Dual X-ray absorptiometry assessment of body composition in children with altered body posture

Effects of biologic and target synthetic disease-modifying anti-rheumatic drugs on sarcopenia in spondyloarthritis and rheumatoid arthritis: a systematic review and meta-analysis

Sarcopenia is a syndrome defined by generalized and progressive loss of skeletal muscle mass, strength, and function. Besides affecting elderly population, it is actually common among inflammatory rheumatic diseases (IRD) patients. We performed a systematic literature review with a meta-analysis to investigate the influence of biologic and target synthetic disease-modifying anti-rheumatic drugs (bDMARDs/tsDMARDs) on sarcopenia in IRD. A systematic search has been performed on Pubmed, Scopus, and Web of science. Studies characteristics were collected. Assessment tools were body composition (total lean mass (TLM) and percentage, appendicular skeletal mass (ASM), fat-free mass and index (FFM and FFMI), skeletal mass index (SMI) and segmental lean mass (SLM)), and muscle strength and physical performance tests. Treatment effect defined the difference in change from baseline to the end of follow-up treatment was divided by the pooled SD of the difference. Twenty-two studies on 778 patients receiving bDMARDs/tsDMARDs and 157 controls were reviewed. They investigated rheumatoid arthritis (RA) (N = 14), spondyloarthritis (SpA) (N = 6), psoriatic arthritis (N = 1), and both RA and SpA (N = 1). tsDMARDs were used in one study with no effect on sarcopenia. Ten studies demonstrated that bDMARDs increased significantly muscle measures in 347 patients (44.6%) with a significant increase in TLM (6/15 studies; 57.4%), FFMI (4/6 studies; 59.9%), ASM (2/5 studies; 17.6%), SMI (2/5 studies; 18.1%), and SLM (2/2 studies; 3.6%). bDMARDs showed also a positive effect on handgrip strength in 1/3 of studies (45.2%) and on physical performance in 1/2 of studies (61%). In 1/5 of comparative studies, IRD patients on bDMARDs showed significantly higher increase of TLM in comparison to controls naïve bDMARDs. Regarding diagnosis, positive effect of bDMARDs was seen in 67.4% in SpA versus 49.3% in RA, with a significant increase of TLM, ASM and FFMI in 59.4%, 100%, and 65.2% in SpA versus 54.9%, 24.1%, and 54.8% in RA, respectively. Meta-analysis assessed the effect of bDMARD on TLM in 10 studies. There was no statistically significant difference [SMD - 0.10 (95% Confidence Interval - 0.26 - 0.06; tau² = 0). Heterogeneity across studies was null, and the 95% confidence interval (index of precision) was equal to the 95% predictive interval. The first systematic literature review showed that bDMARDs have a significant improve effect in nearly half of RA and SpA patients on muscle mass and muscle strength, assessed separately. However, the meta-analysis concluded that bDMARDs have no significant effect on TLM.

Normative Data for Lean Mass and Fat Mass in Healthy Predominantly Breast-Fed Term Infants From 1 Month to 1 Year of Age

BACKGROUND

A leaner body phenotype in infancy plays an important role in the early life prevention of obesity. However, there is a dearth of reference data for body composition in infancy. This study aimed to create a normative reference dataset for lean (LM) and fat (FM) mass and accretion rates in healthy infants.

METHODS

Healthy term-born infants (35 boys; 35 girls) were studied at ≤ 1, 3, 6, 9, and 12 mo of age for growth and compared to World Health Organization standards. LM (g) and FM (g) were measured using DXA (APEX version 13.3:3, Hologic 4500A) in infant whole-body mode. Sex specific reference curves were generated using the LMS method (LMSchartmaker, Medical Research Council, UK).

RESULTS

Infants were predominantly white (82.9%), breastfed (98.4% ≥ 3 mo), and grew in length and weight within World Health Organization Z-score ranges for normal growth across infancy. LM accretion was 327.4 ± 12.5 g/mo representing 95% increment in LM. Boys had more LM compared to girls at 12 mo (7807.4 ± 1114.0 vs 6817.4 ± 1016.1 g; p = 0.008). FM accretion was 114.3 ± 12.0 g/mo representing 114% increment in FM with no difference between the sexes.

CONCLUSIONS

This data, which is based on a healthy sample of infants, characterizes LM and FM accretion during the first year of life and will aid in the interpretation of body composition.

Is there a relation between pre-sarcopenia, sarcopenia, cachexia and osteoporosis in patients with ankylosing spondylitis?

Background

Osteoporosis is a well-known complication of ankylosing spondylitis (AS). However, data about body composition modifications and muscle performance showed conflicting results. The aim of the study was to determine the prevalence and risk factors of pre-sarcopenia, sarcopenia and cachexia in patients with AS and analyze its relationship with bone loss and symptomatic and severity parameters of the disease.

Methods

Sixty-seven consecutive male patients with AS (mean age of 40.9 ± 11.0 years) and 67 healthy controls were studied. Body composition and bone mineral density (BMD) scans were obtained using DXA. The fat-free mass index (FFMI; fat-free mass divided by height squared) and the percent of fat mass (%FM) were calculated. Pre-sarcopenia was defined by low skeletal muscle mass (SMI <7.25 kg/m²), sarcopenia by the combined presence of the two following criteria: SMI <7.25 kg/m² and a low muscle strength (handgrip strength <30 kg) or a low muscle performance (timed get-up-and-go test >10 s) and cachexia by a BMI <20 kg/m² plus 3 from the 5 following parameters: anorexia, fatigue, handgrip strength <30 kg, CRP >5 mg/l, SMI <7.25 kg/m².

Results

Pre-sarcopenia, sarcopenia, cachexia, and osteoporosis prevalences were (50.4, 34.3, 11.9, and 16.0) respectively. Patients had a mean 3 kg significant decrease in FFM and a 1 kg/m² decrease in appendicular mass vs. healthy controls. Pre-sarcopenia, sarcopenia and cachexia were significantly associated to higher BASDAI levels and low BMD.

Conclusion

Our study showed that men with AS had a statistically significant reduction in total and appendicular lean mass that is related to higher disease activity and significantly associated to bone loss.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1155-z) contains supplementary material, which is available to authorized users.

Assessment of body composition in children with cerebral palsy: a cross-sectional study in Norway

AIM

The assessment of growth and body composition is challenging in children with cerebral palsy (CP). The aim of this study was to compare clinical assessments of body composition with measurements obtained using dual-energy X-ray absorptiometry (DXA) in this population.

METHOD

Knee height, weight, and triceps and subscapular skinfold thickness (SFT) were measured in 47 children with CP (age range 8-18y; 18 females, 29 males). Height was estimated from knee height, and used to calculate body mass index (BMI). Using SFT measurements, body fat percentage was calculated by standard ('Slaughter') and CP-modified ('Gurka') equations and compared with results obtained using DXA.

RESULTS

Children with severe gross motor function impairments (Gross Motor Function Classification System [GMFCS] level III or IV) exhibited stunted growth and had higher fat percentages and lower lean body mass than children classified in GMFCS level I or II. In 10 children classified as 'thin' according to their BMI (five of whom were assigned thinness grade of 2 or lower), percentage of body fat, as determined by DXA, was normal or high. The Slaughter equations significantly underestimated body fat percentages, whereas the precision of the CP-modified Gurka equations was excellent.

INTERPRETATION

In this study, children with CP and severe motor impairments displayed stunted growth, but were not undernourished. Relying solely upon BMIs may be misleading in children with CP. Therefore, clinicians should be encouraged to measure SFT and to calculate body fat percentages using the CP-modified version of the Slaughter equation.

Normative data for bone mass in healthy term infants from birth to 1 year of age

For over 2 decades, dual-energy X-ray absorptiometry (DXA) has been the gold standard for estimating bone mineral density (BMD) and facture risk in adults. More recently DXA has been used to evaluate BMD in pediatrics. However, BMD is usually assessed against reference data for which none currently exists in infancy. A prospective study was conducted to assess bone mass of term infants (37 to 42 weeks of gestation), weight appropriate for gestational age, and born to healthy mothers. The group consisted of 33 boys and 26 girls recruited from the Winnipeg Health Sciences Center (Manitoba, Canada). Whole body (WB) as well as regional sites of the lumbar spine (LS 1-4) and femur was measured using DXA (QDR 4500A, Hologic Inc.) providing bone mineral content (BMC) for all sites and BMD for spine. During the year, WB BMC increased by 200% (76.0 ± 14.2 versus 227.0 ± 29.7 g), spine BMC by 130% (2.35 ± 0.42 versus 5.37 ± 1.02 g), and femur BMC by 190% (2.94 ± 0.54 versus 8.50 ± 1.84 g). Spine BMD increased by 14% (0.266 ± 0.044 versus 0.304 ± 0.044 g/cm(2)) during the year. This data, representing the accretion of bone mass during the first year of life, is based on a representative sample of infants and will aid in the interpretation of diagnostic DXA scans by researchers and health professionals.

Revised pediatric reference data for the lateral distal femur measured by Hologic Discovery/Delphi dual-energy X-ray absorptiometry

Lateral distal femur (LDF) scans by dual-energy X-ray absorptiometry (DXA) are often feasible in children for whom other sites are not measurable. Pediatric reference data for LDF are not available for more recent DXA technology. The objective of this study was to assess older pediatric LDF reference data, construct new reference curves for LDF bone mineral density (BMD), and demonstrate the comparability of LDF BMD to other measures of BMD and strength assessed by DXA and by peripheral quantitative computed tomography (pQCT). LDF, spine and whole body scans of 821 healthy children, 5-18 yr of age, recruited at a single center were obtained using a Hologic Discovery/Delphi system (Hologic, Inc., Bedford, MA). Tibia trabecular and total BMD (3% site), cortical geometry (38% site) (cortical thickness, section modulus, and strain-strength index) were assessed by pQCT. Sex- and race-specific reference curves were generated using LMS Chartmaker (LMS Chartmaker Pro, version 2.3. Tim Cole and Huiqi Pan. Copyright 1997-2006, Medical Research Council, UK) and Z-scores calculated and compared by correlation analysis. Z-scores for LDF BMD based on published findings demonstrated overestimation or underestimation of the prevalence of low BMD-for-age depending on the region of interest considered. Revised LDF reference curves were generated. The new LDF Z-scores were strongly and significantly associated with weight, body mass index, spine and whole body BMD Z-scores, and all pQCT Z-scores. These findings demonstrate the comparability of LDF measurements to other clinical and research bone density assessment modes, and enable assessment of BMD in children with disabilities, who are particularly prone to low trauma fractures of long bones, and for whom traditional DXA measurement sites are not feasible.

Well-nourished cystic fibrosis patients have normal mineral density, but reduced cortical thickness at the forearm

Our goal was to assess mineral density and geometry of the cortex at the level of the forearm in adolescents and young adults with cystic fibrosis, using peripheral quantitative computed tomography. We found that density was normal, but cortical thickness significantly reduced, as well in males as in females.

INTRODUCTION

Our goal was to measure bone mineral density as a volumetric density, as well as total cross-sectional area, cortical area and cortical thickness, using peripheral quantitative computed tomography (pQCT) at the forearm in adolescents and young adults with cystic fibrosis. We evaluated relationships between forearm bone measurements and body composition assessed using dual energy X-ray absorptiometry (DXA).

METHODS

An XCT 2000 pQCT (Stratec, Pforzheim, Germany) and a QDR 4500 A-upgraded to Discovery DXA device (Hologic, Waltham, MA, USA) were used.

RESULTS

Forty-eight patients (31 males,17 females, mean+/-SD 20+/5 years) were studied. Anthropometric features were: height 169+/- 10 cm, SDS 0.05+/-0.12, body mass index 19.8+/- 2.5 kg/m(2), SDS -0.56+/-0.14. Bone mineral density and total cross-sectional area of the forearm and body composition were normal, whereas cortical thickness was significantly reduced in males (mean Z-score - 1.22, p < 0.05), and in females (mean Z-score - 1.61, p < 0.05). Total body lean mass correlated more strongly with cortical thickness (r = 0.72, p < 0.001) than with total bone mineral density at the proximal radius (r = 0.39, p < 0.05).

CONCLUSIONS

Adolescents and young adults with cystic fibrosis, presenting with only a slight degree of underweight, have at the radius a preserved bone mineral density but a reduced cortical thickness.

Growth and nutrition disorders in children with cerebral palsy

Growth and nutrition disorders are common secondary health conditions in children with cerebral palsy (CP). Poor growth and malnutrition in CP merit study because of their impact on health, including psychological and physiological function, healthcare utilization, societal participation, motor function, and survival. Understanding the etiology of poor growth has led to a variety of interventions to improve growth. One of the major causes of poor growth, malnutrition, is the best-studied contributor to poor growth; scientific evidence regarding malnutrition has contributed to improvements in clinical management and, in turn, survival over the last 20 years. Increased recognition and understanding of neurological, endocrinological, and environmental factors have begun to shape care for children with CP, as well. The investigation of these factors relies on advances made in the assessment methods available to address the challenges inherent in measuring growth in children with CP. Descriptive growth charts and norms of body composition provide information that may help clinicians to interpret growth and intervene to improve growth and nutrition in children with CP. Linking growth to measures of health will be necessary to develop growth standards for children with CP in order to optimize health and well-being.

Preliminary evidence for cachexia in patients with well-established ankylosing spondylitis

OBJECTIVES

Cachexia, defined as an accelerated loss of skeletal muscle in the context of a chronic inflammatory response, is common in rheumatoid arthritis but it has not been demonstrated in patients with ankylosing spondylitis (AS). The aim of this study was to determine muscle wasting and its functional consequences in a group of patients with well-established AS.

METHODS

Nineteen male patients (mean age 53 yrs) with long-standing AS (mean disease duration 19 yrs) and radiological changes (84% had one or more syndesmophytes) were compared with 19 age-matched healthy males with similar levels of habitual physical activity. Body composition was assessed by dual energy X-ray absorptiometry. Muscle strength was measured by isokinetic knee extension and hand grip dynamometry, and by 30 s arm curl and chair sit-to-stand tests.

RESULTS

AS patients showed a statistically and clinically significant 12% reduction in arms and legs lean mass, a proxy measure of total body skeletal muscle mass, compared with healthy controls (P < 0.05). This muscle loss was significantly associated with reduced upper and lower body strength (correlation coefficients ranging between 0.37 and 0.79, P < 0.05).

CONCLUSION

These results provide preliminary evidence that cachexia is a functionally relevant systemic complication of AS, particularly in patients with long-standing disease and radiological changes. Progressive resistance training and other interventions aimed at stimulating skeletal muscle growth might be beneficial in this population, and further studies on the pathophysiology of cachexia in AS patients are needed.

Reproducibility of pediatric whole body bone and body composition measures by dual-energy X-ray absorptiometry using the GE Lunar Prodigy

The use of dual-energy X-ray absorptiometry (DXA) in pediatrics is increasing. It is safe, readily available, and easily performed, but there is little information on reproducibility. The aim of this study is to evaluate the reproducibility of whole body DXA scans in children. Total and regional bone mineral density, bone mineral content, nonbone, lean fat mass, and percent fat were measured twice by whole body DXA (GE Lunar Prodigy) in 49 subjects (5 to 17 yr). Within each subject, between subjects, and reading standard deviations for each body component were evaluated as well as intraclass correlations (IC) and coefficients of variation (CV). Total body measurements had better IC and CV than regional results from the whole body scan, with legs and arms better than trunk and spine. IC values were >or=0.989 for total body, >or=0.976 for legs and arms, and >or=0.875 for trunk and spine. CV values ranged 0.18 to 1.97% for total body, and 0.96 to 6.91% for regional measures. These values confirm that body composition and bone mass by DXA are highly reproducible among pediatric subjects. The results of this study can be used by clinicians and researchers for interpretation of longitudinal observations and for power calculations.

Empirically derived new equations for calculating body fat percentage based on skinfold thickness and midarm circumference in preschool Indian children

We wanted to develop and apply new equations based on skinfold and midarm measurements for estimating %fat in preschool children suitable for field use. Prediction equations were developed on preschool-aged urban boys (n = 100) and girls (n = 84). Skinfolds at four sites and midarm measurements were regressed on %fat derived from equations based on height and weight and from bioelectrical impedance analysis (BIA; resistance at 50 kHz). These equations were applied: 1) to 12 children in whom the %fat was determined using D2O dilution, and 2) to 50 children in whom their %fat was derived using height-weight and BIA equations. The 95% limits of agreement (mean +/- 2 SD) for %fat derived by anthropometry and by new equations were within 1.7% in boys (r = 0.85; P < 0.001) and girls (r = 0.90; P < 0.001) and by BIA and new equations were within 1.5% in boys (r = 0.82; P < 0.001) and 2% in girls (r = 0.88; P < 0.001). For %fat measured by D2O dilution and new equations, 95% limits of agreement was within 1.3% (r = 0.98; P < 0.001). In 50 children 95% limits of agreement between anthropometry and new equations were within 1.8% in boys (r = 0.88; P < 0.001) and 1.4% in girls (r = 0.92; P < 0.001) and between BIA and new equations were within 1% in boys (r = 0.91; P < 0.001) and 1.5% in girls (r = 0.89; P < 0.001). The new equations for measuring %fat based on midarm circumference and skinfold measurements are rapid and accurate for South Asian children and should be useful for prediction of body composition and nutritional survey in field studies.

Lean body mass in preschool aged urban children in India: gender difference

OBJECTIVE

To estimate lean body mass (LBM) in preschool aged boys and girls in India and explore gender difference.

DESIGN

Crossectional.

SETTING

Immunization clinic of a charitable Government General Hospital in Kolkata, India.

SUBJECTS

Two-hundred and forty-five children (147 boys and 98 girls) aged 1-5 y from among the urban poor were admitted in the study between July 1999 and December 2000. Children with acute or chronic illness or congenital malformation were excluded.

METHOD

Length/height to the nearest 0.1 cm, weight to the nearest 10 g and total body resistance using multifrequency bioelectrical (Xitron 4000B) impedance analyzer (BIA) at 50 kHz were measured. Their nutritional status was compared with National Center for Health Statistics (NCHS) median data and lean body mass (LBM) was calculated using anthropometry and BIA equations. The groups were compared using analysis of variance and multiple linear regression.

RESULTS

Girls were more stunted (P<0.001) and underweight (P<0.047), while the degree of wasting was similar. Mean LBM percentage was higher in boys compared with girls by anthropometry (P<0.001) and BIA (P<0.005), which persisted after adjusting for age. With increasing age, LBM percentage declined in girls (P<0.02) in contrast to reference girls, in whom it increased. In boys LBM percentage increased with age as is in reference boys.

CONCLUSIONS

In addition to the girls being more stunted and underweight, LBM% decreased in girls with increasing age but steadily increased in boys, suggesting hidden deprivation of female children.