An evaluation of patterns of change in total and regional body fat mass in healthy Spanish subjects using dual-energy X-ray absorptiometry (DXA)

Sex Differences in Upper- and Lower-Limb Muscle Strength in Children and Adolescents: A Meta-Analysis

On average, adult men are physically stronger than adult women. The magnitude of this difference depends on the muscle tested, with larger sex differences observed in upper- than lower-limb muscles. Whether body region-specific sex differences in strength exist in children is unclear. The purpose of the current meta-analysis was to determine whether sex differences in muscle strength in children and adolescents differ between upper- and lower-limb muscles. Data were extracted from studies of participants aged ≤ 17 years who completed tests of maximal isometric or isokinetic strength of upper-limb muscles (e.g., elbow flexors and elbow extensors) or lower-limb muscles (e.g., knee extensors and ankle dorsiflexors). Participants were partitioned into three age groups: 5-10 years old, 11-13 years old, and 14-17 years old. The analysis included 299 effects from 34 studies. The total sample was 6634 (3497 boys and 3137 girls). Effect sizes of sex differences in upper- and lower-limb strength were g = 0.65 (95% confidence intervals (CI) [0.46, 0.84]) and 0.34 (95% CI [0.19, 0.50]) in 5-10-year-olds; g = 0.73 (95% CI [0.56, 0.91]) and 0.43 (95% CI [0.27, 0.59]) in 11-13-year olds; and g = 1.84 (95% CI [1.64, 2.03]) and 1.18 (95% CI [1.00, 1.37]) in 14-17-year-olds. Upper- and lower-limb strength were 17% and 8% greater in boys than girls when 5-10 years old, 18% and 10% greater when 11-13 years old, and 50% and 30% greater when 14-17 years old. Thus, boys are stronger than girls on average. This sex difference exists before puberty, increases markedly with male puberty, and is more pronounced in upper- than lower-limb muscles throughout development.

Age-related variations in trunk composition and patterns of regional bone and soft tissue changes in adult Caucasian women by DXA

We explored the regional variations in body composition with advancing age in healthy Caucasian females living in the Mediterranean area. The objectives of this study were to establish body composition values for the trunk in healthy women of a Greek origin and to evaluate the effects of aging on the distribution of truncal bone mass, fat mass (FM) and lean mass (LM). Body composition of the trunk and detailed analysis of its anatomical components-the ribs, the thoracic spine, the lumbar spine and the pelvis, and FM and LM ratios--were calculated in 330 women aged 20-85 years, using DXA. Peak bone mineral density (BMD) of the trunk was attained between ages 30 and 33. The overall truncal BMD reduction with age was 20.7% (p < 0.001). Peak %LM of the trunk was achieved at age 20. The overall reduction of %LM with age for the trunk was 9.8% (p < 0.001). Peak %FM of the trunk was attained between ages 68 and 73, and the overall %FM reduction with age was 2.8% (p > 0.05). Multiple comparative analyses showed that the 51-60 years age group was the landmark age for significant changes of truncal bone mass measures across all age groups (p = 0). For truncal LM and FM metrics, multigroup comparative analysis showed the turning point of significant changes in soft tissue was the 41-50 age bracket (p = 0 and p = 0, respectively). In Greek women, truncal %LM exceeded by far %FM across all ages (p = 0). Our results suggest that aging affects body composition of the trunk in ambulatory healthy women of a Greek origin differently, leading to menopausal loss of bone mass, senior adulthood loss of lean mass, and middle-age storage of fat mass. In adult women, these age-related associations between bone and soft tissue metrics on DXA exams carry implications for the attainment of optimal peak values and shifts in body composition overtime, impacting lifelong skeletal health.

Adiposity Is Related to Inflammatory Disease Activity in Juvenile Idiopathic Arthritis

OBJECTIVE

To identify factors associated with the higher proportion of fatty tissue and overweight/obesity observed in patients with juvenile idiopathic arthritis (JIA).

PATIENTS AND METHODS

We performed a cross-sectional study of 80 JIA patients aged 4-15 years with 80 age- and sex-matched healthy controls. Body composition was assessed using dual-energy x-ray absorptiometry. The 27-joint Juvenile Arthritis Disease Activity score (JADAS27) was calculated. Two multivariate models were constructed to identify factors associated with overweight/obesity and fat mass index (FMI).

RESULTS

No differences were found between cases and controls in body mass index (BMI) or body composition. However, compared with controls, patients with a high inflammatory activity (JADAS27 > 4.2 for oligoarticular JIA or >8.5 for polyarticular disease) had higher values for BMI (p = 0.006); total fat mass (p = 0.003); FMI (p = 0.001); and fat in the legs (p = 0.001), trunk (p = 0.001), and arms (p = 0.002). The factors associated with overweight/obesity in patients were the duration of therapy with biological drugs, measured in months (OR [95% CI] = 1.12 [1.02-1.04]; p = 0.037), and physical activity (OR [95% CI] = 0.214 [0.07-0.68]; p = 0.010), while the factors associated with FMI were age (β [95% CI] = 0.30 [0.17-1.41]; p = 0.014), JADAS27 (β [95% CI] = 0.45 [0.16-1.08]; p = 0.009), and physical activity (β [95% CI] = -0.22 [-5.76 to 0.29]; p = 0.031).

CONCLUSION

Our study revealed no differences between JIA patients with well-controlled disease and low disability and the healthy population in BMI or body composition. Furthermore, the association observed between inflammatory activity and adiposity could be responsible for poorer clinical course.

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.

Assessment of Age-Induced Changes in Body Fat Percentage and BMI Aided by Bayesian Modelling: A Cross-Sectional Cohort Study in Middle-Aged and Older Adults

Background

Loss of fat-free mass (FFM) and gain in body fat (BF) are the key disability risk factors, also instrumental in perpetuating already existing functional disorders. Obesity construed in terms of body mass index (BMI) values, in view of undesirable gain in BF, is a risk factor for cardio-metabolic disorders. Both detrimental processes clearly evidence a scope of involutionary changes characteristic of an aging population, also standing for one of its greatest burdens.

Purpose

The present study aimed to assess the changes in body composition (BC), in conjunction with the relationship between BF% and BMI, for defining overweight and obesity status in middle-aged and older adults, against the select indicator variables under study.

Materials and Methods

The study involved 4799 individuals (33.7% men), PONS Project participants, aged 43-64 years. BF% was measured with the aid of bioelectrical impedance analysis (BIA) method. Age-induced changes in BC were determined against BF%, fat mass (FM), FFM, BMI, fat mass index (FMI), and fat-free mass index (FFMI). The relationship between BF% and BMI was established with the aid of Bayesian regression models, adjusted for gender and age.

Results

In both genders, BF% increased with age at a similar annual rate. The reduction of FFM was noted mainly in men, which in conjunction with BF% gain ensured BMI stability. The increase in BF% in women with stable FFM affected an increase in BMI. Regardless of the BMI threshold, the anticipated (predicted) BF% increased with age in both genders.

Conclusion

Monitoring of BC is of particular importance in older adults, in view of appreciably better characteristics of both the short- and long-term health predictors, as well as overall potential for developing specifically targeted, effective health interventions.

Body fat percentage assessment by skinfold equation, bioimpedance and densitometry in older adults

Background

Body fat estimation allows measuring changes over time attributed to interventions and treatments in different settings such as hospitals, clinical practice, nursing homes and research. However, only few studies have compared different body fat estimation methods in older adults with inconsistent results. We estimated body fat percentage (%BF) and the level of agreement among dual energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA) and Durnin & Womersley’s skinfold eq. (SF) in older Brazilian adults aged 60 years and older from the Elderly Project Goiânia, Brazil.

Methods

The analytical sample comprised of 132 participants who had DXA data. The level of agreement for the %BF estimated by BIA, SF and DXA i.e. reference method, was examined using Bland and Altman’s and Lin’s plot.

Results

Overall, women had higher body mass index and %BF values measured by all three methods used. BIA and SF equation showed strong concordance to estimate body fat percentage in all participants (CCC = 0.857 and 0.861, respectively) and among women (CCC = 0.788 and 0.726, respectively) when compared to DXA. However, both methods underestimated body fat percentage in women and men with high body fat percentage. A strong level of agreement was observed between DXA and the anthropometric equation developed by Durnin & Womersley in men (CCC = 0.846), while BIA had a moderate concordance (CCC = 0.505) in this group.

Conclusion

The examined methods indicated different body fat estimates. However, the best agreement was observed between DXA and the anthropometric SF equation for men. Future research in older adults should develop new SF equations considering different ethnic groups.

Repository Describing an Aging Population to Inform Physiologically Based Pharmacokinetic Models Considering Anatomical, Physiological, and Biological Age-Dependent Changes

BACKGROUND

Aging is characterized by anatomical, physiological, and biological changes that can impact drug kinetics. The elderly are often excluded from clinical trials and knowledge about drug kinetics and drug-drug interaction magnitudes is sparse. Physiologically based pharmacokinetic modeling can overcome this clinical limitation but detailed descriptions of the population characteristics are essential to adequately inform models.

OBJECTIVE

The objective of this study was to develop and verify a population database for aging Caucasians considering anatomical, physiological, and biological system parameters required to inform a physiologically based pharmacokinetic model that included population variability.

METHODS

A structured literature search was performed to analyze age-dependent changes of system parameters. All collated data were carefully analyzed, and descriptive mathematical equations were derived.

RESULTS

A total of 362 studies were found of which 318 studies were included in the analysis as they reported rich data for anthropometric parameters and specific organs (e.g., liver). Continuous functions could be derived for most system parameters describing a Caucasian population from 20 to 99 years of age with variability. Areas with sparse data were identified such as tissue composition, but knowledge gaps were filled with plausible qualified assumptions. The developed population was implemented in Matlab^® and estimated system parameters from 1000 virtual individuals were in accordance with independent observed data showing the robustness of the developed population.

CONCLUSIONS

The developed repository for aging subjects provides a singular specific source for key system parameters needed for physiologically based pharmacokinetic modeling and can in turn be used to investigate drug kinetics and drug-drug interaction magnitudes in the elderly.

Changes in knee extension peak torque and body composition and their relationship with change in gait speed

BACKGROUND

Slow gait speed is a powerful predictor of disability in activities of daily living and mortality. Muscle strength and body composition change over time, but their changes differ by sex. How these parameters jointly affect gait speed decline is unknown. Understanding this association could help develop and evaluate the sex-specific effects of lifestyle interventions to delay gait speed decline in older adults. We assessed whether changes in strength (Δstrength), appendicular lean mass (ΔALM), and fat mass (Δfat) jointly relate to change in gait speed and whether the association differs by sex.

METHODS

The analytic sample comprised 575 women and 539 men aged 22-95 years enrolled in the Baltimore Longitudinal Study of Aging. Mean follow-up was 4.0 years. Measures included isometric knee extension strength, dual-energy X-ray absorptiometry-assessed ALM and fat mass, and gait speed from the 400 m fast pace walk. Sex-specific linear mixed models were adjusted for follow-up time and baseline age, race, height, ALM, fat mass, peak torque, and gait speed. We also included second-order interaction terms of the key predictive variables (e.g. Δstrength × ΔALM). To interpret the interactions, we estimated average gait declines using the 25th or 75th percentile of the two significant predictive variables and then assessed which condition relates to larger decline in gait speed.

RESULTS

In both sexes, independent of ΔALM and Δfat, larger decline in strength significantly related to larger decline in gait speed (P = 0.01 for both sexes). In men, interactions between Δstrength × ΔALM and Δfat by ΔALM were associated with change in gait speed; men with greater declines in both muscle strength and ALM or greater declines in both ALM and fat have steeper gait speed decline. In contrast, in women, the interaction between Δfat and ΔALM was associated with change in gait speed; women with an increase in fat mass combined with less decline in ALM have steeper gait speed decline.

CONCLUSIONS

While change in strength affects change in gait speed in both sexes, the effects of body composition change differ by sex. Dual-energy X-ray absorptiometry-based estimates of lean mass may be confounded by intramuscular fat. Future studies should examine sex-specific combined effects of change in strength and body composition on mobility using multiple techniques to measure body composition. Intervention studies should consider testing sex-specific interventions on body composition.

Age-associated changes of resting energy expenditure, body composition and fat distribution in Chinese Han males

Age-related alterations in whole body composition, particularly, reduced fat free mass (FFM) and increased fat mass (FM), lead to a progressive decline in resting energy expenditure (REE). Similarly, regional body composition and fat distribution changes with age might also contribute to an overall lower REE. This study investigated the influence of age on REE, regional body composition and fat distribution, including subcutaneous fat (SF) and visceral fat (VF), in a Chinese Han population as well as their contributions to age-related changes in REE. One hundred and two males aged 31-83 years old underwent dual-energy X-ray absorptiometry (DXA) which measured whole body and regional FM and FFM. SF and VF were measured by magnetic resonance imaging (MRI) and REE by indirect calorimetry. Age was significantly negatively correlated with REE (r = -0.37), total FFM (r = -0.25), upper limbs FFM (r = -0.32), lower limbs FFM (r = -0.34) and showed positive association with trunk FFM (β=0.926). FM, SF and VF decreased in older age groups after an initial rise up to 55-65 years. REE correlated positively to FM, FFM, SF, VF and showed significant association with age (β = -0.254) independent of age-associated changes in body composition. The regional alterations in body composition with age were explained by changes in trunk FFM (β = 0.926). Age-related decline in REE were not solely due to alterations in FM and FFM. Therefore, the changes in regional body composition, fat distribution and REE which occur during aging could be explained by disparities in race, ethnicity, diet, physical activity, and lower specific metabolic rates of FFM components.

An overview of assessment methodology for obesity-related variables in infants at risk

BACKGROUND

The first 2 years of a child's life are a particularly critical time period for obesity prevention.

AIM

An increasing amount of research across the world is aimed at understanding factors that impact early childhood obesity and developing interventions that target these factors effectively. With this growing interest, new and interdisciplinary research teams are developing to meet this research need. Due to rapid growth velocity during this phase of the lifespan, typical assessments used in older populations may not be valid or applicable in infants, and investigators need to be aware of the pros and cons of specific methodological strategies.

METHODS

This paper provides an overview of methodology available to assess obesity-related factors in the areas of anthropometry and body composition, nutrient intake, and energy expenditure in infants aged 0-2 years.

RESULTS

Gold standard measures for body composition, such as dual-energy X-ray absorptiometry (DXA) or other imaging techniques, are costly, require highly trained personnel, and are limited for research application. Nutrient intake methodology primarily includes surveys and questionnaires completed via parent proxy report. In terms of energy expenditure, methods of calorimetry are expensive and may not differentiate between different activities. Questionnaires or physical activity sensors offer another way of energy expenditure assessment. However, questionnaires have a certain recall bias, while the sensors require further validation.

CONCLUSIONS

Overall, in addition to understanding the pros and cons of each assessment tool, researchers should take into consideration the experience of the interdisciplinary team of investigators, as well as the cost and availability of measures at their institution.

The effects of truncal adiposity in forced spirometry: Sex differences

The aim of the current paper is to establish the influence of truncal fat accumulation on the spirometric results of a group of healthy individuals. A cross-sectional study of 305 healthy, non-smoking adult subjects (144 males, 161 females) was conducted. Forced spirometry and dual-energy X-ray absorptiometry to quantify body fat were performed. Partial correlation and multiple linear regression analyses were performed. In females, abdominal fat was negatively correlated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁). In males, thoracic fat was negatively correlated with respiratory variables, as was abdominal fat. In the multiple linear regression, FEV₁ was the spirometric parameter that showed higher R² values in both sexes. Truncal fat had a greater influence on FEV₁ than on FVC. In males, no significant differences between the influence of thoracic and abdominal fat on spirometric results were found, and total body fat was shown to have more influence than regional. In females, the influence of abdominal fat was higher.

The visceral adiposity index is associated with insulin sensitivity and IGF-I levels in adults with growth hormone deficiency

The visceral adiposity index, based on anthropometric and metabolic parameters, has been shown to be related to adipose tissue function and insulin sensitivity. We aimed to evaluate the performance of the visceral adiposity index in adult patients with growth hormone deficiency. We enrolled 52 patients(mean age 51 ± 13 years) with newly diagnosed growth hormone deficiency and 50 matched healthy subjects as controls at baseline. At baseline and after 12 and 24 months of treatment we evaluated anthropometric measures, lipid profile, glucose and insulin during an oral glucose tolerance test, hemoglobin A1c, homeostasis model assessment estimate of insulin resistance, quantitative insulin sensitivity check index, insulin sensitivity index Matsuda, insulin-like growth factor-I and visceral adiposity index. At baseline growth hormone deficiency patients showed higher waist circumference (p < 0.001), low-density lipoprotein cholesterol (p < 0.001) and visceral adiposity index (p = 0.003) with lower insulin sensitivity index (p = 0.007) and high-density lipoprotein cholesterol (p = 0.001) than controls. During growth hormone treatment we observed a significant increase in insulin-like growth factor-I (p < 0.001), high-density lipoprotein (p < 0.001) with a trend toward increase in insulin sensitivity index (p = 0.055) and a significant decrease in total cholesterol (p < 0.001) and visceral adiposity index (p < 0.001), while no significant changes were observed in other clinical and metabolic parameters. The visceral adiposity index was the only parameter that significantly correlated with growth hormone peak at diagnosis (p < 0.001) and with insulin-like growth factor-I and insulin sensitivity index both at diagnosis (p = 0.009 and p < 0.001) and after 12 (p = 0.026 and p = 0.001) and 24 months (p < 0.001 and p = 0.001) of treatment. The visceral adiposity index, which has shown to be associated with both insulin-like growth factor-I and insulin sensitivity, proved to be the most reliable index of metabolic perturbation, among the most common indexes of adiposity assessment and a marker of benefit during treatment in adult growth hormone deficiency patients.

Relationship of Muscle Mass Determined by DEXA with Spirometric Results in Healthy Individuals

INTRODUCTION

Muscle mass maybe a determining factor in the variability of spirometry results in individuals of the same sex and age who have similar anthropometric characteristics. The aim of this study was to determine the association between spirometric results from healthy individuals and their muscle mass assessed by dual energy X-ray absorptiometry (DEXA).

METHODS

A sample of 161 women and 144 men, all healthy non-smokers, was studied. Ages ranged from18 to77years. For each subject, spirometry results and total and regional lean mass values obtained by full body DEXA were recorded. A descriptive analysis of the variables and a regression analysis were performed to study the relationship between spirometric variables and lean body mass, correcting for age and body mass index (BMI).

RESULTS

In both sexes all muscle mass variables correlated positively and significantly with spirometric variables, and to a greater extent in men. After partial adjustment of correlations by age and BMI, the factor which best explains the spirometric variables is the total lean body mass in men, and trunk lean body mass in women.

CONCLUSIONS

In men, muscle mass in the lower extremities is most closely associated with spirometric results. In women, it is the muscle mass of the trunk. In both sexes muscle mass mainly affects FEV₁.

Age-Related Changes in Segmental Body Composition by Ethnicity and History of Weight Change across the Adult Lifespan

This study assessed age-related changes in body composition (specifically in trunk fat and appendicular lean masses), with consideration of body mass index (BMI) at age 20 years (BMI reference age, “BMIref”), ethnicity and lifetime weight change history. A cross-sectional dual-energy X-ray absorptiometry-based dataset was extracted from the U.S. National Health and Nutrition Examination Survey (NHANES) 1999–2004. Only European-American and African-American subjects were used (2705 men, 2527 women). For each gender and ethnicity, 6 analytic cases were considered, based on three BMIref categories (normal, overweight and obese, being 22, 27 and 30 kg/m², respectively) and two weight contexts (stable weight or weight gain across the lifespan). A nonparametric model was developed to investigate age-related changes in body composition. Then, parametric modelling was developed for assessing BMIref- and ethnicity-specific effects during aging. In the stable weight, both genders’ and ethnicities’ trunk fat (TF) increased gradually; body fat (BF) remained stable until 40 years and increased thereafter; trunk lean (TL) remained stable, but appendicular lean (APL) and body lean (BL) declined from 20 years. In the weight gain context, TF and BF increased at a constant rate, while APL, TL and BL increased until 40–50 years, and then declined slightly. Compared with European-American subjects of both genders, African-American subjects had lower TF and BF masses. Ethnic differences in body composition were quantified and found to remain constant across the lifespan.

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.

Relationships between body composition analysis measures in Greek women and US white women

We investigated the regional changes in body composition relative to age, in healthy Caucasian women living in the Mediterranean area. Body composition of total and subtotal body was measured, and fat mass (FM) ratios along with FM and lean mass (LM) indices were calculated in 330 women aged 20-85 years, using DXA. Data were compared with the NHANES reference database. Peak bone mineral density and bone mineral content of total body were 1.149 g/cm(2) and 2,209 g and were achieved between ages 41 and 50. Peak %FM of total body, FM index (FMI; FM/height(2)), FM of trunk to legs, and FM of trunk to limbs were 41.5%, 13.69 kg/m(2), 1.623, and 1.14, respectively. Peak %FM and FMI were achieved between 61 and 70 years. Unlike US counterparts, in our series, both FM ratios showed a propensity for women to accrue fat in the trunk following the android pattern of fat distribution. Peak LM index for total body (LMI; LM/height(2)) and limbs (ASMMI; appendicular skeletal muscle mass/height(2)) was 18.08 kg/m(2) and 7.33 kg/m(2), respectively, and was achieved between 61 and 70 years. For Greeks, the ASMMI was greater from 55 years onwards. Greek women have increasing bone mass in early adulthood followed by significant decline during fifties and onwards. Compared with US white women, Greek women have significantly greater truncal fat for all ages, implying a greater risk of obesity-associated diseases. Middle-aged and older Greek women have greater appendicular skeletal muscle mass, which may eliminate the overall risk of sarcopenic obesity.

Body composition assessment using DXA in six-year-old children: the 2004 Pelotas Birth Cohort, Rio Grande do Sul State, Brazil

The aim of this study was to describe fat (FM) and lean body mass (LBM) in six-year-old children from the 2004 Pelotas Birth Cohort, stratified by gender. Dual-Energy X-ray Absorptiometry was used to measure FM and LBM, FM and LBM indexes, and percentage (%) of FM and LBM. Mean measures of adiposity were higher among girls (6.3kg, 4.2kg/m2 and 23.4% vs. 5kg, 3.3kg/m2 and 18%) while LBM measures were higher among boys (19.3kg, 13kg/m2 and 78.5% vs. 17.7kg, 12.2kg/m2 and 73.2%). In both boys and girls mean measures of adiposity increased with socioeconomic status and maternal education. Mean measures of adiposity were higher among white-skinned children while %LBM was higher among black-skinned children. Preterm compared to full-term children showed lower mean measures of adiposity and LBM. Female sex, white skin color and higher socioeconomic conditions are associated with higher adiposity in childhood.

Body composition assessment in the infant

Body composition assessment provides a sharper picture of the human biological response to genetic and environmental influences than measures of body size and weight. Infant body composition is particularly important as a marker of fetal adaptation and developmental programming of subsequent health and disease, but until recently, the range of options for measuring infant body composition was relatively narrow. The purpose of this Toolkit: Methods in Human Biology review is to provide a comprehensive overview of methods of body composition methods currently used in infants 0 to 2 years of age, including anthropometric prediction equations, air displacement plethysmography (ADP), dual energy X-ray absorptiometry (DXA), bioelectrical impedance analysis (BIA), isotope dilution, and magnetic resonance imaging (MRI). Information on the reliability, validity, and accuracy of the methods is provided. Unique aspects of infant physiology and behavior create challenges for body composition assessment, but this review provides guidance on suitable testing approaches and environments that may aid researchers in this important area of investigation.

Long-term effects of recombinant human GH replacement in adults with GH deficiency: a systematic review

BACKGROUND

The beneficial effects of recombinant human GH (rhGH) therapy in GH deficient (GHD) adults are well-established in the short term. However, data documenting the effects during prolonged follow-up are relatively scarce.

OBJECTIVE

To evaluate the reported effects of rhGH replacement (≥5 years) in GHD adults on biochemical and anthropometric parameters, quality of life (QoL), bone metabolism, muscle strength, serious adverse events and mortality.

METHODS

We conducted a systematic literature search. Quality assessment of retrieved papers was performed using a quality assessment based on the modified STROBE statement.

RESULTS

We included 23 prospective studies with a rhGH treatment duration ranging from 5 to 15 years. Overall, beneficial effects were reported on QoL, body composition, lipid profile, carotid intima media thickness and bone mineral density. In contrast, the prevalence of the metabolic syndrome, glucose levels, BMI and muscle strength were not, or negatively, influenced. Most of the studies were uncontrolled, lacked the presence of a control group (of non-treated GHD patients), and reported no data on lipid-lowering and anti-diabetic medication. Overall mortality was not increased.

CONCLUSION

rhGH treatment in adult GHD patients is well-tolerated and positively affects QoL in the long term. However, the metabolic and cardiovascular effects during long-term treatment are variable. The low numbers of long-term studies and studied patients and lack of control data hamper definite statements on the efficacy of prolonged treatment. Therefore continuous monitoring of the effects of rhGH replacement to enable an adequate risk-benefit analysis that may justify prolonged, potentially life-long, treatment is advisable.

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

BACKGROUND & AIMS

The aim of this work was to provide a complete profile of body composition (BC) in healthy subjects and to investigate age and gender-related differences by dual-energy X-ray absorptiometry (DXA) and its latest developments.

METHODS

Italian volunteers among blood donors were enrolled in 5 different age bands (from 18 to 70 years old) to reach the threshold of 25 males and 25 females per single band (total: 250 subjects). All non-obese subjects who satisfied selective inclusion criteria were measured for weight and height and submitted to DXA, to determine fat mass (FM), non-bone lean mass (LM), bone mineral content and density, at regional and whole-body level. Moreover, the assessment of android visceral FM was performed by a new software.

RESULTS

A decrease in LM and increase in FM was observed with ageing, although the phenomenon was proved to be attenuated in women. The central and visceral redistribution of FM was also shown along lifetime, but women were not affected as men by this change.

CONCLUSIONS

This paper is a report on the status of healthy Italian subjects in their adulthood, to be used as a reference for future investigations on physiology, pathological human conditions, and differences between countries.

Comparison of regional body composition and its relation with cardiometabolic risk between BMI-matched young and old subjects

OBJECTIVE

Difference in regional body composition between young and old people may be related with differential cardiometabolic risks. We investigated regional body composition in BMI-matched young and old subjects to compare its relation with cardiometabolic risk.

METHODS

We recruited 1:3 gender- and BMI-matched 86 young subjects (mean age 27.3 ± 2.9 years) and 258 older subjects (75.6 ± 8.2 years) from a community. Abdominal visceral (VAT) and subcutaneous adipose tissue (SAT) and muscle area at mid-thigh level were evaluated by computed tomography. Fat depots in the gynoid area and lower extremity were measured by dual energy X-ray absorptiometry. Adiponectin, retinol binding protein-4 (RBP-4), and C-reactive protein (CRP) concentrations, pulse wave velocity (PWV) and ankle-brachial index (ABI) were measured for cardiometabolic risk.

RESULTS

VAT was greater in older subjects while SAT was almost the same, resulting in twice higher VAT/SAT ratio in older men and women (1.03 ± 0.37 and 0.57 ± 0.18) than younger counterparts (0.55 ± 0.24 and 0.23 ± 0.23) (both P < 0.01). Fat mass in the gynoid area and lower extremity was smaller in older subjects than younger subjects. The VAT correlated with adiponectin level negatively and RBP-4 level positively while gynoid fat correlated with them in opposite direction. The CRP levels negatively correlated with mid-thigh muscle in older subjects. Older subjects had higher PWV and lower ABI compared to BMI-matched younger counterparts.

CONCLUSION

In conclusion, older adults in this cohort had increased visceral fat and decreased gynoid and lower extremity fat, along with less muscle mass. These findings may help explain the worse cardiometabolic profiles in the elderly who have the same BMI as the young.

Region-specific fat mass and muscle mass and mortality in community-dwelling older men and women

BACKGROUND

Increased mortality risk at low body mass index values is well established for older persons. It is, however, unclear how the underlying body mass components (fat and muscle mass - FM and MM, respectively) are associated with mortality in old age.

OBJECTIVE

This study aimed to examine the mortality risk of four body composition measures (appendicular skeletal MM, leg, arm and trunk FM) with 12-year mortality in community-dwelling older men and women. As a secondary objective, the influence of cancer, obstructive lung disease, smoking and previous weight loss on these associations was examined.

METHODS

Data were used from the Longitudinal Aging Study Amsterdam, a random population-based cohort study (55-85 years) in the Netherlands. Body composition was determined in 1995-1996 by dual energy X-ray absorptiometry. The present study included 477 community-dwelling persons aged ≥65 years who were followed until 2007 for their vital status.

RESULTS

Twelve-year mortality rates were 133/242 (55%) in men and 92/235 (39%) in women. Since most associations were U- or J-shaped, only observations below the sample mean were included to calculate hazard ratios (HRs) per one SD lower value. Adjusted for height, age and each other, lower appendicular skeletal MM [HR 1.59 (95% CI: 1.04-2.42)] and lower leg FM [1.68 (1.04-2.72)] in men and lower trunk FM [1.61 (1.02-2.53)] in women were associated with an increased mortality risk. Associations attenuated and became statistically nonsignificant in men after adjustment for cancer, obstructive pulmonary disease and smoking and in women after additional adjustment for previous 3-year weight change.

CONCLUSIONS

In older men, lower MM and lower leg FM are associated with an increased mortality risk, while in older women only lower trunk FM is associated with an increased risk. The causality of these associations is debated. Suggested sex differences deserve further study.

Low-fat dairy intake and body weight and composition changes in college students

Dairy calcium may help prevent excess weight gain and obesity when consumed in adequate amounts (three or more servings per day) and combined with energy balance. This prospective cohort study was conducted to evaluate dairy intake and examine the association between low-fat dairy intake and body weight and composition changes in college students. Seventy-six college students (65 women and 11 men; mean age+/-standard error [SE]=19.2+/-0.2 years) completed 7-day food records, body height (cm), weight (kg), and waist circumference (cm) measurements twice (September 2004 and April 2005). Percentage of truncal fat and percentage of total body fat were measured by dual-energy x-ray absorptiometry. One-way multivariate analysis of covariance was conducted. Overall (mean+/-SE) total dairy (1.4+/-0.1 servings/day), low-fat dairy (0.5+/-0.1 servings/day), and calcium (815+/-41 mg/day) intakes were low. Subjects who consumed a higher amount of low-fat dairy products (mean+/-SE=0.8+/-0.1 servings/day) had better diet quality, gained less body weight, and had reductions in waist circumference, percentage truncal fat, and percentage total body fat compared to those with lower intake (mean+/-SE=0.1+/-0.0 servings/day). Low-fat dairy intake may be associated with better diet quality and weight management in college students. Nutrition interventions in young adults should promote low-fat dairy intake as part of an overall healthful lifestyle.