Definition of an adapted cut-off for determining low lean tissue mass in older women with obesity: a comparison to current cut-offs

Cross-Calibration of Areal Bone Mineral Densities and Body Composition between DMS Stratos and Hologic Horizon A Dual-Energy X-ray Absorptiometers: The Effect of Body Mass Index

PURPOSE

The aim of this study was to investigate the correlations between areal bone mineral density (aBMD) and body composition measured by two dual-energy X-ray absorptiometers (DXA), the DMS Stratos® (STR) and the Hologic Horizon A® (HRZ), and then generate cross-calibration equations between the two scanners.

METHODS

Repeat scans were obtained from 251 adults (85 % female), 36 ± 14 years old with mean body mass index (BMI) of 28.7 ± 11.1 kg/m2, using HRZ (fan-beam technology) and STR (pencil-beam technology). aBMD was measured at whole body [WB], femoral neck [FN], total hip [TH], lumbar spine [LS] and radius, while fat mass [FM] and lean tissue mass [LTM] were determined at whole body and at android and gynoid subregions.

RESULTS

Compared to HRZ, STR underestimated both aBMD at WB and radius and LTM at WB and android and gynoid regions. Conversely, STR overestimated aBMD at FN, TH, LS and FM at WB android and gynoid regions. Except for WB bone mineral content (r = 0.87) and WB aBMD (r = 0.84), there were strong correlations of aBMD and body composition between the two DXAs (r > 0.91; p < 0.0001). Several of the parameters that required the determination of specific cross-calibration equations because of the significant bias between the two DXAs were found to be influenced by BMI.

CONCLUSIONS

Although the data from the STR and the HRZ were highly correlated for aBMD and body composition parameters, a systematic measurement bias between two DXAs was observed. The development of cross-calibration equations fully corrected these differences and they may thus be useful for multicenter studies when scans are performed with STR and HRZ.

Definition, diagnosis, and treatment of respiratory sarcopenia

PURPOSE OF REVIEW

Skeletal muscle weakness and wasting also occurs in the respiratory muscles, called respiratory sarcopenia. Respiratory sarcopenia may lead to worse clinical indicators and outcomes. We present a novel definition and diagnostic criteria for respiratory sarcopenia, summarize recent reports on the association between respiratory sarcopenia, physical and nutritional status, and clinical outcomes, and provide suggestions for the prevention and treatment of respiratory sarcopenia.

RECENT FINDINGS

Recently, a novel definition and diagnostic criteria for respiratory sarcopenia have been prepared. Respiratory sarcopenia is defined as a condition in which there is both low respiratory muscle strength and low respiratory muscle mass. Respiratory muscle strength, respiratory muscle mass, and appendicular skeletal muscle mass are used to diagnose respiratory sarcopenia. Currently, it is challenging to definitively diagnose respiratory sarcopenia due to the difficulty in accurately determining low respiratory muscle mass. Decreased respiratory muscle strength and respiratory muscle mass are associated with lower physical and nutritional status and poorer clinical outcomes. Exercise interventions, especially respiratory muscle training, nutritional interventions, and their combinations may effectively treat respiratory sarcopenia. Preventive interventions for respiratory sarcopenia are unclear.

SUMMARY

The novel definition and diagnostic criteria will contribute to promoting the assessment and intervention of respiratory sarcopenia.

Relationship between Lean Tissue Mass and Muscle Function in Women with Obesity

It is well documented that lean tissue mass (LTM) decreases with aging in patients with obesity, but there is no information available regarding muscle strength changes, a parameter that may be better associated with sarcopenic obesity (SO). The objectives of this study were to analyze the changes in LTM and fat mass (FM), muscle strength and muscle function with aging in women with obesity and to determine the prevalence of SO. LTM and FM were determined by DXA, muscle strength with the hand-grip test and muscle function with the 6 min walk test (6MWT) in 383 women with obesity. A redistribution of the LTM and FM occurred with age, characterized by a gain at the trunk to the detriment of the lower limbs, thus reducting in appendicular LTM indices. The physical performances evaluated by the muscle strength and muscle function decreased concomitantly, and the prevalence of low values for both these parameters was 22.8% and 13.4%, respectively, in the older patients. In summary, although a reduction in appendicular LTM and muscle performances occurred with age and resulted in an increase in the prevalence of SO, the number of women with obesity affected by SO remained low (n ≤ 15), even in those older than 60 years.

Cross-Calibration Study of The Stratos And Hologic QDR 4500A Dual-Energy X-Ray Absorptiometers to Assess Bone Mineral Density And Body Composition

The objective of the study was to assess the agreement between the Stratos (DMS) and QDR 4500A (Hologic) DXAs in determining whole body and regional aBMD, as well as whole body composition. Fifty-five individuals (46 women: 84%) with a mean age of 41 ± 13.0 years (range: 20 to 64) and a mean BMI of 31.9 ± 10 kg/m² (range: 12.2 to 49.5) were consecutively scanned on the same day using the two devices. Predictive equations for areal bone mineral density (aBMD) and whole body composition (WBC) were derived from linear regression of the data. The two DXAs were highly correlated (p<0.001 for all parameters) with a correlation coefficient (r) ranging from 0.89 to 0.99 for aBMD (r=0.89 for whole body, r=0.92 for radius, r=0.95 for femoral neck, r=0.96 for total hip, and r=0.99 for L1-L4). For WBC, the r value was 0.98 for lean tissue mass (LTM) and 1.0 for fat mass (FM). Paired t-tests indicated a statistically significant bias between the two DXAs for the majority of measurements, requiring the determination of specific cross-calibration equations. Compared to QDR 4500A, Stratos underestimated whole body aBMD and LTM and overestimated neck and hip aBMD and whole body FM. Conversely, no significant bias was demonstrated for mean aBMD at L1-L4 and radius. For whole body aBMD and FM, the concordance between the two DXAs was influenced by BMI. Despite a high concordance between the two DXAs, the systematic bias for aBMD and WBC measurements illustrates the need to define cross-calibration equations to compare data across systems.

Changes in Lean Tissue Mass, Fat Mass, Biological Parameters and Resting Energy Expenditure over 24 Months Following Sleeve Gastrectomy

Sleeve gastrectomy (SG) induces weight loss but its effects on body composition (BC) are less well known. The aims of this longitudinal study were to analyse the BC changes from the acute phase up to weight stabilization following SG. Variations in the biological parameters related to glucose, lipids, inflammation, and resting energy expenditure (REE) were concomitantly analysed. Fat mass (FM), lean tissue mass (LTM), and visceral adipose tissue (VAT) were determined by dual-energy X-ray absorptiometry in 83 obese patients (75.9% women) before SG and 1, 12 and 24 months later. After 1 month, LTM and FM losses were comparable, whereas at 12 months the loss of FM exceeded that of LTM. Over this period, VAT also decreased significantly, biological parameters became normalized, and REE was reduced. For most of the BC, biological and metabolic parameters, no substantial variation was demonstrated beyond 12 months. In summary, SG induced a modification in BC changes during the first 12 months following SG. Although the significant LTM loss was not associated with an increase in sarcopenia prevalence, the preservation of LTM might have limited the reduction in REE, which is a longer-term weight-regain criterion.

Consequences of applying the different criteria of the EWGSOP2 guideline for sarcopenia case-finding in Spanish community-dwelling older adults

INTRODUCTION

Sarcopenia prevalence varies according to differences in diagnostic criteria used. In order to overcome this issue, the European Working Group on Sarcopenia in Older People-2 (EWGSOP2) published a consensus to increase harmonization for sarcopenia diagnosis. This study aimed to determine the prevalence and risk factors across the different sarcopenia diagnosis criteria recommended by EWGSOP2 and to analyze its agreement.

METHODS

A total of 699 community-dwelling older adults (median-age: 72, 60% female) were recruited in this cross-sectional study. Sarcopenia prevalence was obtained by different combinations of muscle strength (handgrip strength or 5-times sit-to-stand) and muscle quantity (appendicular skeletal mass or skeletal muscle index) as recommended by the EWGSOP2. Cohen's Kappa coefficient was calculated to analyze agreement among the four sarcopenia diagnostic criteria and logistic regressions were performed to identify risks associated to health-related outcomes for each diagnostic criterion.

RESULTS

Sarcopenia prevalence varied from 2.1% to 11.6%, depending on the diagnostic criteria used. Weak-to-moderate agreements (κ-range: 0.13-0.66) were observed among the four sarcopenia diagnosis criteria. There was scarce overlap in sarcopenic people when different diagnostic criteria were used leading to up to 10.4% of underdiagnosis. Sarcopenia defined by 5-times sit-to-stand was more associated with health-related outcomes compared to handgrip strength.

CONCLUSIONS

Sarcopenia prevalence rates vary considerably depending on the diagnostic criteria used. These criteria should not be used in an interchangeable way due to their weak agreement. Sarcopenia diagnosis criteria defined by 5-times sit-to-stand could be more suitable in Spanish community-dwelling older adults due their associations with health-related outcomes.