (sex = 1:1, 18-85 years, n = 90) completed body composition testing under best-practice guidance. For measurement of individuals, only the reference 3-compartment (3C-R) equation met acceptable error limits (<5% error among individuals) within the a priori cut-point (80%) for fat-free mass (FFM; CV = 0.52%) and fat mass (FM; CV = 1.61%). However, all investigated techniques reached equivalency to the 4C-R model for FFM on average (CV = 0.52-4.31%), but for FM only the 3C and 4C equations that included quantification of total body water (TBW) by DD or BIS reached equivalency overall (CV = 1.61-6.68%). Sex and age minimally influenced accuracy. Only the 3C-R or 4C-R equations are supported for acceptable individual accuracy for both FFM and FM. For group estimates any investigated technique could be used with acceptable accuracy for FFM; however, for FM, inclusion of TBW measurement within a compartment model is necessary. Novelty: Only the referent 3C and 4C models (including deuterium dilution) provide accurate body composition results that are acceptable for measurement of individuals in the general population. For group estimates of lean mass in the general population, compartments models that include TBW must be used for accurate measurement.

The acute effect of the menstrual cycle and oral contraceptive cycle on measures of body composition

PURPOSE

This study aimed to investigate the effect of fluctuating female hormones during the menstrual cycle (MC) and oral contraceptive (OC) cycle on different measures of body composition.

METHODS

Twenty-two women with a natural MC and thirty women currently taking combined monophasic OC were assessed over three phases of the menstrual or oral contraceptive cycle. Body weight, skinfolds, bioelectric impedance analysis (BIA), ultrasound, dual-energy X-ray absorptiometry (DXA), and peripheral quantitative computed tomography (pQCT) measurements were performed to assess body composition. Urine specific gravity (USG) was measured as an indication of hydration, and serum oestradiol and progesterone were measured to confirm cycle phases.

RESULTS

Five participants with a natural MC were excluded based on the hormone analysis. For the remaining participants, no significant changes over the MC and OC cycle were found for body weight, USG, skinfolds, BIA, ultrasound and pQCT measures. However, DXA body fat percentage and fat mass were lower in the late follicular phase compared to the mid-luteal phase of the MC, while for the OC cycle, DXA body fat percentage was higher and lean mass lower in the early hormone phase compared with the late hormone phase.

CONCLUSION

Our findings suggest that assessment of body fat percentage through BIA and skinfolds may be performed without considering the MC or OC cycle. Body adiposity assessment via DXA, however, may be affected by female hormone fluctuations and therefore, it may be advisable to perform repeat testing using DXA during the same phase of the MC or OC cycle.