Nutritional dwarfing: growth,dieting, and fear of obesity.

Objective: Current methods for measuring regional body fat are expensive and inconvenient compared to the relative cost-effectiveness and ease of use of a stereovision body imaging (SBI) system. The primary goal of this research is to develop prediction models for android and gynoid fat by body measurements assessed via SBI and dual-energy x-ray absorptiometry (DXA). Subsequently, mathematical equations for prediction of total and regional (trunk, leg) body adiposity were established via parameters measured by SBI and DXA.

Methods: A total of 121 participants were randomly assigned into primary and cross-validation groups. Body measurements were obtained via traditional anthropometrics, SBI, and DXA. Multiple regression analysis was conducted to develop mathematical equations by demographics and SBI assessed body measurements as independent variables and body adiposity (fat mass and percentage fat) as dependent variables. The validity of the prediction models was evaluated by a split sample method and Bland-Altman analysis.

Results: The R² of the prediction equations for fat mass and percentage body fat were 93.2% and 76.4% for android and 91.4% and 66.5% for gynoid, respectively. The limits of agreement for the fat mass and percentage fat were ?0.06 ± 0.87 kg and ?0.11% ± 1.97% for android and ?0.04 ± 1.58 kg and ?0.19% ± 4.27% for gynoid. Prediction values for fat mass and percentage fat were 94.6% and 88.9% for total body, 93.9% and 71.0% for trunk, and 92.4% and 64.1% for leg, respectively.

Conclusions: The three-dimensional (3D) SBI produces reliable parameters that can predict android and gynoid as well as total and regional (trunk, leg) fat mass.     

The body fat-cognition relationship in healthy older individuals: Does gynoid vs android distribution matter?

Objective

To examine the relationship between regional and whole body fat accumulation and core cognitive executive functions.

Design

Cross-sectional study.

Settings and participants

78 healthy men and women aged between 65 and 75 years recruited through consumer’s database.

Measurements

DXA measured percentage total body fat, android, gynoid distribution and android/gynoid ratio; inhibition and working memory updating through Random Number Generation test and cognitive flexibility by Trail Making test. First-order partial correlations between regional body fat and cognitive executive function were computed partialling out the effects of whole body fat. Moderation analysis was performed to verify the effect of gender on the body fat-cognition relationship.

Results

Results showed a differentiated pattern of fat-cognition relationship depending on fat localization and type of cognitive function. Statistically significant relationships were observed between working memory updating and: android fat (r = -0.232; p = 0.042), gynoid fat (r = 0.333; p = 0.003) and android/gynoid ratio (r = -0.272; p = 0.017). Separating genders, the only significant relationship was observed in females between working memory updating and gynoid fat (r = 0.280; p = 0.045). In spite of gender differences in both working memory updating and gynoid body fat levels, moderation analysis did not show an effect of gender on the relationship between gynoid fat and working memory updating.

Conclusions

Results suggest a protective effect of gynoid body fat and a deleterious effect of android body fat. Although excessive body fat increases the risk of developing CDV, metabolic and cognitive problems, maintaining a certain proportion of gynoid fat may help prevent cognitive decline, particularly in older women. Guidelines for optimal body composition maintenance for the elderly should not target indiscriminate weight loss, but weight maintenance through body fat/lean mass control based on non-pharmacological tools such as physical exercise, known to have protective effects against CVD risk factors and age-related cognitive deterioration.

     

Associations of Serum Carotenoids with DXA-Derived Body Fat and Fat Distribution in Chinese Adults: A Prospective Study

BackgroundMost previous studies have examined the associations between carotenoids and anthropometrics with cross-sectional designs. Few studies have investigated the associations between serum carotenoids and fat mass and fat distribution (general vs central type).ObjectiveThis study aimed to explore the associations of serum carotenoids with body fat and fat distribution in Chinese adults.DesignCross-sectional and longitudinal analyses of a prospective, community-based cohort were performed.Participants/settingThere were 4,048 participants aged 40 to 75 years recruited in the Guangzhou Nutrition and Health Study from 2008 to 2013.Main outcome measuresSerum carotenoids were assessed at baseline. Anthropometrics, fat mass (FM), and percentage FM (%FM) over the total body, trunk, limbs, and android and gynoid regions were obtained by dual-energy x-ray absorptiometry for 3,002 participants between 2011 and 2013 and for 2,537 participants after 3.1 years.Statistical analysisCross-sectional and longitudinal analyses were performed to compare the mean differences in adiposity indices among the quartiles of carotenoids.ResultsCovariance analyses showed significant inverse associations between serum total carotenoid levels and adiposity indices cross-sectionally (all P trends<0.05). The percentage mean differences in quartile 4 (vs 1) in FM and %FM were much more pronounced in the trunk (–15.4% and –7.74%) and android area (–16.6% and –8.59%) than those in the limbs (–8.31% and –4.51%) and gynoid area (–7.76% and –2.71%) (all P<0.001). Longitudinal results revealed that higher total carotenoids were associated with significantly lower 3-year increases in body mass index (calculated as kg/m²); waist circumference; waist-to-hip ratio; body FM in the limbs and android and gynoid area; and %FM in total body, trunk, and limbs (all P trends<0.05). Regarding individual carotenoids, β-carotene tended to have the most notable beneficial associations with the majority of fat indices, especially for cross-sectional analyses.ConclusionsSerum carotenoid concentrations are inversely associated with body fat, especially in the abdominal region, in Chinese adults.     

Bone and Body Composition Measurements of Small Subjects: Discrepancies from Software for Fan-Beam Dual Energy X-Ray Absorptiometry

Objectives: A piglet model was used to determine the variations in measurements from different software algorithms used in the same type of dual energy X ray absorptiometry (DXA) instruments from the same manufacturer.

Methods: Forty-one piglets (6190 +/? 5856g, mean +/? SD) were scanned in duplicate with a fan-beam densitometer (Hologic QDR4500A, Hologic Inc, Bedford, MA) in the infant whole body scan mode. The same scans were analyzed with two software versions: vKH6 (validated with carcass chemical measurement) and v11.2 (commercial software from the same densitometer manufacturer).

Results: All analysis values were highly correlated (r = 0.90 to 1.00) and DXA values for total weights were almost identical. However, v11.2 results consistently overestimated bone mineral content (49.3 +/? 23.4%, mean +/? SD), bone area (21.1 +/? 8.2%), bone mineral density (24.1 +/? 22.2%), and fat mass (160.9 +/? 71.7%) but underestimated lean mass (?14.3 +/? 5.5%) when compared to the values from vKH6. Differences between software versions increased with heavier piglets.

Conclusion: The commercial software for fan-beam DXA measurement of piglets, matched for the size of human infants and young children, has major inaccuracies for bone mineral and body composition that become further exaggerated with increasing weight of the subject.     

Precision of total and regional body fat estimates from dualenergy X-ray absorptiometer measurements

Objectives: To evaluate the precision of both total %fat and all the regional %fat measures acquired from both the Lunar Prodigy and Lunar iDXA software. Design: Cross-sectional study. Setting: University-based research laboratory. Participants: The sample consisted of 300 individual test records from men and women who had volunteered to participate in dual-energy x-ray absorptiometer (DXA) technician precision training studies. Subjects ranged in age from 20–84 years and in body mass index from 15.7–52.0 kg.m^?2. Measurements: A total of 27 different technicians performed three total body scan measurements on 10–15 different subjects. The Lunar Prodigy and Lunar iDXA were used for 253 and 47 precision training evaluations, respectively. The regions of interest (ROI) were automatically determined by the enCORE software (autoROI) for total body, android, gynoid, trunk, legs, and arms regions and the region %fat data were used for analyses. Results: The CV for total body %fat was 1.9% and 0.9% for the Prodigy and iDXA, respectively. CV’s for %fat measures at regional sites ranged from 1.2–4.4% for the Prodigy measures and 0.9–2.4% for the iDXA measures. The ICC for both devices ranged from 0.990 to 0.999. Conclusion: Monitoring the status of body composition changes with age is gaining more clinical acceptance. Thus, it is important that practitioners use measures that are both precise and accurate. The findings from the current study add support that DXA measurements can be used with a high level of confidence for serial testing of patients.     

Phantoms for Cross-Calibration of Dual Energy X-ray Absorptiometry Measurements in Infants

Objective: To test the suitability of phantoms to cross-calibrate body composition measurements in small subjects among different dual energy X-ray absorptiometry (DXA) instruments.

Methods: A set of four phantoms with total weights 1520g, 3140g, 4650g and 7490g were made with low cost and easily available materials. Each phantom was made from assembling polyethylene bottles (100 to 1000 mL) filled with either pure olive oil or electrolyte solution in different combinations, and borosilicate tubes (3 and 5 mL) and flexible polypropylene tubing filled with calcium carbonate. Triplicate measurements of each of the four phantoms were performed with three pencil beam densitometers made by the same manufacturer (Hologic Inc., Waltham, MA): two QDR 2000 (University of Liege, Liege, Belgium, and Wayne State University, Detroit, Michigan) and a QDR1500 (University Children’s Hospital, Greifswald, Germany) using infant whole body-scanning mode and analyzed with software V5.73P.

Results: DXA measured total weight, or bone, lean and fat masses, from one center were highly predictive of DXA measurements from the other centers with an adjusted r² of 0.94 to 1.00, p < 0.001. This was the case whether the measurements from single scan or from average of triplicate scans were used in the analysis.

Conclusions: Systematic corrections, in the form of linear transformations, are possible to allow comparison of clinical data generated from different centers. Different size phantoms can be made to accommodate the varying range of weights and body composition of study subjects.     

Increased consumption of dairy foods and protein during diet- and exercise-induced weight loss promotes fat mass loss and lean mass gain in overweight and obese premenopausal women

Weight loss can have substantial health benefits for overweight or obese persons; however, the ratio of fat:lean tissue loss may be more important. We aimed to determine how daily exercise (resistance and/or aerobic) and a hypoenergetic diet varying in protein and calcium content from dairy foods would affect the composition of weight lost in otherwise healthy, premenopausal, overweight, and obese women. Ninety participants were randomized to 3 groups (n = 30/group): high protein, high dairy (HPHD), adequate protein, medium dairy (APMD), and adequate protein, low dairy (APLD) differing in the quantity of total dietary protein and dairy food-source protein consumed: 30 and 15%, 15 and 7.5%, or 15 and <2% of energy, respectively. Body composition was measured by DXA at 0, 8, and 16 wk and MRI (n = 39) to assess visceral adipose tissue (VAT) volume at 0 and 16 wk. All groups lost body weight (P < 0.05) and fat (P < 0.01); however, fat loss during wk 8-16 was greater in the HPHD group than in the APMD and APLD groups (P < 0.05). The HPHD group gained lean tissue with a greater increase during 8-16 wk than the APMD group, which maintained lean mass and the APLD group, which lost lean mass (P < 0.05). The HPHD group also lost more VAT as assessed by MRI (P < 0.05) and trunk fat as assessed by DXA (P < 0.005) than the APLD group. The reduction in VAT in all groups was correlated with intakes of calcium (r = 0.40; P < 0.05) and protein (r = 0.32; P < 0.05). Therefore, diet- and exercise-induced weight loss with higher protein and increased dairy product intakes promotes more favorable body composition changes in women characterized by greater total and visceral fat loss and lean mass gain.     

Exercise Training Combined with Calanus Oil Supplementation Improves the Central Cardiodynamic Function in Older Women

The aim of this study was to investigate the possible beneficial effects of exercise training (ET) with omega-3/Calanus oil supplementation on cardiorespiratory and adiposity parameters in elderly women. Fifty-five women (BMI: 19–37 kg/m², 62–80 years old) were recruited and randomly assigned to the 4 month intervention with ET and omega-3 supplementation (Calanus oil, ET-Calanus) or ET and the placebo (sunflower oil; ET-Placebo). The body composition was determined by dual-energy X-ray absorptiometry (DXA), and cardiorespiratory parameters were measured using spiroergometry and PhysioFlow hemodynamic testing. Both interventions resulted in an increased lean mass whereas the fat mass was reduced in the leg and trunk as well as the android and gynoid regions. The content of trunk fat (in percent of the total fat) was lower and the content of the leg fat was higher in the ET-Calanus group compared with the ET-Placebo. Although both interventions resulted in similar improvements in cardiorespiratory fitness (VO_2max), it was explained by an increased peripheral oxygen extraction (a-vO₂diff) alone in the ET-Placebo group whereas increased values of both a-vO₂diff and maximal cardiac output (CO_max) were observed in the ET-Calanus group. Changes in CO_max were associated with changes in systemic vascular resistance, circulating free fatty acids, and the omega-3 index. In conclusion, Calanus oil supplementation during a 4 month ET intervention in elderly women improved the cardiorespiratory function, which was due to combined central and peripheral cardiodynamic mechanisms.     

Validation of bone mass and body composition measurements in small subjects with pencil beam dual energy X-ray absorptiometry

OBJECTIVE: To validate the most widely reported dual energy X-ray absorptiometry (DXA) technique for the measurement of bone mass and body composition in human infants with a piglet model. METHODS: Duplicate scans were obtained in 13 piglets (1950g to 21100g) using a whole body densitometer (Hologic QDR 2000 plus, Hologic Inc., Waltham, MA) operated in the pencil-beam mode on a two platform (aluminum platform overlying a foam table pad) system. DXA measurements that included total weight, bone mineral content, fat and lean mass were compared with carcass weight and chemical analysis for ash and calcium content, fat and lean mass. RESULTS: Measurements from duplicate DXA scans were nearly perfectly correlated (r = 0.98 to 1.00). DXA measurements were strongly predictive of scale weight and chemical composition for all piglets (adjusted r(2) = 0.93 to 1.00, intraclass reliability coefficients = 0.943 to 0.999, p < 0.001 for all comparisons) although DXA bone mineral content consistently underestimated carcass ash and calcium content. Measured values from heavier piglets were not significantly different from values predicted from the lighter piglets' data. Slopes from regression based on lighter versus heavier piglets were not significantly different except for the bone mineral content with carcass ash or calcium content. CONCLUSION: Our study validated the use of pencil beam DXA and its ability to determine relative changes in bone mass and body composition measurements over a much greater range of body weight than previous reports although its use as a direct indicator of nutrient requirement may be limited.     

Impact of Abdominal Adipose Depots and Race on Risk for Colorectal Cancer: A Case-Control Study

Visceral adipose tissue (VAT) but not subcutaneous adipose tissue (SAT) is associated with obesity-related diseases including colorectal cancer (CRC). Superficial SAT (SSAT) and deep SAT (DSAT), components of SAT, also appear to independently influence disease risk. These abdominal adipose tissues (AATs) are not extensively studied in connection with CRC and have not been explored in the United States despite known racial variations in body composition. We conducted a case-control study that compared associations between AAT with CRC risk and race of African-American (AA) and non-Hispanic white (NHW) men with incident CRC matched by age, body mass index, and race (N = 158, 79/group). Cross-sectional computed tomography images were used for assessment of AAT. Overall cases and controls had similar VAT areas (140 ± 192 vs 149 ± 152 cm², P-value = 0.93); however, cases had lower SSAT than controls (88 ± 39 vs 112 ± 65 cm², P < 0.01). Among controls, AA had significantly lower VAT (114 ± 168 vs 180 ± 167, P < 0.01) than NHW. Conditional logistic regression revealed that AA men with greater SSAT had lower odds for CRC (odds ratio [OR]: 0.24, 95% confidence interval [CI] 0.07–0.85). Our findings indicate that VAT does vary between cases and controls by race; however, this variation is not a risk factor for CRC. The negative association between CRC and SSAT in AA men warrants further investigation.     

Comparison of regional fat distribution and health risk factors in middle-aged white and African American women: The Healthy Transitions Study

OBJECTIVE: Both ethnicity and menopause appear to influence intra-abdominal fat distribution. This study evaluated intra-abdominal fat distribution and obesity-related health risks in perimenopausal white and African American women. RESEARCH METHODS AND PROCEDURES: Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis. RESULTS: African American women were slightly younger (46.7 +/- 0.2 vs. 47.7 +/- 0.2 years, p = 0.002) and fatter (42.4% +/- 1.0% vs. 39.4% +/- 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT, although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites. CONCLUSIONS: Middle-aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.     

Body Fat Distribution,Glucose Metabolism,and Diabetes Status Among Older Adults: The Multiethnic Cohort Adiposity Phenotype Study

BackgroundAs the proportion of visceral (VAT) to subcutaneous adipose tissue (SAT) may contribute to type 2 diabetes (T2D) development, we examined this relation in a cross-sectional design within the Multiethnic Cohort that includes Japanese Americans known to have high VAT. The aim was to understand how ectopic fat accumulation differs by glycemic status across ethnic groups with disparate rates of obesity, T2D, and propensity to accumulate VAT.MethodsIn 2013–2016, 1,746 participants aged 69.2 (standard deviation, 2.7) years from five ethnic groups completed questionnaires, blood collections, and whole-body dual X-ray absorptiometry and abdominal magnetic resonance imaging scans. Participants with self-reported T2D and/or medication were classified as T2D, those with fasting glucose >125 and 100–125 mg/dL as undiagnosed cases (UT2D) and prediabetes (PT2D), respectively. Using linear regression, we estimated adjusted means of adiposity measures by T2D status.ResultsOverall, 315 (18%) participants were classified as T2D, 158 (9%) as UT2D, 518 (30%) as PT2D, and 755 (43%) as normoglycemic (NG), with significant ethnic differences (P < 0.0001). In fully adjusted models, VAT, VAT/SAT, and percent liver fat increased significantly from NG, PT2D, UT2D, to T2D (P < 0.001). Across ethnic groups, the VAT/SAT ratio was lowest for NG participants and highest for T2D cases. Positive trends were observed in all groups except African Americans, with highest VAT/SAT in Japanese Americans.ConclusionThese findings indicate that VAT plays an important role in T2D etiology, in particular among Japanese Americans with high levels of ectopic adipose tissue, which drives the development of T2D to a greater degree than in other ethnic groups.Key words: type 2 diabetes, body fat distribution, visceral fat, ethnicity     

Visceral Adipose Tissue Volume and the Occurrence of Colorectal Adenoma in Follow-up Colonoscopy for Screening and Surveillance

Whether obesity accelerates adenoma recurrence is not yet clear; therefore, we analyzed the risk factors for adenoma occurrence at follow-up colonoscopy, with a focus on visceral adiposity. In total, 1516 subjects underwent index colonoscopy, computed tomography, and questionnaire assessment from February to May 2008; 539 subjects underwent follow-up colonoscopy at the National Cancer Center at least 6 mo after the index colonoscopy. The relationships between the presence of adenoma at follow-up colonoscopy and anthropometric obesity measurements, including body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) volume, and subcutaneous adipose tissue (SAT) volume, were analyzed. 188 (34.9%) had adenomatous polyps at follow-up colonoscopy. Multivariate analysis revealed that VAT volume ≥ 1000 cm³ and BMI ≥ 30 kg/m² were related to the presence of adenoma at follow-up colonoscopy (VAT volume 1000–1500 cm³: odds ratio [OR] = 2.13(95% confidence interval, CI = 1.06–4.26), P = 0.034; VAT volume ≥ 1000 cm³: OR = 2.24(95% CI = 1.03–4.88), P = 0.043; BMI ≥ 30 kg/m²: OR = 4.22(95% CI = 1.12–15.93), P = 0.034). In contrast, BMI 25–29.9 kg/m², SAT volume, and WC were not associated with the presence of adenoma at follow-up colonoscopy. In conclusion, excess VAT can contribute to the development and growth of new colorectal adenomas, and is a better predictor of colorectal adenoma occurrence at follow-up colonoscopy than BMI, WC, and SAT volume.     

Visceral adipose tissue and body fat mass: Predictive values for and role of gender in cardiometabolic risk among Turks

ObjectiveWe investigated the predictive values of visceral adipose tissue area (VAT) and body fat mass for a composite endpoint consisting of type 2 diabetes and coronary heart disease and for incident metabolic syndrome.MethodsWe analyzed at 4-y follow-up 157 middle-aged men and women in whom body composition analyzer and single-scan computerized tomography had been used.ResultsSex- and age-adjusted mean areas of visceral fat were 1.5-fold greater in individuals with than without the composite endpoint (P < 0.001), whereas abdominal subcutaneous fat was similar. Analysis of receiver operating characteristics for the optimal criterion regarding the composite endpoint (in 37 participants) indicated a VAT of 130 cm² and accuracies of 60% in men and 85% in women. Whereas age-adjusted VAT alone significantly predicted the composite endpoint in men, body fat mass or VAT predicted it in women (with 2.2- to 2.6-fold relative risks for 1-SD increment). Age-adjusted incident metabolic syndrome was significantly predicted by each parameter in men but only by fat mass in women.ConclusionVisceral adiposity in men and body fat mass in women seem to be of greater relevance in cardiometabolic risk for the prediction of which 130 cm² of VAT in both sexes and/or 27 kg of fat mass in women are useful cutoffs. Sex differences may reflect the predominating role of visceral adiposity in men and of insulin resistance in women in this risk.     

Associations between Body Composition and Vitamin D Status in Children with Overweight and Obesity Participating in a 1-Year Lifestyle Intervention

Background: To examine associations between body composition and vitamin D status in children participating in a lifestyle intervention. Methods: Children (6–12 y, n = 101) with a body mass index (BMI)-for-age >85th percentile were randomized to six dietitian-led behavior counselling sessions or no intervention. Plasma 25-hydroxyvitamin D (25(OH)D), anthropometry, and body composition using dual-energy X-ray absorptiometry were assessed every 3 months for 1 year. For each anthropometry variable (z-scores), tertiles were created to test for differences in 25(OH)D over time (tertile-by-time), and for changes in the z-score (loss, maintain, gain)-by-time, and according to fat patterning (android vs. gynoid) using mixed effects models. Results: The baseline plasma 25(OH)D was 62.2 nmol/L (95%CI: 58.7–65.7), and none < 30 nmol/L. At 6 mo, children with gynoid fat patterning had higher 25(OH)D concentrations than in those with android fat patterning (64.5 ± 1.1 nmol/L vs. 50.4 ± 1.0 nmol/L, p < 0.003, Cohen’s f = 0.20). Children with the lowest lean mass index z-score at 9 mo had higher plasma 25(OH)D concentrations than children with the highest z-score at baseline, 3 mo, and 6 mo (p < 0.05, Cohen’s f = 0.20). No other significant differences were observed. Conclusion: In this longitudinal study, vitamin D deficiency was not present in children 6–12 y of age with obesity. Reductions in adiposity did not alter the vitamin D status.     

Fat-Free Mass Index as a Surrogate Marker of Appendicular Skeletal Muscle Mass Index for Low Muscle Mass Screening in Sarcopenia

ObjectivesWe aimed to examine the relationship between the fat-free mass index (FFMI; FFM/height²) and appendicular skeletal muscle mass index (ASMI; ASM/height²), measured using both bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), and investigate the effects of age and obesity. We also evaluated the suitability of BIA-measured FFMI as a simple surrogate marker of the ASMI and calculated the optimal FFMI cutoff value for low muscle mass screening to diagnose sarcopenia.DesignCross-sectional study.Setting and ParticipantsThis study included 1313 adults (women, 33.6%) aged 40-87 years (mean age, 55 ± 10 years) from the WASEDA’S Health Study.MethodsBody composition was measured using multifrequency BIA and DXA. Low muscle mass was defined according to the criteria of the Asian Working Group for Sarcopenia 2019.ResultsBIA-measured FFMI showed strong positive correlations with both BIA- (r = 0.96) and DXA-measured (r = 0.95) ASMIs. Similarly, in the subgroup analysis according to age and obesity, the FFMI was correlated with the ASMI. The areas under the receiver operating characteristic curve for screening low muscle mass defined by DXA-measured ASMI using BIA-measured FFMI values were 0.95 (95% CI 0.93-0.97) for men and 0.91 (95% CI 0.87-0.94) for women. The optimal BIA-measured FFMI cutoff values for screening low muscle mass defined by DXA-measured ASMI were 17.5 kg/m² (sensitivity 89%, specificity 88%) for men and 14.6 kg/m² (sensitivity 80%, specificity 86%) for women.Conclusions and ImplicationsThe FFMI showed a strong positive correlation with BIA- and DXA-measured ASMIs, regardless of age and obesity. The FFMI could be a useful simple surrogate marker of the ASMI for low muscle mass screening in sarcopenia in community settings. The suggested FFMI cutoff values for predicting low muscle mass are <18 kg/m² in men and <15 kg/m² in women.     

Assessment of Intramuscular Fat and Correlation with Body Composition in Patients with Rheumatoid Arthritis and Spondyloarthritis: A Pilot Study

Rheumatoid arthritis (RA) and spondyloarthritis (SpA) are associated with changes in body composition. Ectopic intramuscular fat (IMAT) may alter muscle function and contribute to cardiometabolic disorders. In a pilot study, we analyzed IMAT in the calf with peripheral quantitative computed tomography (pQCT) and examined correlations between IMAT quantity and body composition parameters. In 20 patients with active RA and 23 with active SpA, IMAT was correlated with visceral fat (VAT; r = 0.5143 and 0.6314, respectively; p < 0.05) and total lean mass (r = 0.5414 and 0.8132, respectively; p < 0.05), but not with whole body fat mass. Total lean mass mediated 16% and 33% of the effects of VAT on IMAT in RA and SpA, respectively. In both RA and SpA, calf muscle area was correlated with total lean mass (r = 0.5940 and r = 0.8597, respectively; p < 0.05) and fat area was correlated with total body fat (r = 0.6767 and 0.5089, respectively; p < 0.05) and subcutaneous fat (r = 0.6526 and 0.5524, respectively; p < 0.05). Fat area was inversely correlated with handgrip and walking tests, and it was associated with disease activity and disability. We showed that ectopic IMAT, measured with pQCT, was correlated with VAT, but not with total body fat, in RA and SpA. This result suggests that metabolically active fat was specifically associated with IMAT.     

TNFα blockade for inflammatory rheumatic diseases is associated with a significant gain in android fat mass and has varying effects on adipokines: a 2-year prospective study

Purpose

To evaluate the long-term consequences of TNFα inhibitors on body composition and fat distribution, as well as changes in serum adipokines in patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS).

Methods

Eight patients with RA and twelve with AS requiring a TNFα inhibitor were prospectively followed for 2 years. Body composition was evaluated by dual X-ray absorptiometry and included measurements of total fat mass, lean mass, fat in the gynoid and android regions, and visceral fat. Serum leptin, total and high molecular weight (HMW) adiponectin, resistin, and ghrelin were also assessed.

Results

There was a significant gain in body mass index (p = 0.05) and a tendency for weight (p = 0.07), android fat (p = 0.07), and visceral fat (p = 0.059) increase in patients with RA, while in AS, total fat mass significantly increased (p = 0.02) with a parallel weight gain (p = 0.07). When examining the whole population of patients, we observed after 2 years a significant increase in body weight (+1.9 %; p = 0.003), body mass index (+2.5 %; p = 0.004), total fat mass (+11.1 %; p = 0.007), and fat in the android region (+18.3 %; p = 0.02). There was a substantial, albeit nonsignificant gain in visceral fat (+24.3 %; p = 0.088). Lean mass and gynoid fat were not modified. No major changes were observed for serum leptin, total adiponectin, and ghrelin, while HMW adiponectin and the HMW/total adiponectin ratio tended to decrease (?15.2 %, p = 0.057 and ?9.3 %, p = 0.067, respectively). Resistin decreased significantly (?22.4 %, p = 0.01).

Conclusions

Long-term TNFα inhibition in RA and AS is associated with a significant gain in fat mass, with a shift to the android (visceral) region. This fat redistribution raises questions about its influence on the cardiovascular profile of patients receiving these treatments.     

Metabolic syndrome screening using visceral adipose tissue (VAT) from opportunistic MRI locations in a multi-ethnic population

ObjectiveTo determine if visceral adipose tissue (VAT) area measured through MRI can be used opportunistically to assess the presence of cardiometabolic risk factors and compare its performance to simpler adiposity measures.MethodsA cross-sectional analysis was carried out on a subset of 1683 participants (856 women) from the Adiposity Phenotype Study (mean age = 69.2y; range 59.9–77.4). The association of total VAT area (sum of four cross sections, L1–L2, L2–L3, L3–L4, L4–L5) and each location, as well as BMI and body fat % (per SD) with the metabolic syndrome (MetSx) or its components was evaluated through logistic regression analysis.ResultsTotal VAT can be accurately predicted using all sites evaluated (R² range = 0.82?0.96). In men, VAT did not show a superior association to MetSx compared to BMI in men. However, in women, VAT was consistently superior to BMI and body fat % in its association to MetSx, independent of ethnicity [odds ratio for BMI, body fat %and total VAT area = 2.25 (95% CI: 1.93–2.62); 1.66 (95% CI: 1.36–2.03); 6.20 (95% CI: 4.69–8.21) respectively in all women]. Ethnic-specific odds ratios to MetSx in women ranged from 5.38 to 8.63 for total VAT area and 2.12–4.08 for BMI.ConclusionTotal VAT area can be accurately predicted from individual VAT regions in men and women and offers superior association to BMI for MetSx in women but not in men for five ethnicities. Therefore, opportunistic screening for elevated VAT area in women may be warranted across multiple ethnic groups.     

Bone and body composition measurements of small subjects: discrepancies from software for fan-beam dual energy X-ray absorptiometry

OBJECTIVES: A piglet model was used to determine the variations in measurements from different software algorithms used in the same type of dual energy X ray absorptiometry (DXA) instruments from the same manufacturer. METHODS: Forty-one piglets (6190 +/- 5856g, mean +/- SD) were scanned in duplicate with a fan-beam densitometer (Hologic QDR4500A, Hologic Inc, Bedford, MA) in the infant whole body scan mode. The same scans were analyzed with two software versions: vKH6 (validated with carcass chemical measurement) and v11.2 (commercial software from the same densitometer manufacturer). RESULTS: All analysis values were highly correlated (r = 0.90 to 1.00) and DXA values for total weights were almost identical. However, v11.2 results consistently overestimated bone mineral content (49.3 +/- 23.4%, mean +/- SD), bone area (21.1 +/- 8.2%), bone mineral density (24.1 +/- 22.2%), and fat mass (160.9 +/- 71.7%) but underestimated lean mass (-14.3 +/- 5.5%) when compared to the values from vKH6. Differences between software versions increased with heavier piglets. CONCLUSION: The commercial software for fan-beam DXA measurement of piglets, matched for the size of human infants and young children, has major inaccuracies for bone mineral and body composition that become further exaggerated with increasing weight of the subject.