Health and ageing: a cross-sectional study of body composition

Artificial intelligence-based body composition analysis using computed tomography images predicts both prevalence and incidence of diabetes mellitus

AIM/INTRODUCTION

We assess the efficacy of artificial intelligence (AI)-based, fully automated, volumetric body composition metrics in predicting the risk of diabetes.

MATERIALS AND METHODS

This was a cross-sectional and 10-year retrospective longitudinal study. The cross-sectional analysis included health check-up data of 15,330 subjects with abdominal computed tomography (CT) images between January 1, 2011, and September 30, 2012. Of these, 10,570 subjects with available follow-up data were included in the longitudinal analyses. The volume of each body segment included in the abdominal CT images was measured using AI-based image analysis software.

RESULTS

Visceral fat (VF) proportion and VF/subcutaneous fat (SF) ratio increased with age, and both strongly predicted the presence and risk of developing diabetes. Optimal cut-offs for VF proportion were 24% for men and 16% for women, while VF/SF ratio values were 1.2 for men and 0.5 for women. The subjects with higher VF/SF ratio and VF proportion were associated with a greater risk of having diabetes (adjusted OR 2.0 [95% CI 1.7-2.4] in men; 2.9 [2.2-3.9] in women). In subjects with normal glucose tolerance, higher VF proportion and VF/SF ratio were associated with higher risk of developing prediabetes or diabetes (adjusted HR 1.3 [95% CI 1.1-1.4] in men; 1.4 [1.2-1.7] in women). These trends were consistently observed across each specified cut-off value.

CONCLUSIONS

AI-based volumetric analysis of abdominal CT images can be useful in obtaining body composition data and predicting the risk of diabetes.

Impact of daily fasting duration on body composition and cardiometabolic risk factors during a time-restricted eating protocol: a randomized controlled trial

BACKGROUND

Time-restricted eating (TRE) is a dietary regimen that limits food intake for at least 12 h daily. Unlike other fasting protocols, TRE does not dictate what or how much to eat but rather focuses on the timing of meals. This approach has been previously demonstrated to improve body composition in individuals with obesity or metabolic impairments. However, its impact on body composition and cardiometabolic factors in healthy individuals remains unclear. Furthermore, the optimal fasting duration is still debated. Thus, we aimed to compare the effects of 8 weeks of different fasting durations on body composition and biochemical parameters in metabolically healthy, non-trained individuals using a parallel randomized controlled trial.

METHODS

Forty-one volunteers were randomly assigned to one of the four experimental groups: TRE 16:8 (16 h of fasting,8 h of eating), TRE 14:10 (14 h of fasting,10 h of eating), TRE 12:12 (12 h of fasting,12 h of eating) or a normal diet group (ND; no dietary restriction). Participants underwent body composition measurements and blood tests for lipid profiles (i.e., total cholesterol, LDL, HDL, and triglycerides), fasting glucose, leptin, and anabolic hormones (i.e., insulin and testosterone) levels. Data were analyzed using both intention-to-treat (ITT) and per-protocol (PP) analysis to account for compliance. A two-way ANOVA for repeated measures was employed to assess interactions between time and group.

RESULTS

In the ITT analysis, TRE 16:8 reduced body mass (-2.46%, p = 0.003) and absolute fat mass (-8.65%, p = 0.001) with no changes in lean soft tissue and in calorie intake. These results were consistent with the PP analysis which included 8 participants in TRE 16:8, 5 in TRE 14:10, 9 in TRE 12:12, and the entire ND group. Participants in the TRE 16:8 group spontaneously reduced their total caloric intake, although this reduction was not statistically significant. None of the other measurements significantly changed after 8 weeks.

CONCLUSIONS

Our results suggest that a 16-hour fasting window, even without caloric restriction, may be a viable strategy for improving body composition in healthy and non-trained individuals, whereas a shorter fasting period may be insufficient to produce significant changes in a healthy population.

TRIAL REGISTRATION

NCT, NCT04503005. Registered 4 August 2020, https://clinicaltrials.gov/study/NCT04503005 .

Impact of Visceral and Hepatic Fat on Cardiometabolic Health

PURPOSE OF REVIEW

Body fat distribution plays a significant role in the cardiometabolic consequences of obesity. We review the impact of visceral and hepatic fat and highlight important interventions.

RECENT FINDINGS

Several epidemiologic studies have established a clear association between visceral fat and cardiovascular disease. The association between hepatic fat and cardiovascular disease is less clear with discordant results. Novel evidence demonstrates sodium glucose co-transporter-2 (SGLT2) inhibitors facilitate modest weight loss and reductions in ectopic fat depots in patient with type 2 diabetes. Glucagon-like peptide-1 (GLP-1) receptor agonists have been associated with decreased visceral/hepatic fat and reductions in MACE in populations with type 2 diabetes and with overweight/obesity. Clear associations between visceral fat and cardiometabolic outcomes have been established, whereas the impact of hepatic fat remains less clear. Lifestyle modification and pharmacologic interventions remain the initial therapies, while surgical intervention is associated with improved long-term outcomes. Emerging therapies have demonstrated a profound impact on body fat distribution and cardiometabolic risk.

Functionality, muscular strength and cardiorespiratory capacity in the elderly: relationships between functional and physical tests according to sex and age

Introduction: There are several tests that provide information about physical fitness and functionality in older adults. The aims of this study were: (i) to analyze the differences between sex and age in functional, strength and cardiorespiratory tests; and (ii) to study the correlations between functional, strength and cardiorespiratory tests according to sex and age. Methods: A total of 171 older adults (72.09 ± 13.27 kg; 1.59 ± 0.09 m; 72.72 ± 6.05 years) were divided according to sex (men: n = 63; women: n = 108) and age (≥60 <70: n = 65; ≥70 <80: n = 89; ≥80: n = 18). Anthropometry, body composition, upper limb strength (hand grip; HG), lower limb strength (countermovement jump; CMJ), cardiorespiratory capacity (6 min walking test; 6MWT), timed up and go test (TUG) and Short Physical Performance Battery (SPPB) were assessed. Results: Men showed higher values in CMJ height, HG and expired volume (VE) (p < 0.05). There were no significant differences between sexes in TUG and SPPB. Regarding age, there were significant differences in CMJ, VE and peak oxygen uptake (VO2peak), TUG, gait speed, chair and stand test and SPPB total (p < 0.05). The test times were higher in older people. Regarding correlations, the TUG showed significant correlations in all strength and cardiorespiratory tests, regardless of sex and age. The CMJ correlated more significantly with functional tests compared to HG. Discussion: There were sex and age differences in functional, strength, and cardiorespiratory tests. The execution of quick and low-cost tests such as the CMJ and TUG could provide information on overall physical fitness in older adults.

Correlation analysis of anthropometric indices and type 2 diabetes mellitus in residents aged 60 years and older

Background and purpose

In recent years, the incidence of obesity in people aged 60 and over has increased significantly, and abdominal obesity has been recognized as an independent risk factor for diabetes. Aging causes physiologic decline in multiple body systems, leading to changes in obesity indicators such as BMI. At present, the relationship between abdominal obesity markers and Diabetes mellitus (DM) in people aged 60 years and older remains unclear. Therefore, it is necessary to study the correlation between anthropometric indices and diabetes and explore potential predictors.

Methods

The basic demographic information of participants aged 60 and above in Zhongshan City in 2020 was collected. Physical parameters, blood glucose and other biochemical indices were measured comprehensively. Binary logistic regression analysis was used to explore the relationship between abdominal obesity indicators [Waist circumference, Neck Circumference, Waist-to-hip ratio, Chinese Visceral Obesity Index (CVAI), and visceral obesity index] and diabetes mellitus. ROC characteristic curve was used to analyze the predictive ability of abdominal obesity indicators to DM, and the non-restrictive cubic spline graph was used to visualize the screened obesity indicators and diabetes risk.

Results

Among 9,519 participants, the prevalence of diabetes was 15.5%. Compared with low CVAI, High CVAI level was significantly associated with increased prevalence of DM in males and females (all p &lt; 0.05), in males (OR, 2.226; 95%CI: 1.128–4.395), females (OR, 1.645; 95%CI: 1.013–2.669). After adjusting for potential confounding factors, there were gender differences between neck circumference and the prevalence of DM, and above-normal neck circumference in males was significantly associated with increased prevalence of DM (OR, 1.381; 95% CI: 1.091–1.747) (p &lt; 0.05).

Conclusion

Among these anthropometric indices, CVAI is consistent with the features of fat distribution in older individuals and shows superior discriminative power as a potential predictor of DM, compared to traditional anthropometric parameters.

Muscle and visceral fat infiltration: A potential mechanism to explain the worsening of obstructive sleep apnea with age

STUDY OBJECTIVES

Aging is a major risk factor for obstructive sleep apnoea (OSA) and is associated with increased upper airway collapsibility, but the mechanisms are largely unknown. We hypothesized that the increase in OSA severity and upper airway collapsibility with age are partially mediated by upper airway, visceral and muscle fat infiltration.

METHODS

Male subjects underwent full polysomnography, upper airway collapsibility determination (Pcrit) after sleep induction with midazolam, upper airway and abdominal computed tomography. Tongue and abdominal muscle fat infiltration were assessed by the determination of muscle attenuation with computed tomography.

RESULTS

Eighty-four males with a wide range of age (47 ± 13 years, range 22-69 years) and apnea-hypopnea index (AHI) (30 [14-60] events/h, range 1-90 events/h), were studied. Younger and older males were grouped according to the mean age. Despite similar body mass-index (BMI), older subjects had higher AHI, higher Pcrit, larger neck and waist circumference, higher visceral and upper airway fat volumes (P < 0.01) as compared to younger subjects. Age was associated with OSA severity, Pcrit, neck and waist circumference, upper airway fat volume and visceral fat (P < 0.05), but not with BMI. Older subjects had lower tongue and abdominal muscle attenuation as compared to younger subjects (P < 0.001). Age was inversely associated with tongue and abdominal muscle attenuation, indicating muscle fat infiltration.

CONCLUSIONS

The associations between age, upper airway fat volume, visceral and muscle fat infiltration may help to explain the worsening of OSA and increased upper airway collapsibility with aging.

Multicompartment body composition analysis in older adults: a cross-sectional study

BACKGROUND

During aging, changes occur in the proportions of muscle, fat, and bone. Body composition (BC) alterations have a great impact on health, quality of life, and functional capacity. Several equations to predict BC using anthropometric measurements have been developed from a bi-compartmental (2-C) approach that determines only fat mass (FM) and fat-free mass (FFM). However, these models have several limitations, when considering constant density, progressive bone demineralization, and changes in the hydration of the FFM, as typical changes during senescence. Thus, the main purpose of this study was to propose and validate a new multi-compartmental anthropometric model to predict fat, bone, and musculature components in older adults of both sexes.

METHODS

This cross-sectional study included 100 older adults of both sexes. To determine the dependent variables (fat mass [FM], bone mineral content [BMC], and appendicular lean soft tissue [ALST]) whole total and regional dual-energy X-ray absorptiometry (DXA) body scans were performed. Twenty-nine anthropometric measures and sex were appointed as independent variables. Models were developed through multivariate linear regression. Finally, the predicted residual error sum of squares (PRESS) statistic was used to measure the effectiveness of the predicted value for each dependent variable.

RESULTS

An equation was developed to simultaneously predict FM, BMC, and ALST from only four variables: weight, half-arm span (HAS), triceps skinfold (TriSK), and sex. This model showed high coefficients of determination and low estimation errors (FM: R²_adj: 0.83 and SEE: 3.16; BMC: R²_adj: 0.61 and SEE: 0.30; ALST: R²_adj: 0.85 and SEE: 1.65).

CONCLUSION

The equations provide a reliable, practical, and low-cost instrument to monitor changes in body components during the aging process. The internal cross-validation method PRESS presented sufficient reliability in the model as an inexpensive alternative for clinical field use.

Age is the most important factor for change in body mass index and waist circumference in older people in southern Brazil

OBJECTIVES

The aim of this study is to assess the changes in body mass index and waist circumference (WC) and their associations with sociodemographic, behavioral, and health characteristics in non-institutionalized older people in southern Brazil over a period of ≤6 y.

METHODS

This is a prospective study, with interviews conducted in 2014 and in 2019 to 2020. Of the 1451 individuals from Pelotas, Brazil, aged >60 y and interviewed in 2014, 537 were reevaluated in 2019 to 2020. An increase or decrease was defined as a variation of ≥5% in body mass index and WC in the second visit compared with the first. The association with changes in outcomes was assessed according to sociodemographic, behavioral, and health characteristics using multinomial logistic regression.

RESULTS

Approximately 29% of the older participants lost body mass. Regarding WC, there was an increase in 25.6% in the older participants. The older participants ages ≥80 y had greater odds of losing body mass (odds ratio [OR] = 4.73; 95% confidence interval [CI], 2.29-9.76) and of reducing WC (OR = 2.84; 95% CI, 1.59-6.94). Former smokers had, on average, 41% and 64% lower odds of losing and gaining body mass (95% CI, 0.37-0.95 and 95% CI, 0.19-0.68, respectively), and those who were on ≥5 medications had greater odds of gaining body mass (OR = 1.92; 95% CI, 1.12-3.28) and WC (OR = 1.79; 95% CI, 1.18-2.74).

CONCLUSIONS

Despite the high proportion of older people who kept their body mass index and WC stable during this period, many of them lost body mass and gained WC. The findings also highlighted the importance of age in the nutritional changes observed in the population.

Associations between exercise capacity, p16INK4a expression and inflammation among adult survivors of childhood cancer

BACKGROUND

Over 50% of childhood cancer survivors are exercise intolerant, with maximal aerobic capacities comparable to individuals decades older, suggesting early physiologic ageing. In addition, 36% of survivors are obese. Optimal exercise capacity provides a foundation to support daily function and healthy body habitus and is associated with benefits to cognition, cardiovascular health, and longevity. Cellular senescence and inflammation are key mechanisms that drive age-related disease, quantifiable as biomarkers in peripheral blood.

AIMS

This study aimed to evaluate associations between p16INKa, a biomarker of cellular senescence, and inflammation and exercise capacity among adult survivors of childhood cancer.

MATERIALS AND METHODS

Eligible survivors were recruited from the St. Jude Lifetime (SJLIFE) Cohort Study. Exercise capacity was assessed by maximal oxygen uptake (VO2, ml/kg/min) obtained via cardiopulmonary exercise testing using a modified Bruce protocol. Body fat (%) was determined from dual energy x-ray absorptiometry (DEXA). Peripheral blood samples were used to evaluate log2 p16INK4a mRNA expression, a biomarker of cellular senescence, and inflammation with high sensitivity C-reactive protein (hs-CRP) levels. Multivariable regression evaluated associations between p16INK4a, hs-CRP, body fat, and exercise capacity.

RESULTS

Participants included 185 five-year childhood cancer survivors (mean age 36.6 [range 20.1 - 55.7] years, 44% male, 77% non-Hispanic white, 53% leukemia/lymphoma). Compared to males, females had lower peak VO2 (mean ± SD, 22.5 ± 8.2 vs. 28.8 ± 7.7 ml/kg/min, p<0.01), higher p16INK4a expression (9.6 ± 1.2 vs. 9.2 ± 1.2 fold, p=0.02), and hs-CRP concentration (5.9 ± 8.4 vs. 3.3 ± 3.9 mg/L, p=0.01). Among females (n=103), hs-CRP concentration (β -0.2, 95% CI -0.34 to -0.05, p=0.01) and p16INK4a expression (β-5.32, 95% CI 10.42 to -0.22, p=0.04) were inversely associated and statistically significant with peak exercise capacity, with a significant interaction between p16INK4a expression and body fat (β 0.15, 95% CI 0.02 to 0.28, p=0.03). Among males (n=82), p16INK4a expression (β -1.01, 95% CI -2.14 to 0.12, p=0.08), and body fat (β -0.54, 95% CI -0.70 to -0.38, p<0.01) were inversely associated with peak exercise capacity.

CONCLUSION

Inflammation and p16INK4a expression, a biomarker of cellular senescence, are associated with lower exercise capacity in childhood cancer survivors, suggesting potential targets or outcome measures for interventions designed to prevent or remediate accelerated physiologic ageing in this population.

Sex Difference in Cutoff and Prevalence of Sarcopenia among 300,090 Urban Korean Population: Association with Metabolic Syndrome

Background and Objectives: The study aimed to establish the threshold values and prevalence of sarcopenia and to investigate the association of sarcopenia with metabolic syndrome in an urban Korean population. Materials and Methods: The study included 300,090 adults who underwent anthropometric analyses by bioelectrical impedance analyzer. Sarcopenia was defined as: (1) class I, skeletal muscle mass index (SMI) within −1 to −2 standard deviations (SDs); (2) or class II, <−2 SD of SMI in a young population. Results: Low SMI threshold levels for class I and class II sarcopenia were 39.8 and 36.7% in men, and 35.5 and 32.3% in women. Among all age groups, the prevalence rates of sarcopenia were highest in the age group 80−89 years. Following adjustment for possible confounders including age, sex, height, metabolic and health behavioral factors, adjusted odds ratios (95% confidence intervals) for the risk of metabolic syndrome were 2.43 (2.33−2.54) for class I and 2.69 (2.49−2.91) for class II sarcopenia, compared with the normal reference. Sarcopenia was more strongly associated with metabolic syndrome in women than men (p for interaction < 0.01). The threshold values and prevalence of sarcopenia were demonstrated in a large Korean urban population. Conclusions: This study identified that sarcopenia was associated with increased risk of metabolic syndrome, showing itself to be significantly higher in women than men.

Associations of eating speed with fat distribution and body shape vary in different age groups and obesity status

Background

Eating speed has been reported to be associated with energy intake, body weight, waist circumference (WC), and total body fat. However, no study has explored the association between eating speed and body fat distribution, especially its difference among different age or body mass index (BMI) groups.

Methods

4770 participants aged 18–80 years were recruited from the baseline survey of the Lanxi Cohort Study. They were categorized into three groups according to meal duration. Linear regression analyses were performed among all participants and separately by age group and obesity status to evaluate the associations of WC and total and regional fat mass percentages (FM%) with eating speed.

Results

After adjusting for confounding factors, eating slowly was significantly related to lower WC, lower total, trunk, and android FM%, lower android-to-gynoid fat mass ratio, and higher leg and gynoid FM%. After stratification by age or obesity status, the associations were especially prominent among participants aged 18–44 years or those with BMI < 24 kg/m². No significant trends were found for participants aged 65–80 years or those who were overweight/obese.

Conclusions

Eating slowly is closely related with better fat distribution among Chinese adults, especially for those aged 18–44 years and those with BMI < 24 kg/m². If confirmed prospectively, it might be a potential efficient approach to improve fat distribution.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00698-w.

Food consumption, anthropometry and body composition of patients diagnosed with Parkinson’s disease

ABSTRACT Objective The aim of the present study was to evaluate the consumption of risk and protective foods for chronic noncommunicable diseases and to investigate associations with anthropometric parameters and body composition in individuals with Parkinson’s disease. Methods A case-series study was conducted with 79 adult and elderly patients of both genders in outpatient care. Food intake was evaluated using a food frequency questionnaire for the identification of foods with greater daily consumption, stratified by gender. The consumption frequency of each food was converted into scores of two food groups characteristics: risk and protection. The conceptual model took into account sociodemographic, behavioral and anthropometric variables as well as body composition. Results A total of 72.1% of the participants in the sample had excess weight based on the body mass index and 43.5% had excess body fat. The consumption of protective foods was greater among individuals with a higher body mass index and with a greater rate of body fat. Conclusion The data indicate a situation of reverse causality and reveal the complexity of the relationship among food intake, body fat and chronic noncommunicable diseases.

Obesity, Senescence, and Senolytics

Obesity is a major risk factor for the development of comorbidities such as type 2 diabetes, neurodegenerative disorders, osteoarthritis, cancer, cardiovascular and renal diseases. The onset of obesity is linked to an increase of senescent cells within adipose tissue and other organs. Cellular senescence is a stress response that has been shown to be causally linked to aging and development of various age-related diseases such as obesity. The senescence-associated-secretory phenotype of senescent cells creates a chronic inflammatory milieu that leads to local and systemic dysfunction. The elimination of senescent cells using pharmacological approaches (i.e., senolytics) has been shown to delay, prevent, or alleviate obesity-related organ dysfunction.

MECHANISMS IN ENDOCRINOLOGY: Human brown adipose tissue as a therapeutic target: warming up or cooling down?

Excessive accumulation of white adipose tissue leads to obesity and its associated metabolic health consequences such as type 2 diabetes and cardiovascular disease. Several approaches to treat or prevent obesity including public health interventions, surgical weight loss, and pharmacological approaches to reduce caloric intake have failed to substantially modify the increasing prevalence of obesity. The (re-)discovery of active brown adipose tissue (BAT) in adult humans approximately 15 years ago led to a resurgence in research into whether BAT activation could be a novel therapy for the treatment of obesity. Upon cold stimulus, BAT activates and generates heat to maintain body temperature, thus increasing energy expenditure. Activation of BAT may provide a unique opportunity to increase energy expenditure without the need for exercise. However, much of the underlying mechanisms surrounding BAT activation are still being elucidated and the effectiveness of BAT as a therapeutic target has not been realised. Research is ongoing to determine how best to expand BAT mass and activate existing BAT; approaches include cold exposure, pharmacological stimulation using sympathomimetics, browning agents that induce formation of thermogenic beige adipocytes in white adipose depots, and the identification of factors secreted by BAT with therapeutic potential. In this review, we discuss the caloric capacity and other metabolic benefits from BAT activation in humans and the role of metabolic tissues such as skeletal muscle in increasing energy expenditure. We discuss the potential of current approaches and the challenges of BAT activation as a novel strategy to treat obesity and metabolic disorders.

Sarcopenia, obesity, osteoporosis and old age

Modern concepts about body composition in the elderly are described in the review. Particular attention is paid to possible causes and pathogenetic aspects of sarcopenia, as well as modern diagnostic approaches to its recognition. The ageing process is inevitably combined with diverse changes in body composition. This age-related evolution can be described by three main processes: a decrease in the growth and mineral density of bone tissue (osteopenia and osteoporosis); progressive decrease in muscle mass; an increase in adipose tissue (sarcopenia and sarcopenic obesity) with its redistribution towards central and visceral fat accumulation. Sarcopenia and osteoporosis are considered the main geriatric syndromes. These pathological conditions contribute to a significant decrease in the quality of life in the elderly; create conditions for the loss of independence and require long-term care, increase the frequency of hospitalizations and ultimately result in adverse outcomes.

Sex differences in the prevalence of obesity in 800,000 Chinese adults with type 2 diabetes

AIMS

To estimate the sex differences in the prevalence of overweight and obesity aged 20-89 in Chinese patients with type 2 diabetes (T2D).

METHODS

811,264 patients with T2D from six hospital-based, cross-sectional studies, and 46,053 subjects from the general population were included in our analysis. Prevalence of underweight, overweight, obesity were calculated in each sex.

RESULTS

In patients with T2D, the standardized prevalence of underweight (BMI <18.5 kg/m2), overweight (24 kg/m2 ≤ BMI < 28 kg/m2), and general obesity (BMI ≥28 kg/m2) were 2.2%, 43.2%, and 11.6%, respectively. Similar trend patterns of the prevalence of underweight and overweight were observed in general and T2D population, in males and females with T2D (all P for trend <0.01). In patients with T2D, patients at a younger age and older age were more likely to be underweight. The prevalence of overweight increased first, then stabilized or decreased with age. However, different trend patterns of the prevalence of obesity in males and females were found. In males, the prevalence of obesity decreased first, and then stabilized after 60 years of age. In females, the prevalence of obesity decreased first, then increased after 50 years of age. In the general population, the prevalence of obesity increased with age in females, while, the trend of prevalence of obesity with age in males was not obvious.

CONCLUSION

Different trends in the prevalence of obesity with age in different sex were found in Chinese patients with T2D.

Elevated gut microbiome abundance of Christensenellaceae, Porphyromonadaceae and Rikenellaceae is associated with reduced visceral adipose tissue and healthier metabolic profile in Italian elderly

Aging is accompanied by physiological changes affecting body composition and functionality, including accumulation of fat mass at the expense of muscle mass, with effects upon morbidity and quality of life. The gut microbiome has recently emerged as a key environmental modifier of human health that can modulate healthy aging and possibly longevity. However, its associations with adiposity in old age are still poorly understood. Here we profiled the gut microbiota in a well-characterized cohort of 201 Italian elderly subjects from the NU-AGE study, by 16S rRNA amplicon sequencing. We then tested for association with body composition from dual-energy X-ray absorptiometry (DXA), with a focus on visceral and subcutaneous adipose tissue. Dietary patterns, serum metabolome and other health-related parameters were also assessed. This study identified distinct compositional structures of the elderly gut microbiota associated with DXA parameters, diet, metabolic profiles and cardio-metabolic risk factors.

Validation of Dual Energy X-Ray Absorptiometry and Nuclear Magnetic Resonance in the Analysis of Body Composition in Mice

Background

As an instrument for measuring body composition in experimental animals, dual energy X-ray absorptiometry (DXA) is ideal for accuracy, cost, and measurement efficiency. However, there is too little insight into the effectiveness of the various aspects of applying DXA to experimental animals. We investigated whether to compare and verify the precision and accuracy of DXA and nuclear magnetic resonance (NMR) animal body composition analyzers.

Methods

We used 30 Institution of Cancer Research mice in the study. First, in order to evaluate the reproducibility of DXA and NMR, we did repeated measurements by repositioning each mouse in anesthesia and euthanasia states. Subsequently, the accuracy of each device was evaluated by comparing the weight measured before the experiment, the weight of the tissue extracted from the mice after the experiment, and the measured DXA and NMR. In addition, when measuring the body composition of animals, we compared the time and the measurable body composition parameters and summarized the advantages and disadvantages of the 2 devices.

Results

Compared to NMR, DXA had the advantage of a fast measurement of bone composition and rapid image analysis. In addition, DXA showed a higher correlation (>95%) with fat mass, lean mass baseline than did NMR (>85%).

Conclusions

In conclusion, DXA was confirmed to have higher precision and measurement accuracy than did NMR. Therefore, DXA is an effective method for evaluating the body composition of experimental animals.

Ultrasound imaging, a stethoscope for body composition assessment

Dysregulation of the human's energy balance, mediated by non-performing endocrine organs (liver, skeletal muscle and adipose tissue, above all), can be related to human metabolic disorders characterized by an impaired body composition (BC), such as obesity and sarcopenia. While it is possible to monitor the BC and its variations at different levels, the tissue-organ composition studies have been proven to provide the most clinically applicable information. Ultrasonography (US), a fast, non-invasive, low-cost and widely available technique, holds great potential in the study of BC, as it can directly measure muscles, organs, visceral and subcutaneous fat tissue in different sections of the abdomen and body, overcoming some limits of anthropometric evaluation and other imaging techniques. Purpose of this review article is to explore the technical aspects and the applied methods of US examination to assess the potential clinical role of this technique in the context of BC characterization, investigating four pivotal topics [abdominal fat compartments, subcutaneous adipose tissue (SAT), skeletal muscle, liver].

Gender-specific association of body composition with inflammatory and adipose-related markers in healthy elderly Europeans from the NU-AGE study

Objectives

The aim of this work was to examine the cross-sectional relationship between body composition (BC) markers for adipose and lean tissue and bone mass, and a wide range of specific inflammatory and adipose-related markers in healthy elderly Europeans.

Methods

A whole-body dual-energy X-ray absorptiometry (DXA) scan was made in 1121 healthy (65–79 years) women and men from five European countries of the “New dietary strategies addressing the specific needs of elderly population for a healthy aging in Europe” project (NCT01754012) cohort to measure markers of adipose and lean tissue and bone mass. Pro-inflammatory (IL-6, IL-6Rα, TNF-α, TNF-R1, TNF-R2, pentraxin 3, CRP, alpha-1-acid glycoprotein, albumin) and anti-inflammatory (IL-10, TGF-β1) molecules as well as adipose-related markers such as leptin, adiponectin, ghrelin, and resistin were measured by magnetic bead-based multiplex-specific immunoassays and biochemical assays.

Results

BC characteristics were different in elderly women and men, and more favorable BC markers were associated with a better adipose-related inflammatory profile, with the exception of skeletal muscle mass index. No correlation was found with the body composition markers and circulating levels of some standard pro- and anti-inflammatory markers like IL-6, pentraxin 3, IL-10, TGF-β1, TNF-α, IL-6Rα, glycoprotein 130, TNF-α-R1, and TNF-α-R2.

Conclusions

The association between BC and inflammatory and adipose-related biomarkers is crucial in decoding aging and pathophysiological processes, such as sarcopenia. DXA can help in understanding how the measurement of fat and muscle is important, making the way from research to clinical practice.

Key Points

• Body composition markers concordantly associated positively or negatively with adipose-related and inflammatory markers, with the exception of skeletal muscle mass index.

• No correlation was found with the body composition markers and circulating levels of some standard pro- and anti-inflammatory markers like IL-6, pentraxin 3, IL-10, TGF-β1, TNF-α, IL-6Rα, gp130, TNF-α-R1, and TNF-α-R2.

• Skeletal muscle mass index (SMI) shows a good correlation with inflammatory profile in age-related sarcopenia.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5973-2) contains supplementary material, which is available to authorized users.

Aging and Imaging Assessment of Body Composition: From Fat to Facts

The aging process is characterized by the chronic inflammatory status called "inflammaging", which shares major molecular and cellular features with the metabolism-induced inflammation called "metaflammation." Metaflammation is mainly driven by overnutrition and nutrient excess, but other contributing factors are metabolic modifications related to the specific body composition (BC) changes occurring with age. The aging process is indeed characterized by an increase in body total fat mass and a concomitant decrease in lean mass and bone density, that are independent from general and physiological fluctuations in weight and body mass index (BMI). Body adiposity is also re-distributed with age, resulting in a general increase in trunk fat (mainly abdominal fat) and a reduction in appendicular fat (mainly subcutaneous fat). Moreover, the accumulation of fat infiltration in organs such as liver and muscles also increases in elderly, while subcutaneous fat mass tends to decrease. These specific variations in BC are considered risk factors for the major age-related diseases, such as cardiovascular diseases, type 2 diabetes, sarcopenia and osteoporosis, and can predispose to disabilities. Thus, the maintenance of a balance rate of fat, muscle and bone is crucial to preserve metabolic homeostasis and a health status, positively contributing to a successful aging. For this reason, a detailed assessment of BC in elderly is critical and could be an additional preventive personalized strategy for age-related diseases. Despite BMI and other clinical measures, such as waist circumference measurement, waist-hip ratio, underwater weighing and bioelectrical impedance, are widely used as a surrogate measure for body adiposity, they barely reflect the distribution of body fat. Because of the great advantages offered by imaging tools in research and clinics, the attention of clinicians is now moving to powerful imaging techniques such as computed tomography, magnetic resonance imaging, dual-energy X-ray absorptiometry and ultrasound to obtain a more accurate estimation of BC. The aim of this review is to present the state of the art of the imaging techniques that are currently available to measure BC and that can be applied to the study of BC changes in the elderly, outlining advantages and disadvantages of each technique.

A Cross-Sectional Analysis of Body Composition Among Healthy Elderly From the European NU-AGE Study: Sex and Country Specific Features

Body composition (BC) is an emerging important factor for the characterization of metabolic status. The assessment of BC has been studied in various populations and diseases such as obesity, diabetes, endocrine diseases as well as physiological and paraphysiological conditions such as growth and aging processes, and physical training. A gold standard technique for the assessment of human BC at molecular level is represented by dual-energy X-ray absorptiometry (DXA), which is able to precisely assess the body mass (and areal bone mineral density-aBMD) on a regional and whole-body basis. For the first time, within the framework of the NU-AGE project, BC has been assessed by means of a whole-body DXA scan in 1121 sex-balanced free-living, apparently healthy older adults aged 65-79 years enrolled in 5 European countries (Italy, France, United Kingdom, Netherlands, and Poland). The aim of this analysis is to provide a complete profile of BC in healthy elderly participants from five European countries and to investigate country- and sex-related differences by state-of-the-art DXA technology. To compare BC data collected in different centers, specific indexes and ratios have been used. Non-parametric statistical tests showed sex-specific significant differences in certain BC parameters. In particular, women have higher fat mass (FM) (Fat/Lean mass ratio: by 67%, p < 2.2e-16) and lower lean mass (Lean Mass index: by -18%, p < 2.2e-16) than men. On the other hand, men have higher android FM than women (Android/gynoid FM ratio: by 56%, p < 2.2e-16). Interesting differences also emerged among countries. Polish elderly have higher FM (Fat/Lean mass ratio: by 52%, p < 2.2e-16) and lower lean mass (Skeletal Mass index: by -23%, p < 2.2e-16) than elderly from the other four countries. At variance, French elderly show lower FM (Fat/Lean mass ratio: by -34%, p < 2.2e-16) and higher lean mass (Skeletal Mass index: by 18%, p < 2.2e-16). Moreover, five BC profiles in women and six in men have been identified by a cluster analysis based on BC parameters. Finally, these data can serve as reference for normative average and variability of BC in the elderly populations across Europe.

Correlation between DXA and laboratory parameters in normal weight, overweight, and obese patients

OBJECTIVE

The aim of this study was to review the existence and types of correlations between body composition densitometric parameters and laboratory values associated to cardiometabolic risk.

METHODS

We retrospectively analyzed data from 316 individuals in the weight range from normality to super-obesity, submitted to total body dual-energy x-ray absorptiometry (DXA) scans and routine biochemistry at S.Orsola-Malpighi Hospital from June 2010 to March 2014. The study included 182 women, 45.8 ± 13.4 y of age, with a body mass index (BMI) of 31.5 (± 11) kg/m² (group F) and 134 men, 45.4 ± 13.6 y of age, with a BMI of 27.6 (± 7.8) kg/m² (group M). All patients underwent whole-body scan (Lunar iDXA, GE Healthcare, Madison, WI, USA) and laboratory analysis (blood fasting glucose, total cholesterol, high-density lipoprotein cholesterol, tricylglycerides [TGs], aspartate aminotransferase, and alanine aminotransferase). Correlation between laboratory values and total body and regional fat mass (including visceral adipose tissue [VAT] and subcutaneous adipose tissue in the android region), and lean mass parameters were analyzed with linear and stepwise regressions analysis (significance limit, P < 0.05). Receiver operating characteristic curves were performed to assess the accuracy of the best-fit DXA parameter (VAT) to identify at least one laboratory risk factor.

RESULTS

In both groups, BMI and densitometric parameters showed a linear correlation with fasting blood glucose and TG levels and an inverse correlation with high-density lipoprotein cholesterol (P < 0.05), whereas no correlation was observed with total cholesterol levels. The only densitometric parameter retained in the final model of stepwise multiple regression was VAT for fasting blood glucose (group F: β = 0.4627, P < 0.0001; group M: β = 0.6221, P < 0.0001) and TG levels (group F: β = 0.4931, P < 0.0001; group M: β = 0.1990, P < 0.0261) independently of BMI. The optimal cutoff points of VAT to identify the presence of at least one laboratory risk factor were >1395 g and >1479 cm³ for men and >1281 g and >1357 cm³ for women.

CONCLUSIONS

DXA analysis of VAT is associated with selected laboratory parameters used for the evaluation of cardiometabolic risk and could be per se a helpful parameter in the assessment of clinical risk.

Relationship between skeletal muscle mass and lung function in Korean adults without clinically apparent lung disease

Previous studies have demonstrated that low skeletal muscle mass is related to decreased lung function in patients with chronic obstructive pulmonary disease. However, there is little information about the relationship between skeletal muscle mass and lung function in asymptomatic adults without clinically apparent lung disease.This was a cross-sectional study of 240,562 Korean adults without known lung disease. All subjects underwent both pulmonary function test (PFT) and bioelectrical impedance analysis in the health checkup program at Kangbuk Samsung Hospital. Skeletal muscle mass index (SMI) was estimated as skeletal muscle mass/weight×100. We analyzed the relationship between SMI and PFT using multivariate logistic regression models.Of the 240,562 study subjects, values for forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and peak expiratory flow (PEF) were decreased across quartiles (Qs) of decreasing SMI. After adjustments for various confounders including demographic and health behavior-related factors, odds ratios (ORs; 95% confidence interval) for subjects with FVC% <80% for Q1-Q3 compared with Q4 (reference) were 2.97 (2.74-3.17), 2.11 (1.99-2.27), and 1.66 (1.52-1.83), respectively. ORs for subjects with FEV1% <80% for Q1-Q3 compared with Q4 were 2.64 (2.43-2.83), 1.96 (1.83-2.09), and 1.51 (1.43-1.62), respectively. Lastly, OR for subjects with PEF% <80% for Q1-Q3 compared with Q4 were 1.73 (1.58-1.89), 1.35 (1.26-1.45), and 1.23 (1.15-1.30), individually. Subgroup analyses for gender and all age groups showed the associations of decreasing SMI Qs with lower FVC%, FEV1%, and PEF% remained significant.Decreased SMI was independently associated with decline in lung function in apparently healthy adults. This association was sustained in subgroup analyses by gender and all age groups.

Comparison between Dual-Energy X-ray Absorptiometry and Bioelectrical Impedance Analyses for Accuracy in Measuring Whole Body Muscle Mass and Appendicular Skeletal Muscle Mass

We evaluate the accuracy of whole body muscle mass (WBMM) and appendicular skeletal muscle mass (ASMM) assessed by bioelectrical impedance analysis (BIA) using an InBody770 machine (InBody, Seoul, Korea) referenced to dual-energy X-ray absorptiometry (DXA) in 507 people (mean age 63.7 ± 10.8 years, body mass index (BMI) 25.2 ± 3.5 kg/m²). Mean WBMMs measured by BIA and DXA were 49.3 ± 6.6 kg and 46.8 ± 6.5 kg in men and 36.1 ± 4.7 kg and 34.0 ± 4.8 kg in women, respectively. The respective effect sizes and 95% confidence intervals (CIs) for the difference were 2.49 (2.22⁻2.76) for men, and 2.12 (1.91⁻2.33) for women. Mean ASMMs measured by BIA and DXA were 22.1 ± 3.3 kg and 19.9 ± 3.2 kg in men, and 15.3 ± 2.5 kg and 13.5 ± 2.2 kg in women, respectively. The respective effect sizes and 95% CIs for the difference were 2.26 (2.10⁻2.41) for men and 1.75 (1.65⁻1.87) for women. The BIA clearly overestimated WBMM by 2.28 kg and ASMM by 1.97 kg compared with DXA. Using BMI, gender, and fat percentage, we derive equations that improved the residuals to.

Quantitative imaging techniques for the assessment of osteoporosis and sarcopenia

Bone and muscle are two deeply interconnected organs and a strong relationship between them exists in their development and maintenance. The peak of both bone and muscle mass is achieved in early adulthood, followed by a progressive decline after the age of 40. The increase in life expectancy in developed countries resulted in an increase of degenerative diseases affecting the musculoskeletal system. Osteoporosis and sarcopenia represent a major cause of morbidity and mortality in the elderly population and are associated with a significant increase in healthcare costs. Several imaging techniques are currently available for the non-invasive investigation of bone and muscle mass and quality. Conventional radiology, dual energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound often play a complementary role in the study of osteoporosis and sarcopenia, depicting different aspects of the same pathology. This paper presents the different imaging modalities currently used for the investigation of bone and muscle mass and quality in osteoporosis and sarcopenia with special emphasis on the clinical applications and limitations of each technique and with the intent to provide interesting insights into recent advances in the field of conventional imaging, novel high-resolution techniques and fracture risk.

Aging of Brown and Beige/Brite Adipose Tissue

Brown adipose tissue aging and the concomitant loss of thermogenic capacity have been linked to an inability to maintain normal energy homeostasis in late life. Similarly, the ability of white fat to convert into brite/beige adipose tissue declines. This may ultimately exacerbate the progression of age-related metabolic pathologies, such as insulin resistance and obesity. The depletion of all types of brown adipocytes during aging is well-established and has been described in rodent models as well as humans. We here review the available literature on the potential mechanisms leading to cell-autonomous and microenvironment-related aspects of brown adipocyte dysfunction. Among these, cellular senescence, mitochondrial impairment, and deteriorating changes to the local and endocrine microenvironments have been proposed. An important goal of aging research is to develop approaches that may not only extend life expectancy but also prolong health-span. These efforts may also be aimed at maintaining metabolic health throughout life by targeting brown adipocyte function.

Decline and Peripheral Redistribution of Fat Mass in Old Age - A Four-Year Prospective Study in 3018 Older Community-Living Adults

BACKGROUND

It is widely recognized that fat will accumulate with ageing and is more prominent centrally. However, there were studies reported that fat might not gain either centrally or generally with ageing.

METHODS

The baseline, 2-year and 4-year total body fat mas, trunk fat mass and percentage fat mass, were measured by DXA in 3018 community-living Chinese older than 65 years. The respective 4-year trajectories of adiposity were analyzed by repeated measure ANOVA p-for-trend test.

RESULTS

There was a trend of increase in total body fat mass in men and a decreasing trend in women but neither reached statistical significance. However, there was a significant increase in percent fat mass in both genders. Fat mass was relatively stable in the 2 young-old groups but it declined in the oldest group, aged 75 years or above. (men, p=0.017; women, p<0.001). On the contrary, a corresponding rise of percent fat mass was observed, which was steeper in the 2 younger age groups but did not change in the oldest group. For trunk fat mass, there was a statistically significant decreasing trend in women (p < 0.001) but it remained static in men (p = 0.092). The fat mass in upper limbs of both genders did not change but for the lower limbs, there was a statistically significant increase in both men (p < 0.001) and women (p < 0.02).

CONCLUSION

Absolute total body fat mass does not accumulate in old age and in the contrary, in the oldest old group (75 years or above), it declined instead. With ageing, fat will redistribute from the central region to the lower limbs.

Significant relationships between a simple marker of redox balance and lifestyle behaviours; Relevance to the Framingham risk score

Oxidative stress has been closely linked to the progressive cell damage associated with emerging non-communicable disease (NCDs). Early detection of these biochemical abnormalities before irreversible cell damage occurs may therefore be useful in identifying disease risk at an individual level. In order to test this hypothesis, this study assessed the relationship between a simple measure of redox status and lifestyle risk factors for NCDs, and the population-based risk score of Framingham. In a cross-sectional study design, 100 apparently healthy middle-aged males (n = 48) and females (n = 52) were asked to complete a comprehensive lifestyle assessment questionnaire, followed by body fat percentage and blood pressure measurements, and blood collection. The ratio of plasma total antioxidant capacity to hydroperoxide (TAC/HPX) was used as an index of redox balance. One-way ANOVA and multiple linear regression analysis were performed to analyse the association between TAC/HPX, lifestyle components and other plasma biomarkers. The TAC/HPX ratio was higher in males compared to females (t96 = 2.34, P = 0.021). TAC/HPX was also lower in participants with poor sleep quality (t93 = 2.39, P = 0.019), with high sleep apnoea risk (t62.2 = 3.32, P = 0.002), with high caffeine (F(2, 93) = 3.97, P = 0.022) and red meat intake (F(2, 93) = 5.55, P = 0.005). These associations were independent of gender. Furthermore, the TAC/HPX ratio decreased with increasing body fat percentage (F(2, 95) = 4.74, P = 0.011) and depression score (t94 = 2.38, P = 0.019), though these associations were dependent on gender. Importantly, a negative association was observed between TAC/HPX levels and the Framingham risk score in both males (r(45) = -0.39, P = 0.008) and females (r(50) = -0.33, P = 0.019) that was independent of other Framingham risk score components. Findings from this study suggests that a relatively simple measure of redox balance such as the TAC/HPX ratio may be a sensitive indicator of redox stress, and may therefore serve as a useful biomarker for assessing an individual's specific NCD risk linked to unhealthy lifestyle practices.

Impact of Incident Heart Failure on Body Composition Over Time in the Health, Aging, and Body Composition Study Population

BACKGROUND

Prevalence of heart failure (HF) increases significantly with age, coinciding with age-related changes in body composition that are common and consequential. Still, body composition is rarely factored in routine HF care.

METHODS AND RESULTS

The Health, Aging, and Body Composition study is a prospective cohort study of nondisabled adults. Using yearly dual-energy x-ray absorptiometry, body composition was assessed in the Health, Aging, and Body Composition study over 6 years, comparing those who developed incident HF versus those who did not. Among 2815 Health, Aging, and Body Composition participants (48.5% men; 59.6% whites; mean age, 73.6±2.9 years), 111 developed incident HF over the 6-year study period. At entry into the Health, Aging, and Body Composition study, men and women who later developed HF had higher total body mass when compared with those versus those who did not develop HF (men, 80.9±10 versus 78.6±12.9 kg, P=0.05; women, 72.7±15.0 versus 68.2±14.2 kg, P=0.01, respectively). However, after developing HF, loss of total lean body mass was disproportionate; men with HF lost 654.6 versus 391.4 g/y in non-HF participants, P=0.02. Loss of appendicular lean mass was also greater with HF (-419.9 versus -318.2 g/y; P=0.02), even after accounting for total weight change. Among women with HF, loss of total and appendicular lean mass were also greater than in non-HF participants but not to the extent seen among men.

CONCLUSIONS

Incident HF in older adults was associated with disproportionate loss of lean mass, particularly among men. Prognostic implications are significant, with key sex-specific inferences on physical function, frailty, disability, and pharmacodynamics that all merit further investigation.

Upper and lower limbs composition: a comparison between anthropometry and dual-energy X-ray absorptiometry in healthy people

The detection of changes in lean mass (LM) distribution can help to prevent disability. This study assessed the degree of association between anthropometric measurements and dual-energy X-ray absorptiometry (DXA) body composition (BC) parameters of the upper and lower limbs in a healthy general population and collected DXA age- and sex-specific values of BC that can be useful to build a reference standard.

PURPOSE

The primary aim of this study was to investigate the reliability of some widely available anthropometric measurements in the assessment of body composition (BC) at the limbs, especially in terms of muscle mass, in a large sample of healthy subjects of different age bands and sex, using fat mass (FM) and lean mass (LM) parameters derived by dual-energy X-ray absorptiometry (DXA) as the gold standard. The secondary aim was to collect DXA age- and sex-specific values of BC of left and right limbs (upper and lower) in a healthy Italian population to be used as reference standards.

METHODS

Two hundred fifty healthy volunteers were enrolled. Arm circumference (AC) and thigh circumference (ThC) were measured, and total and regional BC parameters were obtained by a whole-body DXA scan (Lunar iDXA, Madison, WI, USA; enCORE™ 2011 software version 13.6).

RESULTS

FM/LM showed only fair correlation with AC and ThC in females (r = 0.649 and 0.532, respectively); in males and in the total population, the correlation was low (r = 0.360 or lower, and p non-statistically significant). AC and ThC were not well representative of arms LM in both genders (females r = 0.452, males r = 0.530) independently of age. In general, men of all age groups showed higher values of LM and lean mass index (LMI) in both total and segmental upper and lower limbs. In males, the maximum LM and LMI were achieved in the fifth decade in both upper and lower limbs and then started to decrease with aging. In females, no significant modification with aging was identified in LM and LMI.

CONCLUSION

According to our results, anthropometry is not well representative of LM of arms in both genders, independently of age; therefore, a densitometric examination should be considered for a correct assessment of BC at limbs.

Development of a Whole-Body Physiologically Based Pharmacokinetic Approach to Assess the Pharmacokinetics of Drugs in Elderly Individuals

Background

Because of the vulnerability and frailty of elderly adults, clinical drug development has traditionally been biased towards young and middle-aged adults. Recent efforts have begun to incorporate data from paediatric investigations. Nevertheless, the elderly often remain underrepresented in clinical trials, even though persons aged 65 years and older receive the majority of drug prescriptions. Consequently, a knowledge gap exists with regard to pharmacokinetic (PK) and pharmacodynamic (PD) responses in elderly subjects, leaving the safety and efficacy of medicines for this population unclear.

Objectives

The goal of this study was to extend a physiologically based pharmacokinetic (PBPK) model for adults to encompass the full course of healthy aging through to the age of 100 years, to support dose selection and improve pharmacotherapy for the elderly age group.

Methods

For parameterization of the PBPK model for healthy aging individuals, the literature was scanned for anthropometric and physiological data, which were consolidated and incorporated into the PBPK software PK-Sim^®. Age-related changes that occur from 65 to 100 years of age were the main focus of this work. For a sound and continuous description of an aging human, data on anatomical and physiological changes ranging from early adulthood to old age were included. The capability of the PBPK approach to predict distribution and elimination of drugs was verified using the test compounds morphine and furosemide, administered intravenously. Both are cleared by a single elimination pathway. PK parameters for the two compounds in younger adults and elderly individuals were obtained from the literature. Matching virtual populations—with regard to age, sex, anthropometric measures and dosage—were generated. Profiles of plasma drug concentrations over time, volume of distribution at steady state (V_ss) values and elimination half-life (t_½) values from the literature were compared with those predicted by PBPK simulations for both younger adults and the elderly.

Results

For most organs, the age-dependent information gathered in the extensive literature analysis was dense. In contrast, with respect to blood flow, the literature study produced only sparse data for several tissues, and in these cases, linear regression was required to capture the entire elderly age range. On the basis of age-informed physiology, the predicted PK profiles described age-associated trends well. The root mean squared prediction error for the prediction of plasma concentrations of furosemide and morphine in the elderly were improved by 32 and 49 %, respectively, by use of age-informed physiology. The majority of the individual V_ss and t_½ values for the two model compounds, furosemide and morphine, were well predicted in the elderly population, except for long furosemide half-lifes.

Conclusion

The results of this study support the feasibility of using a knowledge-driven PBPK aging model that includes the elderly to predict PK alterations throughout the entire course of aging, and thus to optimize drug therapy in elderly individuals. These results indicate that pharmacotherapy and safety-related control of geriatric drug therapy regimens may be greatly facilitated by the information gained from PBPK predictions.

Electronic supplementary material

The online version of this article (doi:10.1007/s40262-016-0422-3) contains supplementary material, which is available to authorized users.

DXA-assessed changes in body composition in obese women following two different weight loss programs

OBJECTIVE

Changes in body composition during weight loss programs might have a significant effect on long-term results. The aim of this study was to test these changes by dual energy x-ray absorptiometry (DXA) in obese women enrolled into two different weight loss medical programs.

METHODS

We prospectively studied 71 women assigned to either an intensive 3-mo cognitive-behavioral therapy (CBT) or a 1-mo nutritional counseling plan (NCP). All patients underwent DXA whole-body scan before treatment and after 3, 6, and 12 mo. Fat mass (FM), non-bone lean mass (LM) and bone mineral content were assessed at whole-body and regional levels. Android visceral adipose tissue (VAT) also was estimated.

RESULTS

Twenty-three patients missed one or more follow-up controls and were excluded from the final analysis. Twenty-seven patients (body mass index [BMI] 41.9 ± 6.7 kg/m²) remained in the CBT group and 21 (BMI 33.4 ± 4 kg/m²) in the NCP group. The progressive decrease of BMI in both groups was associated with reduced whole-body and regional FM, which was more marked in CBT. During follow-up, a progressive decrease of total FM-to-LM and android FM-to-LM ratios were observed both in CBT (Δ12-mo versus baseline -7.8 ± 9.6% and -9.5 ± 12.7%, respectively; P < 0.01) and NCP (Δ12-mo versus baseline -5.9 ± 9.6% and -7 ± 13.4%, respectively; P < 0.05). VAT was the parameter showing the largest decrease (-14.2 ± 17.4% and -11.3 ± 18.2% at 12 mo, respectively in CBT and NCP; P < 0.05).

CONCLUSIONS

Lifestyle-induced weight loss is associated with selective changes in body composition parameters, regardless of initial BMI and treatment program, limiting sarcopenic obesity. DXA may quantify the metabolically healthier redistribution of total and regional FM and VAT.

Similarities and interactions between the ageing process and high chronic intake of added sugars

In our societies, the proportions of elderly people and of obese individuals are increasing. Both factors are associated with high health-related costs. During obesity, many authors suggest that it is a high chronic intake of added sugars (HCIAS) that triggers the shift towards pathology. However, the majority of studies were performed in young subjects and only a few were interested in the interaction with the ageing process. Our purpose was to discuss the metabolic effects of HCIAS, compare with the effects of ageing, and evaluate how deleterious the combined action of HCIAS and ageing could be. This effect of HCIAS seems mediated by fructose, targeting the liver first, which may lead to all subsequent metabolic alterations. The first basic alterations induced by fructose are increased oxidative stress, protein glycation, inflammation, dyslipidaemia and insulin resistance. These alterations are also present during the ageing process, and are closely related to each other, one leading to the other. These basic alterations are also involved in more complex syndromes, which are also favoured by HCIAS, and present during ageing. These include non-alcoholic fatty liver disease, hypertension, neurodegenerative diseases, sarcopenia and osteoporosis. Cumulative effects of ageing and HCIAS have been seldom tested and may not always be strictly additive. Data also suggest that some of the metabolic alterations that are more prevalent during ageing could be related more with nutritional habits than to intrinsic ageing. In conclusion, it is clear that HCIAS interacts with the ageing process, accelerates the accumulation of metabolic alterations, and that it should be avoided.

Conserved and species-specific molecular denominators in mammalian skeletal muscle aging

Aging is a complex phenomenon involving functional decline in multiple physiological systems. We undertook a comparative analysis of skeletal muscle from four different species, i.e. mice, rats, rhesus monkeys, and humans, at three different representative stages during their lifespan (young, middle, and old) to identify pathways that modulate function and healthspan. Gene expression profiling and computational analysis revealed that pathway complexity increases from mice to humans, and as mammals age, there is predominantly an upregulation of pathways in all species. Two downregulated pathways, the electron transport chain and oxidative phosphorylation, were common among all four species in response to aging. Quantitative PCR, biochemical analysis, mitochondrial DNA measurements, and electron microscopy revealed a conserved age-dependent decrease in mitochondrial content, and a reduction in oxidative phosphorylation complexes in monkeys and humans. Western blot analysis of key proteins in mitochondrial biogenesis discovered that (i) an imbalance toward mitochondrial fusion occurs in aged skeletal muscle and (ii) mitophagy is not overtly affected, presumably leading to the observed accumulation of abnormally large, damaged mitochondria with age. Select transcript expression analysis uncovered that the skeletal inflammatory profile differentially increases with age, but is most pronounced in humans, while increased oxidative stress (as assessed by protein carbonyl adducts and 4-hydroxynonenal) is common among all species. Expression studies also found that there is unique dysregulation of the nutrient sensing pathways among the different species with age. The identification of conserved pathways indicates common molecular mechanisms intrinsic to health and lifespan, whereas the recognition of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.

Aging is a complex phenomenon involving functional declines in multiple physiological systems with the passage of time. Focusing on skeletal muscle, a group of international scientists identified pathways involved in healthspan and by determining global gene expression profiles across species they exposed common mechanisms fundamental to the aging process. Their experimental design involved comparative analysis of mice, rats, rhesus monkeys and humans, targeting three key time points during their respective lifespans. Pathways related to oxidative stress, inflammation and nutrient signaling, which function collectively to affect the quality and status of mitochondria, emerged across all species in an age-influenced manner. The identification of conserved pathways reveals molecular mechanisms intrinsic to health and survival, whereas the unveiling of species-specific pathways emphasizes the importance of human studies for devising optimal therapeutic modalities to slow the aging process.

The role of DXA in sarcopenia

Sarcopenia is a condition characterized by progressive and generalized reduction in skeletal muscle mass and muscle strength, associated with an increased risk of adverse outcomes (disability, hospitalization, death). The growing attention in the last years, aiming to establish a consensus definition and treatment, reflects the interest of the scientific community toward this complex condition, which has many implications in clinical practice and public health. Dual-energy X-ray absorptiometry (DXA) is the gold-standard technique in the analysis of body composition at molecular level, providing assessment and quantification of fat mass, lean mass and bone mineral content, both in a single body region of interest and at whole-body level. In particular, through the assessment of non-bone lean mass parameters, such as appendicular lean mass adjusted for BMI or height (ALM/BMI and ALM/ht², respectively), it is possible to discriminate subjects with "physiological" loss of muscle mass from those with "pathological" impoverishment of this compartment, referring to specific cutoff values validated in the literature, but keeping in mind the lack of standardization of DXA measures. In addition, it is useful in treatment planning, estimating resting energy expenditure, and in follow-up, because it allows quantifying with high reproducibility the modifications in BC, distinguishing when the change is biological (deterioration due to a progression of the disease or improvement due to treatment). Due to DXA favorability in terms of accuracy, simplicity, availability, low cost and low radiation exposure, its role in sarcopenia diagnosis is becoming increasingly important, emerging as reference assessment technique in muscle mass evaluation.

DXA: Technical aspects and application

The key role of dual-energy X-ray absorptiometry (DXA) in the management of metabolic bone diseases is well known. The role of DXA in the study of body composition and in the clinical evaluation of disorders which directly or indirectly involve the whole metabolism as they may induce changes in body mass and fat percentage is less known or less understood. DXA has a range of clinical applications in this field, from assessing associations between adipose or lean mass and the risk of disease to understanding and measuring the effects of pathophysiological processes or therapeutic interventions, in both adult and paediatric human populations as well as in pre-clinical settings. DXA analyses body composition at the molecular level that is basically translated into a clinical model made up of fat mass, non-bone lean mass, and bone mineral content. DXA allows total and regional assessment of the three above-mentioned compartments, usually by a whole-body scan. Since body composition is a hot topic today, manufacturers have steered the development of DXA technology and methodology towards this. New DXA machines have been designed to accommodate heavier and larger patients and to scan wider areas. New strategies, such as half-body assessment, permit accurate body scan and analysis of individuals exceeding scan field limits. Although DXA is a projective imaging technique, new solutions have recently allowed the differential estimate of subcutaneous and intra-abdominal visceral fat. The transition to narrow fan-beam densitometers has led to faster scan times and better resolution; however, inter- or intra-device variation exists depending on several factors. The purposes of this review are: (1) to appreciate the role of DXA in the study of body composition; (2) to understand potential limitations and pitfalls of DXA in the analysis of body composition; (3) to learn about technical elements and methods, and to become familiar with biomarkers in DXA.

Visceral fat and body composition changes in a female population after RYGBP: a two-year follow-up by DXA

BACKGROUND

Our aim was to monitor the impact of Roux-en-Y gastric bypass (RYGBP) on body composition over a 24-month period by dual-energy X-ray absorptiometry (DXA).

METHODS

Forty-one women (40.6 ± 10.0 years old; 42.6 ± 6.6 kg/m(2)) entering a bariatric surgery programme were submitted to whole-body DXA (Lunar iDXA) before treatment and after 3, 6, 12 and 24 months. Fat mass (FM), non-bone lean mass (LM), bone mineral content (BMC) and density (BMD) were measured at whole body and regionally. Android visceral adipose tissue (VAT) was estimated by a recently validated software.

RESULTS

Twenty-nine patients (44.3 ± 11.8 years old; BMI, 45.4 ± 8.9 kg/m(2)) concluded the study. Following surgery, the progressive decrease of BMI was associated with reduced whole-body and regional FM. LM showed a moderate decrease at 3 months and stabilized thereafter. A progressive decrease of total FM/LM and android FM/LM ratios were observed in the 3- to 6-month (-19.1 ± 8.4 % and -26.5 ± 10.9 %, respectively; p < 0.0001) and 6- to 12-month periods (-23.5 ± 16.8 % and -29.4 ± 23.9 %, respectively; p < 0.0001). VAT was the parameter showing the largest decrease (-65.6 ± 17.5 % at 12 months; p < 0.0001). Two years after the surgery, a slight but significant decrease of total and regional LM was observed, without any significant change in BMI.

CONCLUSIONS

Body composition significantly changes after RYGBP with a metabolically healthier redistribution of total and regional FM and a positive balance of FM/LM variation. DXA should be considered as a valid supplementary tool for the clinical assessment and follow-up in patients undergoing bariatric surgery.

Trabecular bone score in healthy ageing

OBJECTIVE

The main aim of this work was to report on trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) of healthy Italian subjects to be used as a reference standard for future study in clinical and research settings. The secondary aim was to investigate the link between TBS and conventional parameters of bone and body composition by DXA.

METHODS

250 individuals of 5 age bands (spanning from 18 to 70 years of age, equally distributed for both age and sex) were prospectively recruited. A lumbar spine (LS) DXA scan (Lunar iDXA™; GE Healthcare, Madison, WI) was acquired for each subject and then analysed with the latest version of TBS iNsight v. 2.1 (Med-Imaps, Pessac, France) software. LS bone mineral density (LS BMD), Z-score, T-score and TBS values were collected. Pearson's test was used to investigate the correlations between TBS and LS BMD and the influence of age, body mass index (BMI) and body composition on these parameters.

RESULTS

A significant decrease of TBS and LS BMD was observed with ageing in both males (TBS mean values from 1.486 to 1.374; LS BMD mean values from 1.219 to 1.187) and females (TBS mean values from 1.464 to 1.306; LS BMD mean values from 1.154 to 1.116). No statistically significant difference was achieved among males and females of the same age group for both TBS and LS BMD, with the exception of the fifth age group. A significant correlation was found between LS BMD and TBS values in both sexes (r  = 0.555-0.655, p < 0.0001). BMI influenced LS BMD but not TBS. TBS values were inversely correlated with some fat mass parameters, in particular with visceral adipose tissue (in males: r = -0.332, p < 0.001; in females: r = -0.348, p < 0.0001). No significant correlation was found between TBS and total lean mass, opposite to LS BMD (in males: r = 0.418; p < 0.0001; in females: r = -0.235; p < 0.001).

CONCLUSION

This report is an attempt to start building a database for healthy Italian people providing age- and sex-specific reference curves for TBS. This could help clinicians to improve patient management in the detection of impaired bone mineral status and to monitor bone changes.

ADVANCES IN KNOWLEDGE

The study reports TBS values of a selectively enrolled Italian healthy population, ranging from younger to older ages and including males as a reference standard. Moreover, links between body composition and TBS are explored.

Metabolic equivalents of task are confounded by adiposity, which disturbs objective measurement of physical activity

Physical activity refers any bodily movements produced by skeletal muscles that expends energy. Hence the amount and the intensity of physical activity can be assessed by energy expenditure. Metabolic equivalents of task (MET) are multiplies of the resting metabolism reflecting metabolic rate during exercise. The standard MET is defined as 3.5 ml/min/kg. However, the expression of energy expenditure by body weight to normalize the size differences between subjects causes analytical hazards: scaling by body weight does not have a physiological, mathematical, or physical rationale. This review demonstrates by examples that false methodology may cause paradoxical observations if physical activity would be assessed by body weight scaled values such as standard METs. While standard METs are confounded by adiposity, lean mass proportional measures of energy expenditure would enable a more truthful choice to assess physical activity. While physical activity as a behavior and cardiorespiratory fitness or adiposity as a state represents major determinants of public health, specific measurements of health determinants must be understood to enable a truthful evaluation of the interactions and their independent role as a health predictor.

Genetically determined prospect to become long-lived is associated with less abdominal fat and in particular less abdominal visceral fat in men

PURPOSE

familial longevity is marked by an exceptionally healthy metabolic profile and low prevalence of cardiometabolic disease observed already at middle age. We aim to investigate whether regional body fat distribution, which has previously shown to be associated with cardiometabolic risk, is different in offspring of long-lived siblings compared with controls.

METHODS

our institutional review board approved the study, and all participants (n = 344, average age in years 65.6) gave written informed consent. Offspring (n = 175) of non-agenarian siblings were included. Their partners (n = 169) were enrolled as controls. For abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) measurements, a single-slice 8.0 mm computed tomography (CT) acquisition was planned at the level of the 5th lumbar vertebra. In addition, participants underwent prospectively electrocardiography-triggered unenhanced volumetric CT of the heart. Abdominal VAT and SAT areas (cm(2)) and epicardial adipose tissue (EAT) volumes (ml) were acquired by semi-automated segmentation techniques. Linear regression analysis was performed adjusting for cardiovascular risk factors.

RESULTS

total abdominal fat areas were smaller in male offspring compared with controls (353.0 versus 382.9 cm(2), P = 0.022). The association between low abdominal VAT areas in male offspring (149.7 versus 167.0 cm(2) in controls, P = 0.043) attenuated after additional adjustment for diabetes (P = 0.078). Differences were not observed for females. EAT volumes were similar between offspring of long-lived siblings and controls.

CONCLUSION

males who have genetically determined prospect to become long-lived have less abdominal fat and in particular less abdominal VAT compared with controls.

Epicardial fat accumulation, cardiometabolic profile and cardiovascular events in patients with stages 3-5 chronic kidney disease

BACKGROUND

It has been hypothesized that epicardial adipose tissue (EAT) exerts pathogenic effects on cardiac structures. We analysed the associations between EAT and both cardiovascular (CV) disease risk factors and CV events in patients with chronic kidney disease (CKD).

PATIENTS AND METHODS

We included 277 nondialysed patients [median age 61, interquartile range (IQR) 53-68 years; 63% men] with stages 3-5 CKD in this cross-sectional evaluation. EAT and abdominal visceral adipose tissue (VAT) were assessed by computed tomography. Patients were followed for median 32 (IQR 20-39) months, and the composite of fatal and nonfatal CV events was recorded.

RESULTS

With increasing EAT quartiles, patients were older, had higher glomerular filtration rate, body mass index, waist, VAT and coronary calcification, higher levels of haemoglobin, triglycerides, albumin, C-reactive protein and leptin and higher prevalence of left ventricular hypertrophy and myocardial ischaemia; total and high-density lipoprotein cholesterol, 25-hydroxy-vitamin D and 1, 25-dihydroxy-vitamin D progressively decreased. Associations between EAT and cardiac alterations were not independent of VAT. During follow-up, 58 CV events occurred. A 1-SD higher EAT volume was associated with an increased risk of CV events in crude [hazard ratio (HR) 1.41, 95% confidence interval (CI) (1.12-1.78) and adjusted (HR 1.55, 95% CI 1.21-1.99) Cox models. However, adding EAT to a standard CV disease risk prediction model did not result in a clinically relevant improvement in prediction.

CONCLUSION

Epicardial adipose tissue accumulation in patients with CKD increases the risk of CV events independent of general adiposity. This is consistent with the notion of a local pathogenic effect of EAT on the heart or heart vessels, or both. However, EAT adds negligible explanatory power to standard CV disease risk factors.

Estimate of body composition by Hume's equation: validation with DXA

We investigated how the Hume's equation, using the antipyrine space, could perform in estimating fat mass (FM) and lean body mass (LBM). In 100 (40 male ad 60 female) subjects, we estimated FM and LBM by the equation and compared these values with those measured by a last generation DXA device. The correlation coefficients between measured and estimated FM were r = 0.940 (p < 0.0001) and between measured and estimated LBM were r = 0.913 (p < 0.0001). The Bland-Altman plots demonstrated a fair agreement between estimated and measured FM and LBM, though the equation underestimated FM and overestimated LBM in respect to DXA. The mean difference for FM was 1.40 kg (limits of agreement of -6.54 and 8.37 kg). For LBM, the mean difference in respect to DXA was 1.36 kg (limits of agreement -8.26 and 6.52 kg). The root mean square error was 3.61 kg for FM and 3.56 kg for LBM. Our results show that in clinically stable subjects the Hume's equation could reliably assess body composition, and the estimated FM and LBM approached those measured by a modern DXA device.

White Adipose Tissue Depot-Specific Activity of Lipogenic Enzymes in Response to Fasting and Refeeding in Young and Old Rats

BACKGROUND

Although the heterogeneity of white adipose tissue (WAT) in different anatomical sites is a well-known phenomenon, there are scarce data on aging-associated metabolic alterations in various WAT depots.

OBJECTIVE

We used the model of fasting and refeeding to analyze the effect of aging on the activity of key lipogenic enzymes in retroperitoneal (rWAT), epididymal (eWAT), and subcutaneous (sWAT) adipose tissue depots.

METHODS

5- and 24-month-old male Wistar rats were fasted for 48 h or were fasted for 2 days and subsequently refed for 2 or 4 days. Control animals had ad libitum access to chow. Samples obtained from three WAT deposits were analyzed for the enzymatic activities of ATP citrate lyase (ACL), fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PD). Concentrations of lipids and proteins were measured in the blood serum.

RESULTS

Fasting for 2 days decreased the concentration of free fatty acids only in the young rats. The basal activities of ACL and FAS were lower in eWAT than in rWAT and sWAT of the young rats. In the young rats, fasting did not change ACL and FAS activities in any of the studied depots. Refeeding increased these activities more quickly in rWAT than in eWAT, while in sWAT no induction was observed. ACL and FAS activities were manifold lower in all WAT depots of the old than in those of the young rats. In the old animals fasting had no effect on ACL activity in any depot and decreased FAS activity only in sWAT. After 4 days of refeeding, FAS activity increased in rWAT and sWAT, but no change in ACL activity occurred. G6PD activity in the young rats was lower by 40% in eWAT than in rWAT. The induction of the enzyme by refeeding occurred faster in rWAT than in eWAT, while in sWAT no change in G6PD activity was observed. G6PD activity did not change with aging. Fasting of the old rats decreased G6PD activity in rWAT and sWAT. Refeeding failed to induce the enzyme in these depots, whereas in eWAT G6PD activity increased by 76% after 4 days of refeeding.

CONCLUSION

Fasting and refeeding revealed WAT depot-specific, age-related changes of the activities of lipogenic enzymes.

PEGylated CsxWO3 nanorods as an efficient and stable 915 nm-laser-driven photothermal agent against cancer cells

PEGylated Cs_xWO₃ nanorods were prepared, and they exhibited excellent photothermal performance and high stability for the ablation of cancer cells in vivo.

Abdominal adiposity by ultrasonography: a "pocket" database for reference standard in Italian people

AIMS

To provide a reference standard database of ultrasonographic parameters of abdominal adiposity in healthy people.

METHODS

Italian non-obese volunteers among blood donors were enrolled in 5 age bands (from 18 to 70 year-old) to reach the threshold of 25 males and 25 females per single band (total: 250). All subjects were measured for weight, height and waist circumference and underwent ultrasonography (US) by an expert radiologist for the assessment of several abdominal fat thicknesses (minimum and maximum subcutaneous fat thickness, maximum preperitoneal fat thickness, intrabdominal fat thickness, aorto-mesenteric thickness, and mesenteric fat thickness). In addition, US data were normalized per waist circumference.

RESULTS

From 30s to 50s no statistically significant differences were achieved between males and females for the adiposity markers of visceral fat, while a relevant divergence was proved from 60s to 70s. During ageing a marked increase of the visceral fat compartment was observed in males, while only the preperitoneal circumference was significantly modified in females.

CONCLUSIONS

This paper reports on US parameters of abdominal adiposity of healthy Italian adults, to be used as a reference for daily clinical practice. Data could be also considered as control group for future investigations on physiology, pathological conditions, and differences between countries.

The associations between cardiometabolic risk factors and visceral fat measured by a new dual-energy X-ray absorptiometry-derived method in lean healthy Caucasian women

Excess visceral adipose tissue (VAT) is associated with a cluster of metabolic abnormalities. A new dual-energy X-ray absorptiometry (DXA)-based VAT measurement approach, CoreScan™, computes VAT mass and volume within the android region of a total body DXA scan. However, there have been no reference values developed for this method. The objective of this study was to determine the normal reference ranges for DXA-derived VAT in young, healthy, premenopausal women. We also sought associations between VAT, blood lipids, glucose, insulin and insulin resistance. In 120 randomly selected, normal weight, Caucasian women aged 20-40 years, we measured body fat (BF), VAT and lean mass by DXA. We also assessed blood pressure, waist and hip circumference, waist-to-hip ratio, body mass index, fasting glucose, insulin, triglycerides (TG), and high- (HDL) and low-density lipoproteins. Insulin resistance was evaluated by the homeostasis model assessment (HOMA). VAT mass accounted for 0.37 ± 0.3 % of weight and 1.11 ± 0.72 % of BF. Mean VAT mass and volume were 235.9 ± 183 g (95 % CI 202.7-269.1) and 250.3 ± 194.5 cm(3) (95 % CI 215.1-285.4), respectively. Anthropometric indices moderately correlated with VAT. VAT significantly correlated with HDL (R = -0.193; P = 0.03), glucose (R = 0.252; P = 0.005) and HOMA (R = 0.184; P = 0.049). In this study, we provide normal values of VAT mass and volume measured by DXA and determined for healthy, normal weight, Caucasian women aged 20-40 years. Even in such strictly selected population VAT correlated positively with insulin resistance and inversely with HDL.

Age-related different relationships between ectopic adipose tissues and measures of central obesity in sedentary subjects

Accumulation of fat at ectopic sites has been gaining attention as pivotal contributor of insulin resistance, metabolic syndrome and related cardiovascular complications. Intermuscular adipose tissue (IMAT), located between skeletal muscle bundles and beneath muscle fascia, has been linked to physical inactivity, ageing and body mass index, but little is known about its relationship with the other AT compartments, in particular with increasing age. To address this issue, erector spinae IMAT, epicardial (EAT), intraabdominal (IAAT) and abdominal subcutaneous adipose tissue (SAT) were simultaneously measured by Magnetic Resonance Imaging (MRI) and related to waist circumference measurements and age in 32 sedentary subjects without cardiovascular disease (18 men; 14 women; mean age 48.5±14 years). Fasting glucose, triglycerides and HDL-cholesterol were also assessed. We observed that, after dividing individuals according to age (≤ or >50 years), IMAT and EAT depots were significantly more expanded in older subjects (63.2±8.3 years) than in the younger ones (38.4±5.2 years) (p<0.001). Overall, both IMAT and EAT showed stronger positive associations with increasing age (β = 0.63 and 0.67, respectively, p<0.001 for both) than with waist circumference (β = 0.55 and 0.49, respectively, p<0.01 for both) after adjusting for gender. In addition, the gender-adjusted associations of IMAT and EAT with waist circumference and IAAT were significant in individuals ≤50 years only (p<0.05 for all) and not in the older ones. In contrast, no age-related differences were seen in the relationships of IAAT and SAT with waist circumference. Finally, serum triglycerides levels turned out not to be independently related with ectopic IMAT and EAT. In conclusion, the expansion of IMAT and EAT in sedentary subjects is more strongly related to age than waist circumference, and a positive association of these ectopic depots with waist circumference and IAAT amount can be postulated in younger individuals only.

A 360-degree overview of body composition in healthy people: relationships among anthropometry, ultrasonography, and dual-energy x-ray absorptiometry

OBJECTIVE

The aim of this study was to test the relationship between anthropometry, ultrasonography, and dual-energy x-ray absorptiometry (DXA) for the assessment of body composition in clinical practice.

METHODS

The study was carried out in Italian blood donor volunteers belonging to five different age groups (18-70 y old; 25 men and 25 women per group; N = 250 participants; n = 125 men, n = 125 women). A complete history was collected and routine blood analyses were performed to confirm healthy status. All participants were submitted to whole-body DXA (tricompartmental analysis, regional, and total body), ultrasonography (abdominal adiposity evaluation), and anthropometric measurements. DXA was used as gold standard and its biomarkers were taken as reference for fat-lean mass balance, central-peripheral fat distribution, central or visceral fat, and subcutaneous fat.

RESULTS

Anthropometric and ultrasound parameters were closely associated with most of DXA parameters. Composite markers representative of central and abdominal visceral fat compartments were significantly correlated with waist circumference, waist-to-hip ratio, and intra-abdominal fat thickness by ultrasound, in both men and women (P < 0.025). As expected, subcutaneous depots were significantly correlated with maximum subcutaneous fat thickness measured by ultrasonography (P < 0.025).

CONCLUSIONS

Both anthropometry and ultrasonography provide a reliable estimate of visceral adipose tissue in a non-obese population compared with DXA, whereas anthropometry prediction of subcutaneous adiposity is weak. Physicians should be aware of the limits of these techniques for the assessment of body composition.