Dual energy X-ray absorptiometry assessment of fat mass distribution and its association with the insulin resistance syndrome

Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions

Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.

Discriminant Model for Insulin Resistance in Type 2 Diabetic Patients

Introduction: Patients with type 2 diabetes mellitus tend to have insulin resistance, a condition that is evaluated using expensive methods that are not easily accessible in routine clinical practice. Objective: To determine the anthropometric, clinical, and metabolic parameters that allow for the discrimination of type 2 diabetic patients who have insulin resistance from those who do not. Methods: A cross-sectional analytical observational study was carried out in 92 type 2 diabetic patients. A discriminant analysis was applied using the SPSS statistical package to establish the characteristics that differentiate type 2 diabetic patients with insulin resistance from those without it. Results: Most of the variables analyzed in this study have a statistically significant association with the HOMA-IR. However, only HDL-c, LDL-c, glycemia, BMI, and tobacco exposure time allow for the discrimination of type 2 diabetic patients who have insulin resistance from those who do not, considering the interaction between them. According to the absolute value of the structure matrix, the variable that contributes most to the discriminant model is HDL-c (-0.69). Conclusions: The association between HDL-c, LDL-c, glycemia, BMI, and tobacco exposure time allows for the discrimination of type 2 diabetic patients who have insulin resistance from those who do not. This constitutes a simple model that can be used in routine clinical practice.

The Impact of Long-term Physical Inactivity on Adipose Tissue Immunometabolism

CONTEXT

Adipose tissue and physical inactivity both influence metabolic health and systemic inflammation, but how adipose tissue responds to chronic physical inactivity is unknown.

OBJECTIVE

This work aimed to characterize the impact of chronic physical inactivity on adipose tissue in healthy, young males.

METHODS

We collected subcutaneous adipose tissue from 20 healthy, young men before and after 60 days of complete bed rest with energy intake reduced to maintain energy balance and fat mass. We used RNA sequencing, flow cytometry, ex vivo tissue culture, and targeted protein analyses to examine adipose tissue phenotype.

RESULTS

Our results indicate that the adipose tissue transcriptome, stromal cellular compartment, and insulin signaling protein abundance are largely unaffected by bed rest when fat mass is kept stable. However, there was an increase in the circulating concentration of several adipokines, including plasma leptin, which was associated with inactivity-induced increases in plasma insulin and absent from adipose tissue cultured ex vivo under standardized culture conditions.

CONCLUSION

Physical inactivity-induced disturbances to adipokine concentrations such as leptin, without changes to fat mass, could have profound metabolic implications outside a clinical facility when energy intake is not tightly controlled.

Metabolic flexibility differs by body composition in adults

BACKGROUND & AIMS

With the rise of global cardiometabolic diseases, it is important to investigate risk factors such as obesity. Metabolic flexibility, the ability to maintain metabolic homeostasis following an acute challenge, can reflect cardiometabolic health. We investigated the association between body composition and the metabolic flexibility following meal consumption in an adult population.

METHODS

In this study of 1027 participants (mean age 44.0 y ± SD 4.2 y), we administered a mixed-macronutrient meal challenge. Fasting and 2-h postprandial plasma were assayed for lipids, glycemic, and inflammation biomarkers. We characterized metabolic flexibility through meal-induced biomarker responses (%Δ, the difference between postprandial and fasting concentrations, divided by fasting concentration). We then compared the responses by sex-specific tertiles of body mass index (BMI) and percent body fat.

RESULTS

With every unit (kg/m²) increase in BMI, %Δ (95% confidence interval) increased by 0.17% (0.09, 0.26%) for total cholesterol, 0.31% (0.07, 0.54%) for triglycerides, and 0.11% (0.01, 0.20%) for apoA-I, whereas insulin elevation was reduced (-6.30%; -8.41, -4.20%), and the reduction in leptin was attenuated (0.64%; 0.25, 1.05%). With each unit (percent) increase in body fat, we observed similar changes in the %Δ of total cholesterol and leptin but not in triglycerides, apoA-I, or insulin. Glucose response increased by 0.29% (0.06, 0.51%) as body fat increases by one unit.

CONCLUSION

Metabolic flexibility, as assessed by biomarker responses to an acute physiological meal challenge, differed by body composition. These findings may help elucidate the pathways through which obesity contributes to cardiometabolic diseases.

Divergent immunometabolic changes in adipose tissue and skeletal muscle with ageing in healthy humans

KEY POINTS

Ageing is associated with increased systemic inflammation and metabolic dysfunction that contributes to the development of age-associated diseases. The role of adipose tissue in immunometabolic alterations that take place with ageing is unknown in humans. We show, in healthy, active and lean older adults, that adipose tissue, but not skeletal muscle, displays considerable pro-inflammatory transcriptomic, cellular and secretory changes, as well as a reduction in insulin signalling proteins compared to younger adults. These findings indicate that adipose tissue undergoes substantial immunometabolic alterations with ageing, and that these changes are tissue-specific and more profound than those observed in skeletal muscle or in the circulation. These results identify adipose tissue as an important tissue in the biological ageing process in humans, which may exhibit signs of immunometabolic dysfunction prior to systemic manifestation.

ABSTRACT

Ageing and obesity are both characterized by inflammation and a deterioration in metabolic health. It is now clear that adipose tissue plays a major role in inflammation and metabolic control in obesity, although little is known about the role of adipose tissue in human ageing. To understand how ageing impacts adipose tissue, we characterized subcutaneous adipose tissue and skeletal muscle samples from twelve younger (27 ± 4 years [Young]) and twelve older (66 ± 5 years [Old]) active/non-obese males. We performed a wide-range of whole-body and tissue measures, including RNA-sequencing and multicolour flow cytometry. We also measured a range of inflammatory and metabolic proteins in the circulation and their release by adipose tissue, ex vivo. Both adipose tissue and muscle had ∼2-fold more immune cells per gram of tissue with ageing. In adipose tissue, this immune cell infiltration was driven by increased memory/effector T-cells, whereas, in muscle, the accumulation was driven by memory/effector T-cells and macrophages. Transcriptomic analysis revealed that, with ageing, adipose tissue, but not muscle, was enriched for inflammatory transcripts/pathways related to acquired and innate immunity. Ageing also increased the adipose tissue pro-inflammatory secretory profile. Insulin signalling protein content was reduced in adipose tissue, but not muscle. Our findings indicate that adipose tissue undergoes substantial immunometabolic changes with ageing in humans, and that these changes are tissue-specific and more profound than those observed in the circulation and skeletal muscle.

Body Composition is Associated With Islet Function After Pancreatectomy and Islet Autotransplantation for Pancreatitis

CONTEXT

Body composition in total pancreatectomy with islet autotransplantation (TPIAT) has never been studied.

OBJECTIVE

Determine whether presurgical body composition is associated with islet function and insulin sensitivity after TPIAT.

METHODS

In 88 adults undergoing TPIAT (median age 41.0 years, IQR 32.8-48.0), beta-cell function and insulin sensitivity were assessed using mixed meal tolerance test and frequent sample intravenous glucose tolerance test before surgery and 12 and 18 months afterward. Body composition was measured by dual x-ray absorptiometry. Analyses used linear and logistic regression.

RESULTS

Before surgery, 8 individuals (9.1%) were underweight, 40 (45.5%) normal weight, 20 (22.7%) overweight, and 20 (22.7%) obese. Overweight/obese patients had higher area under the curve C-peptide and lower insulin sensitivity index. Baseline body weight was positively associated with first-phase insulin secretion (AIRg) at 12 months (average 38.5 [SE 17.1] mU/L/min higher per extra kg; P = 0.03) and 18 months (38.3 [18.5]; P = 0.04), while baseline lean mass was inversely associated with AIRg at 12 months (-0.05 [0.02] per extra kg; P = 0.01) and 18 months (-0.05 [0.02]; P = 0.03). Percent gynoid fat was inversely associated with disposition index at 18 months (-206.0 [97.2] per extra percent; P = 0.04). Percent body fat and percent gynoid fat were associated with glucose effectiveness index at 18 months (1.9 × 10-3 [0.9 × 10-3] per extra percent; P = 0.04 and -1.96 × 10-3 [0.8 × 10-3]; P = 0.02, respectively). Insulin independence was not significantly associated with body weight or composition.

CONCLUSIONS

Half of these chronic pancreatitis patients were overweight/obese; underweight was uncommon. Preoperative body weight and composition were associated with islet function but not insulin independence after TPIAT.

Body composition assessment in athletes with physical impairment who have been practicing a wheelchair sport regularly and for a prolonged period

BACKGROUND

Today several important aspects related to the impact of long-term wheelchair sports on whole-body and regional body composition in athletes with a physical impairment are poorly understood.

OBJECTIVE

This cross-sectional study aimed at investigating the impact of the long-term regular practice of wheelchair sports on body composition in male wheelchair athletes (WA) as compared with both non-athletic participants with a physical impairment and non-athletic able-bodied participants.

METHODS

Nine WA were each matched pairwise by age, duration of injury and body mass index (BMI) with a participant with a physical impairment not engaged in any wheelchair sport (N-WA) and by age and BMI with an able-bodied (AB) participant. Whole-body and regional bone mineral content (BMC), fat-free soft tissue mass (FFSTM), fat mass (FM) and percentage FM (%FM) were assessed by means of Dual-Energy X-ray Absorptiometry.

RESULTS

WA had significantly lower FM and %FM vs. N-WA at the whole-body level (P = 0.01 for both) and in the trunk region (P = 0.001 and P = <0.001, respectively). The only difference in body composition variables between WA and AB was found in the legs where WA had significantly higher FM (P = 0.014) along with lower BMC (P = 0.009) and FFSTM (P = 0.005) vs. AB in the legs.

CONCLUSIONS

The results of the present study showed that the regular, long-term practice of wheelchair sport may be associated with beneficial body composition adaptations in athletes with a physical impairment at the whole-body and trunk level.

Adipose Tissue Distribution, Inflammation and Its Metabolic Consequences, Including Diabetes and Cardiovascular Disease

Adipose tissue plays essential roles in maintaining lipid and glucose homeostasis. To date several types of adipose tissue have been identified, namely white, brown, and beige, that reside in various specific anatomical locations throughout the body. The cellular composition, secretome, and location of these adipose depots define their function in health and metabolic disease. In obesity, adipose tissue becomes dysfunctional, promoting a pro-inflammatory, hyperlipidemic and insulin resistant environment that contributes to type 2 diabetes mellitus (T2DM). Concurrently, similar features that result from adipose tissue dysfunction also promote cardiovascular disease (CVD) by mechanisms that can be augmented by T2DM. The mechanisms by which dysfunctional adipose tissue simultaneously promote T2DM and CVD, focusing on adipose tissue depot-specific adipokines, inflammatory profiles, and metabolism, will be the focus of this review. The impact that various T2DM and CVD treatment strategies have on adipose tissue function and body weight also will be discussed.

Physical Activity and Insulin Resistance in 6,500 NHANES Adults: The Role of Abdominal Obesity

This cross-sectional investigation studied differences in insulin resistance across levels of physical activity in 6,500 US adults who were randomly selected as part of the National Health and Nutrition Examination Survey (NHANES). Another important objective was to determine the influence of abdominal obesity on the physical activity and insulin resistance relationship. MET-minutes were utilized to quantify total activity based on participation in 48 different physical activities. Two strategies were employed to categorize levels of physical activity: one was based on relative MET-minutes (quartiles), and the other approach was based on the US physical activity guidelines. Insulin resistance was indexed using the homeostatic model assessment (HOMA). Abdominal obesity was indexed using waist circumference. Effect modification was tested by dividing waist circumferences into sex-specific quartiles and then evaluating the relationship between physical activity and HOMA-IR within each quartile separately. Results showed that relative physical activity level was associated with HOMA-IR after controlling for demographic and demographic and lifestyle covariates (F = 11.5, P < 0.0001 and F = 6.0, P=0.0012, respectively). Adjusting for demographic and demographic and lifestyle covariates also resulted in significant relationships between guideline-based activity and HOMA-IR (F = 8.0, P < 0.0001 and F = 4.9, P=0.0017, respectively). However, statistically controlling for differences in waist circumference with the other covariates nullified the relationship between total physical activity and HOMA-IR. Effect modification testing showed that when the sample was delimited to adults with abdominal obesity (Quartile 4), relative (F = 5.6, P=0.0019) and guideline-based physical activity (F = 3.7, P=0.0098) and HOMA-IR were significantly associated. Physical activity and HOMA-IR were not related within the other three quartiles. In conclusion, it appears that differences in physical activity may play a meaningful role in insulin resistance in those with abdominal obesity, but total activity does not seem to account for differences in insulin resistance among US adults with smaller waists.

A TUG Value Longer Than 11 s Predicts Fall Risk at 6-Month in Individuals with COPD

Risk of a fall is increased in individuals with chronic obstructive pulmonary disease (COPD), and is usually evaluated using the Berg Balance Scale (BBS), but this is difficult to perform in everyday clinical practice. We aimed to prospectively predict short-term fall recurrence in COPD patients using a predetermined cut-off value of the Timed Up and Go test (TUG). In stable COPD patients, we collected self-reported records of the number of falls in the previous year, and measured TUG and BBS scores for each individual. Records of fall recurrence were obtained prospectively at 6-months after the initial evaluation. Among the 50 patients recruited, 23 (46%) had at least one fall during the past year. The optimal diagnosis value for the TUG to detect a fall was 10.9 s with a sensitivity of 100% and a specificity of 97%. A cut-off of 11 s predicted fall recurrence with high sensitivity and specificity (93% and 74%, respectively). The TUG as well as the BBS score detected fallers, and a cut-off value of 11 s predicted fall recurrence. TUG could be easily incorporated into the scheduled functional evaluations of COPD patients, could predict the risk of a fall and when appropriate, could guide specific balance training exercises to prevent fall.

DXA-Determined Regional Adiposity Relates to Insulin Resistance in a Young Adult Population with Overweight andObesity

Obesity is a well-established risk factor for insulin resistance and type 2 diabetes mellitus, and body fat distribution has important implications for this metabolic risk. In this cross-sectional study, we used dual X-ray absorptiometry body composition data from 123 young adult participants with overweight or obesity, and correlatedwith 2 indices of insulin resistance calculated from oral glucose tolerance tests. Participants were 70% women, with mean (standard error) age 30.1 (0.6) yr, body mass index (BMI) 34.0 (0.6) kg/m², homeostatic model assessment of insulin resistance (HOMA-IR) of 2.1 (0.2), and Matsuda insulin sensitivity index (Matsuda ISI) of 5.8 (0.4). In women, the strongest correlations were observed with the android-to-gynoid ratio (r = 0.52, p < 0.001 for HOMA-IR; r = -0.46, p < 0.001 for Matsuda ISI), and these correlations remained significant after adjustment for BMI. For men, the strongest correlations were with android fat mass (r = 0.40, p = 0.01 for HOMA-IR; r = -0.37, p = 0.02 for Matsuda ISI). Visceral adipose tissue was correlated with HOMA-IR and Matsuda ISI in women, and only with Matsuda ISI in men. BMI correlated with HOMA-IR and with Matsuda ISI in both women and men. Regional adiposity determined by dual X-ray absorptiometry correlates with indices of insulin resistance in sedentary young adults with overweight and obesity.

Rationale, design and study protocol of the randomised controlled trial: Diabetes Interventional Assessment of Slimming or Training tO Lessen Inconspicuous Cardiovascular Dysfunction (the DIASTOLIC study)

INTRODUCTION

Despite their young age and relatively short duration of disease, younger adults with type 2 diabetes (T2D) already have diastolic dysfunction and may be at risk of incipient heart failure. Whether weight loss or exercise training improve cardiac dysfunction in people with T2D remains to be established.

METHODS AND ANALYSIS

Prospective, randomised, open-label, blind endpoint trial. The primary aim of the study is to determine if diastolic function can be improved by either a meal replacement plan or a supervised exercise programme, compared with guideline-directed care. A total of 90 obese participants with T2D (aged 18-65 years), diabetes duration <12 years and not on insulin treatment will be randomised to either guideline-directed clinical care with lifestyle coaching, a low-energy meal replacement diet (average ≈810 kcal/day) or a supervised exercise programme for 12 weeks. Participants undergo glycometabolic profiling, cardiopulmonary exercise testing, echocardiography and MRI scanning to assesses cardiac structure and function and dual-energy X-ray absorptiometry scanning for body composition. Key secondary aims are to assess the effects of the interventions on glycaemic control and insulin resistance, exercise capacity, blood pressure, changes in body composition and association of favourable cardiac remodelling with improvements in weight loss, exercise capacity and glycometabolic control.

ETHICS AND DISSEMINATION

The study has full ethical approval, and data collection was completed in August 2018. The study results will be submitted for publication within 6 months of completion.

TRIAL REGISTRATION NUMBER

NCT02590822; Pre-results.

Contribution of Adipose Tissue Inflammation to the Development of Type 2 Diabetes Mellitus

The objective of this comprehensive review is to summarize and discuss the available evidence of how adipose tissue inflammation affects insulin sensitivity and glucose tolerance. Low-grade, chronic adipose tissue inflammation is characterized by infiltration of macrophages and other immune cell populations into adipose tissue, and a shift toward more proinflammatory subtypes of leukocytes. The infiltration of proinflammatory cells in adipose tissue is associated with an increased production of key chemokines such as C-C motif chemokine ligand 2, proinflammatory cytokines including tumor necrosis factor α and interleukins 1β and 6 as well as reduced expression of the key insulin-sensitizing adipokine, adiponectin. In both rodent models and humans, adipose tissue inflammation is consistently associated with excess fat mass and insulin resistance. In humans, associations with insulin resistance are stronger and more consistent for inflammation in visceral as opposed to subcutaneous fat. Further, genetic alterations in mouse models of obesity that reduce adipose tissue inflammation are-almost without exception-associated with improved insulin sensitivity. However, a dissociation between adipose tissue inflammation and insulin resistance can be observed in very few rodent models of obesity as well as in humans following bariatric surgery- or low-calorie-diet-induced weight loss, illustrating that the etiology of insulin resistance is multifactorial. Taken together, adipose tissue inflammation is a key factor in the development of insulin resistance and type 2 diabetes in obesity, along with other factors that likely include inflammation and fat accumulation in other metabolically active tissues. © 2019 American Physiological Society. Compr Physiol 9:1-58, 2019.

Diagnosis and follow-up of type 2 diabetes in women with PCOS: a role for OGTT?

Polycystic ovary syndrome (PCOS) is common in premenopausal women. The majority of women with PCOS have insulin resistance and the risk of type 2 diabetes mellitus (T2D) is higher in women with PCOS compared to controls. In non-pregnant women with PCOS, glycemic status may be assessed by oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) or HbA1c. OGTT has been reckoned gold standard test for diagnosing T2D, but OGTT is rarely used for diagnostic purpose in other non-pregnant individuals at risk of T2D, apart from PCOS. OGTT has questionable reproducibility, and high sensitivity of the 2-h glucose value is at the expense of relatively low specificity, especially regarding impaired glucose tolerance (IGT). Furthermore, lean women with PCOS are rarely diagnosed with T2D and only few percent of normal-weight women have prediabetes. Glycemic status is necessary at diagnosis and during follow-up of PCOS, especially in women with high risk of T2D (obesity, previous gestational diabetes (GDM)). We suggest that OGTT should be used in the same situations in PCOS as in other patient groups at risk of T2D. OGTT is indicated for diagnosing GDM; however, OGTT during pregnancy may not be indicated in lean women with PCOS without other risk factors for GDM.

Age- and sex-related differences in body composition in healthy subjects aged 18 to 82 years

Significant changes in body composition are known to occur with aging. The aim of the present study was to provide a normative reference of body composition and to investigate age and sex-related differences in healthy subjects by multifrequency bioelectrical impedance analyzer (BIA).A cross-sectional study was conducted on a sample of 3451 healthy Chinese adults, 1611 males and 1840 females. The volunteers were enrolled in 5 different age bands (18-30, 31-40, 41-50, 51-60, 60+). All subjects were measured for weight and height and submitted to BIA, to determine body composition. Body composition measures accounted for differences between men and women.A decrease in fat-free mass and increase in percent body fat was observed with aging, although the phenomenon was proved to be attenuated in women. The central and visceral redistribution of fat mass was also shown along lifetime.This study is a report on body composition of healthy subjects, to be used as an important data for future investigations and differences between nationalities and countries.

Different Associations of Trunk and Lower-Body Fat Mass Distribution with Cardiometabolic Risk Factors between Healthy Middle-Aged Men and Women

The aim of this study was to assess whether the gender-specific pattern of fat mass (FM) distribution is related to gender differences in cardiometabolic risk factors. 207 healthy middle-aged Japanese were included in the study. We measured FM in the total body, trunk, and lower-body with dual-energy X-ray absorptiometry (DXA). The percentage of trunk FM (TFM) and lower-body FM (LFM) is noted as %TFM and %LFM, respectively. Other measurements included glucose and insulin during oral glucose tolerance test (OGTT), leptin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor-α (TNF-α), C-reactive protein (CRP), and systemic oxidative stress marker. Arterial properties were indicated by cardio-ankle vascular index (CAVI) and intima-media thickness (IMT) of the common carotid artery. The results showed that %TFM is higher whereas %LFM is lower in men than in women and men have a more atherogenic cardiometabolic profile. In both genders, %TFM (%LFM) is related to an unfavorable (favorable) cardiometabolic profile. In particular, the relation between %LFM and OGTT-derived insulin sensitivity index is stronger in women than in men. These findings suggested that in relatively healthy adults, android and gynoid pattern of FM distribution contributes to gender differences in cardiometabolic risk factors.

An evaluation of low volume high-intensity intermittent training (HIIT) for health risk reduction in overweight and obese men

ᅟ

Both sprint interval training (SIT) and high-intensity intermittent training (HIIT) have been described as time-efficient strategies for inducing favourable metabolic and cardiorespiratory adaptations in healthy and diseased participants.

Background

To date, little attention has been given to profiling the potential health benefits of HIIT or modified HIIT training within overweight and obese cohorts with particular focus on inflammation. Within this pilot trial, we tested the hypothesis that 6 sessions of HIIT performed over 2 weeks with 1–2 days’ rest would improve aerobic capacity, glucose metabolism and inflammatory profile in an overweight and obese male cohort. Additionally, we profiled the potential health benefits of 4 HIIT sessions performed over the same period.

Methods

18 overweight or obese males (BMI = 31.2 ± 3.6; V̇O₂ = 30.3 ± 4.4 ml.kg.min^-1) were studied before and 72 h after HIIT. Training sessions consisted of 10 x 1 min intervals at 90% HR_peak separated by 1 min recovery periods. Exercise was performed either 6 (group 1, n = 8) or 4 (group 2, n = 10) times over a 2 week period.

Results

After training no changes were detected from baseline for body composition, aerobic capacity, glucose metabolism or inflammatory profile (p > 0.05) in either group.

Conclusion

Both 6 and 4 sessions of HIIT performed over a 2-week period are ineffective in improving selected health markers within an overweight and obese cohort.

Trial registration

This trial reports data from human participants and was retrospectively registered on 22/02/2017 with the ISRCTN registry, trial number ISRCTN90672085.

Total and regional adiposity measured by dual-energy X-ray absorptiometry and mortality in NHANES 1999-2006

OBJECTIVE

Associations of overall and regional body fat measured by dual-energy X-ray absorptiometry with total and cause-specific mortality in the National Health and Nutrition Examination Survey (NHANES) 1999-2006 were investigated.

METHODS

This study included 9,471 participants (≥20 years) free of major chronic diseases at baseline. Death information was obtained from the National Death Index (mean follow-up duration: 8.8 years).

RESULTS

A total of 682 participants died after 12 months since baseline, with 206 and 170 deaths attributed to cardiovascular diseases (CVD) and cancer, respectively. The second quartile of fat mass percentages (FM%) was used as the reference to account for potential nonlinearity. In the multivariate-adjusted model, participants in the highest quartile of total FM% had increased total mortality; hazard ratio (HR; 95% confidence interval, 95% CI) was 1.48 (1.07-2.04; P < 0.05). Higher total and trunk FM%, but not leg FM%, were significantly associated with an increased CVD mortality; HRs (95% CIs) in the highest quartiles of total, trunk, and leg FM% were 2.24 (1.17-4.31), 1.93 (1.02-3.66), and 1.50 (0.77-2.94), respectively.

CONCLUSIONS

Higher total body fat was associated with increased total mortality in U.S. adults. Higher total and trunk fat contents were also associated with increased CVD mortality, although fat accumulation in the lower body was not an independent predictor of mortality.

Moderate to vigorous physical activity, not sedentary time, is associated with total and regional adiposity in a sample of UK adults at risk of type 2 diabetes

How sedentary time (ST) relates to total and regional adiposity and whether these associations are independent of moderate- to vigorous-intensity physical activity (MVPA) are of clinical and public health interest. We assessed the relationship between objectively measured MVPA, ST and ST breaks in adults at risk of type 2 diabetes. The sample consisted of 163 adults (37-75 years) recruited from primary care. Dual energy x-ray absorptiometry (iDXA, GE Corp) was used to estimate total and regional (appendages and trunk) fat mass as well as fat mass in the abdominal (android) and hip/thigh (gynoid) regions. The Actigraph GT3X was worn for 7 days (participants with  ⩾4 valid days included herein) and published cut-points were applied to 15 s epoch data to estimate mean MVPA, ST and breaks in ST. Multiple regression investigated associations between both ST and MVPA with total and regional adiposity without and with adjustment for known and potential confounders (including total lean mass) and for each other. MVPA was negatively and significantly associated with total (b  =  -62; p  =  0.002), and regional (p  <  0.05) adiposity before and after adjusting for confounders including ST. Although ST was positively and significantly associated with total (b  =  46.4; p  =  0.002) and regional adiposity (all p  ⩽  0.007), these relationships disappeared after adjustment for MVPA (p  >  0.05). Sedentary breaks were not significantly related to adiposity before or after adjustment. An age-by-MVPA interaction for total, android, gynoid and trunk fat revealed that MVPA did not remain significant when controlling for ST and other covariates in the adults over 65 years old. In this sample of adults at risk of type 2 diabetes, MVPA, and not ST, was associated with total and regional adiposity after adjustment for each other. However, in older adults at risk of T2D weight related benefits may be gained from reducing daily ST and increasing MVPA.

Appetite-regulating hormones in early life and relationships with type of feeding and body composition in healthy term infants

Introduction

Body composition in early life influences development of obesity during childhood and beyond. Appetite-regulating hormones (ARH) play a role in regulation of food intake and might thus influence body composition in later life. Studies on associations between ARH and body composition in early life are limited.

Methods

In 197 healthy term infants, we measured serum fasting levels of ghrelin, leptin, insulin, glucose-dependent insulinotropic peptide (GIP), pancreatic polypeptide (PP) and peptide YY (PYY) at 3 months and in 41 infants also at 6 months and their associations with type of feeding and longitudinal fat mass percentage (FM%) measured by air displacement plethysmography at 1, 3 and 6 months and abdominal visceral and subcutaneous fat, measured by ultrasound, at 3 and 6 months.

Results

Infants with formula feeding for 3 months had significantly higher serum levels of ghrelin, leptin, insulin, GIP and PP (p = 0.026, p = 0.018, p = 0.002, p < 0.001, resp.) and lower serum levels of PYY (p = 0.002) at 3 months than breastfed infants. Leptin and ghrelin correlated positively with FM% at 3 months and insulin with change in FM% between 1 and 3 months (r = 0.40, p < 0.001, r = 0.23, p < 0.05, r = 0.22, p < 0.01, resp.). Leptin at 3 months correlated with subcutaneous fat at 3 months (r = 0.23, p < 0.001), but not with visceral fat. Other ARH did not correlate with body composition.

Conclusion

Formula-fed infants had a different profile of ARH than breastfed infants, suggesting that lower levels of ghrelin, leptin and insulin in breastfed infants contribute to the protective role of breastfeeding against obesity development. Leptin, ghrelin and insulin were associated with fat mass percentage or its changes.

Association of adiposity, measured by skinfold thickness, with parental history of diabetes in a South Indian population: data from CURES-114

PURPOSE OF THE STUDY

To look at the association of central and peripheral skinfold thickness with parental history of diabetes in subjects without diabetes.

METHODS

Subjects with no parental history of diabetes (n=1132), subjects with one parent with diabetes (n=271) and subjects with both parents with diabetes (n=51) were recruited from the Chennai Urban Rural Epidemiological Study (CURES) conducted between 2001 and 2003. Biceps, triceps, medial calf, mid-thigh, chest, abdomen, mid-axillary, suprailiac and subscapsular sites were measured with Lange skinfold callipers.

RESULTS

Trunk fat measurements, such as chest (p=0.020), mid-axillary (p=0.005), suprailiac (p=0.014), subscapsular (p<0.001) and abdomen (p=0.010) skinfolds, were highest in subjects with both parents with diabetes followed by those with one parent with diabetes, and lowest in those with no parental history of diabetes. However, the peripheral fat measurements, ie, biceps, triceps, medial calf and mid-thigh, were not significantly different between the study groups. Total truncal and peripheral fat skinfold thicknesses showed a significant positive association with other indices of obesity such as body mass index (BMI) and waist circumference in relation to trunk fat (BMI: r=0.748, p<0.001; waist: r=0.776, p<0.001) and peripheral fat (BMI: r=0.681, p<0.001; waist: r=0.569, p<0.001).

CONCLUSIONS

A significant association was observed between truncal and peripheral fat, assessed by skinfold thickness, and parental history of diabetes among subjects without diabetes in this urban South Indian population.

Adipose tissue metabolic and inflammatory responses to a mixed meal in lean, overweight and obese men

PURPOSE

Most of what we know about adipose tissue is restricted to observations derived after an overnight fast. However, humans spend the majority of waking hours in a postprandial (fed) state, and it is unclear whether increasing adiposity impacts adipose tissue responses to feeding. The aim of this research was to investigate postprandial responses in adipose tissue across varying degrees of adiposity.

METHODS

Thirty males aged 35-55 years with waist circumference 81-118 cm were divided equally into groups categorized as either lean, overweight or obese. Participants consumed a meal and insulinaemic, glycaemic and lipidaemic responses were monitored over 6 h. Subcutaneous adipose tissue samples were obtained at baseline and after 6 h to examine changes in gene expression and adipose tissue secretion of various adipokines.

RESULTS

Following consumption of the meal, insulin and glucose responses were higher with increased adiposity (total AUC effects of group; p = 0.058 and p = 0.027, respectively). At 6 h, significant time effects reflected increases in IL-6 (F = 14.7, p = 0.001) and MCP-1 (F = 10.7, p = 0.003) and reduction in IRS2 adipose tissue gene expression (F = 24.6, p < 0.001), all independent of adiposity. Ex vivo adipokine secretion from adipose tissue explants remained largely unchanged after feeding.

CONCLUSIONS

Increased systemic measures of postprandial metabolism with greater adiposity do not translate into increased inflammatory responses within adipose tissue. Instead, postprandial adipose tissue changes may represent a normal response to feeding or a (relatively) normalized response with increased adiposity due to either similar net exposure (i.e. per g of adipose) or reduced adipose tissue responsiveness.

Multidimensional individualised Physical ACTivity (Mi-PACT)--a technology-enabled intervention to promote physical activity in primary care: study protocol for a randomised controlled trial

BACKGROUND

Low physical activity is a major public health problem. New cost-effective approaches that stimulate meaningful long-term changes in physical activity are required, especially within primary care settings. It is becoming clear that there are various dimensions to physical activity with independent health benefits. Advances in technology mean that it is now possible to generate multidimensional physical activity 'profiles' that provide a more complete representation of physical activity and offer a variety of options that can be tailored to the individual. Mi-PACT is a randomised controlled trial designed to examine whether personalised multidimensional physical activity feedback and self-monitoring alongside trainer-supportive sessions increases physical activity and improves health outcomes in at-risk men and women.

METHODS/DESIGN

We aim to recruit 216 patients from within primary care aged 40 to 70 years and at medium or high risk of cardiovascular disease and/or type II diabetes mellitus. Adopting an unequal allocation ratio (intervention: control) of 2:1, participants will be randomised to one of two groups, usual care or the intervention. The control group will receive usual care from their general practitioner (GP) and standardised messages about physical activity for health. The intervention group will receive physical activity monitors and access to a web-based platform for a 3-month period to enable self-monitoring and the provision of personalised feedback regarding the multidimensional nature of physical activity. In addition, this technology-enabled feedback will be discussed with participants on 5 occasions during supportive one-to-one coaching sessions across the 3-month intervention. The primary outcome measure is physical activity, which will be directly assessed using activity monitors for a 7-day period at baseline, post intervention and at 12 months. Secondary measures (at these time-points) include weight loss, fat mass, and markers of metabolic control, motivation and well-being.

DISCUSSION

Results from this study will provide insight into the effects of integrated physical activity profiling and self-monitoring combined with in-person support on physical activity and health outcomes in patients at risk of future chronic disease.

TRIAL REGISTRATION

ISRCTN18008011 Trial registration date: 31 July 2013.

Does Visceral Fat Estimated by Dual-Energy X-ray Absorptiometry Independently Predict Cardiometabolic Risks in Adults?

BACKGROUND

Abdominal visceral fat, typically measured by computer tomography (CT) or magnetic resonance imaging (MRI), has been shown to correlate with cardiometabolic risks. The purpose of this study was to examine whether a newly developed and validated visceral fat measurement from dual-energy X-ray absorptiometry (DXA) provides added predictive value to the cross-sectional differences of cardiometabolic parameters beyond the traditional anthropometric and DXA adiposity parameters.

METHOD

A heterogeneous cohort of 194 adults (81 males and 113 females) with a BMI of 19 to 54 kg/m(2) participated in this cross-sectional study. Body composition was measured with a DXA densitometer. Visceral fat was then computed with a proprietary algorithm. Insulin sensitivity index (SI, measured by intravenous glucose tolerance test), blood pressures, and lipid profiles, and peak oxygen uptake were also measured as cardiometabolic risk parameters.

RESULTS

DXA-estimated visceral fat mass was associated with HDL cholesterol (regression coefficient [β] = -5.15, P < .01, adjusted R(2) = .21), triglyceride (β = 26.01, P < .01, adjusted R(2) = .14), and peak oxygen uptake (β = -3.15, P < .01, adjusted R(2) = .57) after adjusting for age, gender, and ethnicity. A subanalysis stratifying gender-specific BMI tertiles showed visceral fat, together with ethnicity, was independently associated with SI in overweight men and moderately obese women (second tertile).

CONCLUSIONS

Without requiring additional CT or MRI-based measurements, visceral fat detected by DXA might offer certain advantages over the traditional DXA adiposity parameters as means of assessing cardiometabolic risks.

Association of body fat composition and obstructive sleep apnea in the elderly: A longitudinal study

OBJECTIVE

Obesity and aging are considered risk factors for developing sleep apnea syndrome (OSA). The aim of this study was to determine the association between body fat composition and OSA in healthy elderly subjects examined in a 7-year longitudinal study.

METHODS

A total of 209 elderly with unrecognized OSA aged 68.3 ± 0.8 years underwent a clinical, ambulatory nocturnal respiratory recording, and anthropometric as well as body fat composition assessment by dual-energy X-ray absorptiometry (DEXA) at baseline and follow-up.

RESULTS

At study entry, 50.3% of the population showed an apnea+hypopnea index (AHI) <15 with a mean AHI of 16.8 ± 11. At follow-up, a reduction of OSA cases (42%) was evident with a mean AHI of 14.6 ± 10.2. The DEXA data demonstrated that body mass and total lean mass were reduced at follow-up, while central and peripheral fat mass showed a slight increase. Correlation analysis between the changes in DEXA measurements versus the changes in AHI and the indices of nocturnal hypoxemia showed an absence of a statistical correlation.

CONCLUSIONS

The lack of correlation between the DEXA measurement changes and the changes in the AHI confirm our previous data on the absence of a central fat mass effect on OSA in the elderly.

Relationship between body composition parameters and metabolic syndrome in young Thai adults

OBJECTIVE

The aim of this study was to evaluate the relationship between body composition parameters, i.e. waist circumference, android fat mass (AFM), gynoid fat mass (GFM), android to gynoid fat mass ratio (AG ratio) and metabolic syndrome (MS) risk components in young Thai adults.

METHODS

This was a cross-sectional study conducted among 391 adolescents (174 male, 217 female). The body mass index (BMI), waist circumference, blood pressure, triglyceride, high-density lipoprotein (HDL) cholesterol and glucose levels were determined. AFM, GFM and AG ratio were assessed by dual-energy X-ray absorptiometry (DXA). Linear regression analysis was done to assess the relationship of waist circumference, AFM, GFM and AG ratio with MS risk components' score, separately.

RESULTS

Among 391 young adults aged 18.5-21.8 years, MS was found in 5.9%. Participants with MS (n=23) had a significantly higher weight, height and BMI than those without MS. There was no statistically significant difference in bone mineral density between the two groups. At univariable linear regression analysis, waist circumferences, AFM, GFM and AG ratio showed significant relationship with MS risk components' score. However, after adjusting for gender, birth weight and BMI, AG ratio demonstrated greater relationship with MS risk components' score (β 1.89, 95%CI 1.096-2.978) than waist circumference (β 0.046, 95%CI 0.033-0.058) and AFM (β 0.979, 95%CI 0.667-1.290). No significant association was observed between GFM and MS risk components' score (β 0.077, 95%CI -0.089-0.243).

CONCLUSION

The results from this study indicated that AG ratio is a stronger predictor of MS than waist circumference and AFM in young Thai adults. The role of AG ratio for the diagnosis of MS needs to be further investigated.

The impact of adiposity on adipose tissue-resident lymphocyte activation in humans

Background/objectives:

The presence of T lymphocytes in human adipose tissue has only recently been demonstrated and relatively little is known of their potential relevance in the development of obesity-related diseases. We aimed to further characterise these cells and in particular to investigate how they interact with modestly increased levels of adiposity typical of common overweight and obesity.

Subjects/methods:

Subcutaneous adipose tissue and fasting blood samples were obtained from healthy males aged 35–55 years with waist circumferences in lean (<94 cm), overweight (94–102 cm) and obese (>102 cm) categories. Adipose tissue-resident CD4+ and CD8+ T lymphocytes together with macrophages were identified by gene expression and flow cytometry. T lymphocytes were further characterised by their expression of activation markers CD25 and CD69. Adipose tissue inflammation was investigated using gene expression analysis and tissue culture.

Results:

Participants reflected a range of adiposity from lean to class I obesity. Expression of CD4 (T-helper cells) and CD68 (macrophage), as well as FOXP3 RNA transcripts, was elevated in subcutaneous adipose tissue with increased levels of adiposity (P<0.001, P<0.001 and P=0.018, respectively). Flow cytometry revealed significant correlations between waist circumference and levels of CD25 and CD69 expression per cell on activated adipose tissue-resident CD4+ and CD8+ T lymphocytes (P-values ranging from 0.053 to <0.001). No such relationships were found with blood T lymphocytes. This increased T lymphocyte activation was related to increased expression and secretion of various pro- and anti-inflammatory cytokines from subcutaneous whole adipose tissue explants.

Conclusions:

This is the first study to demonstrate that even modest levels of overweight/obesity elicit modifications in adipose tissue immune function. Our results underscore the importance of T lymphocytes during adipose tissue expansion, and the presence of potential compensatory mechanisms that may work to counteract adipose tissue inflammation, possibly through an increased number of T-regulatory cells.

Association between Appendicular Fat Mass and Metabolic Risk Factors

BACKGROUND

Different regional fat depots have different effects on lipid and glucose metabolism. The purpose of this study is to examine the relationship between body fat distribution as measured by dual-energy X-ray absorptiometry (DEXA) and metabolic risk factors and to disclose whether there is any difference between groups with and without metabolic syndrome (MS).

METHODS

A total of 292 participants (98 men, 194 women) over 19 years old underwent whole-body DEXA to evaluate body composition with respect to the whole body, leg, arm, and android regions. Anthropometry and blood tests for metabolic risks were measured.

RESULTS

One hundred and seven participants were diagnosed with MS. The MS group had significantly higher android fat (%) and had lower leg fat (%), arm fat (%), and appendicular (arms + legs) fat (%) than the non-MS group. Android fat (%) had a positive correlation with waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), glucose, log insulin, hemoglobin A1c (HbA1c), triglyceride (TG), and low density lipoprotein cholesterol, and had a negative correlation with high density lipoprotein (HDL) cholesterol. Appendicular fat (%) had a negative correlation with WC, SBP, DBP, glucose, log insulin, HbA1c, and TG, and had a positive correlation with HDL cholesterol. The association of appendicular fat with metabolic risk was consistently observed in non-MS, but the association was not observed except for SBP, glucose and log insulin in MS.

CONCLUSION

In contrast with the adverse effects of android fat, appendicular fat distribution was associated with decreased risks of MS. The protective effect of appendicular fat against metabolic risk factors in non-MS was less characteristic in MS.

Association of serum tumor necrosis factor-related apoptosis inducing ligand with body fat distribution as assessed by dual X-rays absorptiometry

A low chronic inflammation mediated by cytokine release is considered a major pathogenic mechanism accounting for the higher risk of cardiovascular disease in the overweight/obese population. In this context, although the existence of a possible interaction between soluble tumor necrosis factor- (TNF-) related apoptosis inducing ligand (TRAIL) and quantity and localization, of adiposity in the body has been hypothesized, no studies have yet investigated this link by radiologic techniques able to assess directly fat mass (FM) in different body regions. To address this issue, we assessed body fat distribution by dual X-rays absorptiometry (DXA) in a sample of 103 women and investigated the possible association between the derived adiposity measures and serum TRAIL concentration. The level of TRAIL showed a positive and independent correlation with arms FM (P < 0.05), trunk FM (P < 0.001) and trunk FM% (P < 0.05), total FM and total FM% (P < 0.001 for both), and an inverse association with legs FM% (P < 0.05). Only trunk FM retained a significant correlation (P < 0.05) with TRAIL after adjusting for all the other indices of regional adiposity. In conclusion, from our study it emerged a significant and independent association of serum TRAIL levels with overall, and, mainly, central adiposity. Further studies are needed to longitudinally investigate the cause-effect relationship between change in body fat distribution and TRAIL.

BMI, RQ, diabetes, and sex affect the relationships between amino acids and clamp measures of insulin action in humans

Previous studies have used indirect measures of insulin sensitivity to link circulating amino acids with insulin resistance and identify potential biomarkers of diabetes risk. Using direct measures (i.e., hyperinsulinemic-euglycemic clamps), we examined the relationships between the metabolomic amino acid profile and insulin action (i.e., glucose disposal rate [GDR]). Relationships between GDR and serum amino acids were determined among insulin-sensitive, insulin-resistant, and type 2 diabetic (T2DM) individuals. In all subjects, glycine (Gly) had the strongest correlation with GDR (positive association), followed by leucine/isoleucine (Leu/Ile) (negative association). These relationships were dramatically influenced by BMI, the resting respiratory quotient (RQ), T2DM, and sex. Gly had a strong positive correlation with GDR regardless of BMI, RQ, or sex but became nonsignificant in T2DM. In contrast, Leu/Ile was negatively associated with GDR in nonobese and T2DM subjects. Increased resting fat metabolism (i.e., low RQ) and obesity were observed to independently promote and negate the association between Leu/Ile and insulin resistance, respectively. Additionally, the relationship between Leu/Ile and GDR was magnified in T2DM males. Future studies are needed to determine whether Gly has a mechanistic role in glucose homeostasis and whether dietary Gly enrichment may be an effective intervention in diseases characterized by insulin resistance.

Regional fat distribution and cardiometabolic risk in healthy postmenopausal women

BACKGROUND

Regional fat distribution is an important determinant of cardiometabolic risk after menopause. The aim of the present study was to investigate the association between indices of fat distribution obtained by Dual-energy X-ray Absorptiometry (DXA) and representative cardiometabolic risk factors in a cohort of healthy postmenopausal women.

METHODS

In this cross-sectional study, cardiometabolic risk factors were correlated with a variety of central and peripheral fat depots obtained by DXA, in a total of 150 postmenopausal women, free of diabetes and cardiovascular disease (age 54 ± 7 years, BMI 29.6 ± 5.8 kg/m(2), mean ± 1 SD).

RESULTS

After adjusting for age and total adiposity, DXA-derived indices of central and peripheral fat distribution displayed opposite associations (positive versus negative) with the examined cardiometabolic risk factors. In multivariate regression analysis, thoracic fat mass % was an independent predictor of blood pressure, HOMA index and triglycerides, abdominal fat mass % was an independent predictor of high sensitivity C-reactive protein, and abdominal-to-gluteofemoral fat ratio was an independent predictor of high density lipoprotein cholesterol. An index of peripheral fat distribution, gluteofemoral fat mass %, proved to be the most important determinant of metabolic syndrome (Odds Ratio 0.76, 95% confidence intervals 0.67-0.87, p<0.001), independent of total and central adiposity.

CONCLUSION

DXA-derived indices of regional fat distribution such as thoracic, abdominal and gluteofemoral fat, correlate significantly with cardiometabolic risk factors in healthy postmenopausal women, and may serve as clinically useful tools for evaluating cardiometabolic risk after menopause.

Adiposity and insulin resistance in humans: the role of the different tissue and cellular lipid depots

Human adiposity has long been associated with insulin resistance and increased cardiovascular risk, and abdominal adiposity is considered particularly adverse. Intra-abdominal fat is associated with insulin resistance, possibly mediated by greater lipolytic activity, lower adiponectin levels, resistance to leptin, and increased inflammatory cytokines, although the latter contribution is less clear. Liver lipid is also closely associated with, and likely to be an important contributor to, insulin resistance, but it may also be in part the consequence of the lipogenic pathway of insulin action being up-regulated by hyperinsulinemia and unimpaired signaling. Again, intramyocellular triglyceride is associated with muscle insulin resistance, but anomalies include higher intramyocellular triglyceride in insulin-sensitive athletes and women (vs men). Such issues could be explained if the "culprits" were active lipid moieties such as diacylglycerol and ceramide species, dependent more on lipid metabolism and partitioning than triglyceride amount. Subcutaneous fat, especially gluteofemoral, appears metabolically protective, illustrated by insulin resistance and dyslipidemia in patients with lipodystrophy. However, some studies suggest that deep sc abdominal fat may have adverse properties. Pericardial and perivascular fat relate to atheromatous disease, but not clearly to insulin resistance. There has been recent interest in recognizable brown adipose tissue in adult humans and its possible augmentation by a hormone, irisin, from exercising muscle. Brown adipose tissue is metabolically active, oxidizes fatty acids, and generates heat but, because of its small and variable quantities, its metabolic importance in humans under usual living conditions is still unclear. Further understanding of specific roles of different lipid depots may help new approaches to control obesity and its metabolic sequelae.

Body composition parameters in healthy Brazilian women differ from white, black, and Hispanic American women reference range

Body composition (BC) seems to vary between populations, suggesting the need for regional reference data. The objective of this study was to determine BC in Brazilian women. Five hundred healthy non-black Brazilian women aged 20 yr or older were included. Women with fractures, chronic diseases, medications affecting bone and mineral metabolism, coronary heart disease, pregnancy, silicone prosthesis, and Asians or Indians were excluded. BC by dual-energy X-ray absorptiometry (DXA) included total lean mass, appendicular lean mass, skeletal muscle index, and total body fat (BF). Reference values were made for 10-yr age groups. Lean mass decreased with age reaching the lowest values in women aged 80 yr and older. BF showed a bimodal distribution: increased with age until 50-59 yr, with a slight subsequent decrease. BF in Brazilian women did not differ from American women, except in the age groups 75-79 and 80-84 yr, where BF was lower (p < 0.05). Fat mass index was consistently higher between African and Hispanic American women (p < 0.05). Lean mass was consistently lower in Brazilian women compared with Americans in almost all age and ethnic groups (p < 0.05). BC in Brazilian women differs from American reference data. Our findings support the notion that BC varies according to ethnicity.

Relation of central fat mass to obstructive sleep apnea in the elderly

STUDY OBJECTIVES

Obesity is a recognized risk factor for obstructive sleep apnea syndrome (OSAS). We evaluated whether total trunk and central fat mass (CFM) is associated with OSAS in elderly subjects.

DESIGN

Cross-sectional.

SETTING

Body composition assessment by dual-energy X-ray absorbsiometry (DEXA).

PARTICIPANTS

749 volunteers aged 67.2 ± 0.8 years (59.4% women).

INTERVENTION

All participants underwent evaluation of their body composition by DEXA in parallel with clinical and polygraphic assessments. The presence of OSAS was defined by an apnea plus hypopnea index (AHI) ≥ 15.

MEASUREMENTS AND RESULTS

A total of 44.8% of the population had an AHI < 15, and 55.2% presented OSAS. OSAS subjects were more frequently overweight and had a higher total trunk fat mass and central fat mass (CFM). Correlation analyses revealed that body mass index (r = 0.27, P < 0.001), neck circumference (r = 0.35, P < 0.001), and CFM (r = 0.23, P < 0.001) were significantly related to AHI. Logistic regression analysis indicated that in mild OSAS cases (> 15AHI < 30), BMI (OR: 1.10; 95% CI: 1.03-1.18; P = 0.008), and male gender (OR: 1.49; 95% CI: 1.05-2.12, P = 0.03) were key factors explaining an AHI between 15 and 30. In severe cases (AHI > 30), male gender (OR: 3.65; 95% CI: 2.40-5.55; P < 0.001) and CFM (OR: 1.10; 95% CI: 1.03-1.19; P = 0.009) were significant independent predictors of OSAS.

CLINICAL TRIAL REGISTRATION

NCT 00759304 and NCT 00766584.

CONCLUSIONS

Although central fat mass plays a role in the occurrence of severe OSAS in men older than 65 years of age, its low discriminative sensitivity in mild OSAS cases does not warrant systematic use of DEXA for the diagnosis of OSAS.

Associations of leg fat accumulation with adiposity-related biological factors and risk of metabolic syndrome

OBJECTIVE

To examine associations between regional fat mass (FM) distribution and cardiometabolic risk factors among ethnic minority groups, such as non-Hispanic blacks and Hispanics.

DESIGN AND METHODS

The associations among 8,802 US residents who participated in the 1999-2004 US National Health and Nutrition Examination Survey were examined. Body composition was measured using dual-energy X-ray absorptiometry. Leg fat indices included leg FM, leg FM percent (FM%), leg to whole body FM ratio (leg/whole), and leg to trunk FM ratio (leg/trunk). The correlation between leg fat indices and adiposity-related risk factors, as well as the association of these indices with metabolic syndrome (MetS) was evaluated.

RESULTS

After adjusting for covariates including age, gender, and trunk FM or trunk FM%, higher leg FM and leg FM% were, in general, correlated favorably with adiposity-related risk factors and associated with lower odds of MetS in all ethnicities, including non-Hispanic whites and blacks and Hispanic groups. In addition, in all multivariate-adjusted models, leg/whole and leg/trunk ratios were strongly associated with lower levels of most risk factors and decreased odds of MetS in these ethnicities (all odds ratios comparing extreme quintiles < 0.1).

CONCLUSIONS

Results show that leg fat accumulation is inversely associated with adiposity-related biological factors and risk of MetS in both whites and ethnic groups, suggesting that regional fat distribution plays an important role in the etiology of adiposity-related diseases in these populations.

High dietary magnesium intake is associated with low insulin resistance in the Newfoundland population

Background

Magnesium plays a role in glucose and insulin homeostasis and evidence suggests that magnesium intake is associated with insulin resistance (IR). However, data is inconsistent and most studies have not adequately controlled for critical confounding factors.

Objective

The study investigated the association between magnesium intake and IR in normal-weight (NW), overweight (OW) and obese (OB) along with pre- and post- menopausal women.

Design

A total of 2295 subjects (590 men and 1705 women) were recruited from the CODING study. Dietary magnesium intake was computed from the Willett Food Frequency Questionnaire (FFQ). Adiposity (NW, OW and OB) was classified by body fat percentage (%BF) measured by Dual-energy X-ray absorptiometry according to the Bray criteria. Multiple regression analyses were used to test adiposity-specific associations of dietary magnesium intake on insulin resistance adjusting for caloric intake, physical activity, medication use and menopausal status.

Results

Subjects with the highest intakes of dietary magnesium had the lowest levels of circulating insulin, HOMA-IR, and HOMA-ß and subjects with the lowest intake of dietary magnesium had the highest levels of these measures, suggesting a dose effect. Multiple regression analysis revealed a strong inverse association between dietary magnesium with IR. In addition, adiposity and menopausal status were found to be critical factors revealing that the association between dietary magnesium and IR was stronger in OW and OB along with Pre-menopausal women.

Conclusion

The results of this study indicate that higher dietary magnesium intake is strongly associated with the attenuation of insulin resistance and is more beneficial for overweight and obese individuals in the general population and pre-menopausal women. Moreover, the inverse correlation between insulin resistance and dietary magnesium intake is stronger when adjusting for %BF than BMI.

Hepatic steatosis in human immunodeficiency virus: a prospective study in patients without viral hepatitis, diabetes, or alcohol abuse

BACKGROUND AND AIMS

Abnormal liver enzymes (LEs) are common in those infected with human immunodeficiency virus (HIV). Histologic data on those with abnormal LE without viral hepatitis are lacking.

METHODS

HIV-positive subjects without hepatitis C virus, hepatitis B virus, alcohol abuse, and diabetes mellitus with more than 1 abnormal LE, defined as 1.25 ULN in aspartate aminotransferase, alanine aminotransferase, or alkaline phosphatase, over 6 months were included. Subjects underwent a 2-hour oral glucose tolerance test, fasting lipids, insulin and glucose for insulin resistance (IR) by homeostasis model assessment for insulin resistance (HOMA-IR) and dual-energy X-ray absorptiometry for fat distribution. Biopsies were read blindly to clinical data, and scored by Ishak histologic activity index for inflammation and fibrosis and NAFLD activity score.

RESULTS

Fourteen patients underwent biopsy. All were on highly active antiretroviral therapy with undetectable HIV RNA and mean CD4 614. The histologic activity index scores for inflammation and fibrosis were 3.43(1.4) and 1.71(1.26), respectively, and 2 patients had advanced fibrosis (bridging fibrosis/cirrhosis). The majority (65%) of patients had steatosis: grade 1: 21%, grade 2: 28%, and grade 3: 14%. Hepatocyte ballooning was seen in 7 (40%) but nonalcoholic steatohepatitis (NASH) was diagnosed only in 4 (26%). NAFLD activity score of all biopsies of 3.07 (2.2; range, 0 to 5). HOMA-IR was higher in those with compared with those without steatosis (3.52 vs. 1.91; P = 0.11) and highest in those with NASH (4.89). Using multivariate logistic regression, only increased γ-glutamyl transpeptidase (P = 0.0009) predicted steatosis whereas HOMA-IR (P = 0.0046) predicted NASH.

CONCLUSIONS

Although steatosis is common in HIV patients with abnormal LE without diabetes mellitus, alcohol, or viral hepatitis coinfection, NASH was observed in only 26%. The only clinical or laboratory feature associated with biopsy proven steatosis and NASH were γ-glutamyl transpeptidase and a calculated measure of insulin resistance, respectively. Further studies are needed in this population to determine the long-term clinical significance.

Validation of dual energy X-ray absorptiometry measures of abdominal fat by comparison with magnetic resonance imaging in an Indian population

Objective

Abdominal adiposity is an important risk factor for diabetes and cardiovascular disease in Indians. Dual energy X-ray absorptiometry (DXA) can be used to determine abdominal fat depots, being more accessible and less costly than gold standard measures such as magnetic resonance imaging (MRI). DXA has not been fully validated for use in South Asians. Here, we determined the accuracy of DXA for measurement of abdominal fat in an Indian population by comparison with MRI.

Design

146 males and females (age range 18–74, BMI range 15–46 kg/m²) from Hyderabad, India underwent whole body DXA scans on a Hologic Discovery A scanner, from which fat mass in two abdominal regions was calculated, from the L1 to L4 vertebrae (L1L4) and from the L2 to L4 vertebrae (L2L4). Abdominal MRI scans (axial T1-weighted spin echo images) were taken, from which adipose tissue volumes were calculated for the same regions.

Results

Intra-class correlation coefficients between DXA and MRI measures of abdominal fat were high (0.98 for both regions). Although at the level of the individual, differences between DXA and MRI could be large (95% of DXA measures were between 0.8 and 1.4 times MRI measures), at the sample level, DXA only slightly overestimated MRI measures of abdominal fat mass (mean difference in L1L4 region: 2% (95% CI:0%, 5%), mean difference in L2L4 region:4% (95% CI: 1%, 7%)). There was evidence of a proportional bias in the association between DXA and MRI (correlation between difference and mean −0.3), with overestimation by DXA greater in individuals with less abdominal fat (mean bias in leaner half of sample was 6% for L1L4 (95%CI: 2, 11%) and 7% for L2L4 (95% CI:3,12%).

Conclusions

DXA measures of abdominal fat are suitable for use in Indian populations and provide a good indication of abdominal adiposity at the population level.

Evidence for the association between abdominal fat and cardiovascular risk factors in overweight and obese African American women

OBJECTIVE

To determine the association between total body fat and abdominal region fat derived from dual-energy x-ray absorptiometry (DXA) scans and cardiovascular disease (CVD) risk factors in middle- to older-aged African American (AA) women. We also compared tape-measured waist and hip circumference and their ratio (WHR) with DXA measurements in the context of CVD risk factor predictability.

METHODS

Participants included 59 overweight or obese African American women (age, 48.7 ± 5.6 years). Anthropometries, including waist and hip circumferences, were measured, and DXA scans were used to derive fat mass from the total body and abdominal region. Blood analyses included glucose, total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol/HDL and LDL/HDL ratios, C-reactive protein (CRP), and fibrinogen. Multiple linear regression models were used to investigate the association among DXA-derived fat mass measures, waist circumference, WHR, and cardiovascular risk factors.

RESULTS

Among DXA-derived fat mass measures, DXA-derived abdominal fat mass showed the best prediction for glucose and triglycerides, although waist circumference and DXA-derived abdominal fat mass had equivalent capacity for predicting the total cholesterol/HDL ratio. Furthermore, waist circumference showed the best prediction for LDL/HDL ratio and CRP.

CONCLUSIONS

Both DXA-derived abdominal fat mass and waist circumference had comparable capacity for predicting blood lipid profiles and CRP. Therefore, if waist circumference is measured correctly, it could be used as the simplest means of predicting CVD risk factors in overweight/obese AA women when DXA is not available.

Neuroadrenergic dysfunction along the diabetes continuum: a comparative study in obese metabolic syndrome subjects

Neuroadrenergic function in type 2 diabetic (T2D) patients without neuropathy is poorly characterized. We therefore compared sympathetic nervous system activity at rest and during an oral glucose tolerance test in obese metabolic syndrome (MetS) subjects classified as glucose intolerant (impaired glucose tolerance [IGT]; n = 17) or treatment-naive T2D (n = 17). Untreated subjects, matched for age (mean 59 ± 1 year), sex, BMI (32.4 ± 0.6 kg/m(2)), and family history of diabetes were studied. We measured resting muscle sympathetic nerve activity (MSNA) by microneurography, whole-body norepinephrine kinetics by isotope dilution, insulin sensitivity by euglycemic-hyperinsulinemic clamp (steady-state glucose utilization adjusted for fat-free mass and steady-state insulin concentration [M/I]), and MetS components. T2D subjects had higher resting MSNA burst incidence (67 ± 4 versus 55 ± 3 bursts per 100 heartbeats; P = 0.05) and arterial norepinephrine levels (264 ± 33 versus 167 ± 16 pg/mL; P = 0.02), lower plasma norepinephrine clearance (by 17%; P = 0.03), and reduced neuronal reuptake compared with IGT subjects (by 46%; P = 0.04). Moreover, norepinephrine spillover responses to glucose ingestion were blunted in T2D subjects. The M/I value independently predicted whole-body norepinephrine spillover (r = -0.47; P = 0.008), whereas fasting insulin level related to neuronal norepinephrine reuptake (r = -0.35, P = 0.047). These findings demonstrate that progression to T2D is associated with increased central sympathetic drive, blunted sympathetic responsiveness, and altered norepinephrine disposition.

The limited screening value of insulin-like growth factor-I as a marker for alterations in body composition in very long-term adult survivors of childhood cancer

BACKGROUND

The clinical relevance of low IGF-I levels, caused by cranial radiotherapy, in adult childhood cancer survivors has not been studied extensively. We evaluated whether IGF-I is a useful marker for altered body composition and growth hormone deficiency (GHD) in this group.

PROCEDURE

We analyzed retrospective data from 610 adult childhood cancer survivors, retrieved from the late effects clinic. Median age at diagnosis was 6 years (interquartile range 3-11) and follow-up time was 18 years (13-24). We assessed IGF-I standard deviation scores (SDS), anthropometrical measures, growth hormone stimulation tests in patients with clinical signs of GHD, and measures of body composition (assessed by dual X-ray absorptiometry, Lunar Prodigy).

RESULTS

In 58 cranially irradiated acute leukemia survivors (25 Gy (24-25)) and 56 locally irradiated brain tumor survivors (42 Gy (35-54)) we found significantly lower IGF-I SDS (P < 0.001), lower height SDS (P < 0.001), higher body mass index (P = 0.01), higher waist-hip ratio (WHR; P = 0.001), higher total fat percentage SDS (P < 0.001), and lower lean body mass SDS (P < 0.001), as compared to 452 not cranially irradiated survivors. IGF-I showed a weak inverse correlation with BMI (r = -0.12, P = 0.04), WHR (r = -0.15, P = 0.01), total fat percentage (r = - 0.14, P = 0.02), and a positive correlation with lean body mass (r = 0.15, P = 0.01). In patients with low IGF-I levels, IGF-I did not significantly differ between subjects with and without GHD as determined by GH-stimulation testing (P = 0.39).

CONCLUSION

This study shows that IGF-I has limited value as a marker for alterations in body composition in adult childhood cancer survivors.

Obesity is underestimated using body mass index and waist-hip ratio in long-term adult survivors of childhood cancer

Objective

Obesity, represented by high body mass index (BMI), is a major complication after treatment for childhood cancer. However, it has been shown that high total fat percentage and low lean body mass are more reliable predictors of cardiovascular morbidity. In this study longitudinal changes of BMI and body composition, as well as the value of BMI and waist-hip ratio representing obesity, were evaluated in adult childhood cancer survivors.

Methods

Data from 410 survivors who had visited the late effects clinic twice were analyzed. Median follow-up time was 16 years (interquartile range 11–21) and time between visits was 3.2 years (2.9–3.6). BMI was measured and body composition was assessed by dual X-ray absorptiometry (DXA, Lunar Prodigy; available twice in 182 survivors). Data were compared with healthy Dutch references and calculated as standard deviation scores (SDS). BMI, waist-hip ratio and total fat percentage were evaluated cross-sectionally in 422 survivors, in who at least one DXA scan was assessed.

Results

BMI was significantly higher in women, without significant change over time. In men BMI changed significantly with time (ΔSDS = 0.19, P<0.001). Percentage fat was significantly higher than references in all survivors, with the highest SDS after cranial radiotherapy (CRT) (mean SDS 1.73 in men, 1.48 in women, P<0.001). Only in men, increase in total fat percentage was significantly higher than references (ΔSDS = 0.22, P<0.001). Using total fat percentage as the gold standard, 65% of female and 42% of male survivors were misclassified as non-obese using BMI. Misclassification of obesity using waist-hip ratio was 40% in women and 24% in men.

Conclusions

Sixteen years after treatment for childhood cancer, the increase in BMI and total fat percentage was significantly greater than expected, especially after CRT. This is important as we could show that obesity was grossly underestimated using BMI and waist-hip ratio.

Effects of losartan on whole body, skeletal muscle and vascular insulin responses in obesity/insulin resistance without hypertension

AIMS

Renin-angiotensin system antagonists have been found to improve glucose metabolism in obese hypertensive and type 2 diabetic subjects. The mechanism of these effects is not well understood. We hypothesized that the angiotensin receptor antagonist losartan would improve insulin-mediated vasodilation, and thereby improve insulin-stimulated glucose uptake in skeletal muscle of insulin-resistant subjects.

METHODS

We studied subjects with obesity and insulin resistance but without hypertension, hypercholesterolaemia or dysglycaemia [age 39.0 ± 9.6 yr (mean ± SD), body mass index (BMI) 33.2 ± 5.9 kg/m(2) , BP 115.8 ± 12.2/70.9 ± 7.2 mmHg, LDL 2.1 ± 0.5 mmol/l]. Subjects were randomized to 12 weeks' double-blind treatment with losartan 100 mg once daily (n = 9) or matching placebo (n = 8). Before and after treatment, under hyperinsulinaemic euglycaemic clamp conditions we measured whole-body insulin-stimulated glucose disposal, insulin-mediated vasodilation, and insulin-stimulated leg glucose uptake by the limb balance technique.

RESULTS

Whole-body insulin-stimulated glucose disposal was not significantly increased by losartan. Insulin-mediated vasodilation was augmented following both treatments [increase in leg vascular conductance: pretreatment 0.7 ± 0.3 l/min/mmHg (losartan, mean ± SEM) and 0.9 ± 0.3 (placebo), posttreatment 1.0 ± 0.4 (losartan) and 1.3 ± 0.6 (placebo)] but not different between treatment groups (p = 0.53). Insulin's action to augment nitric oxide (NO) production and to augment endothelium-dependent vasodilation was also not improved. Leg glucose uptake was not significantly changed by treatments, and not different between groups (p = 0.11).

CONCLUSIONS

These findings argue against the hypothesis that losartan might improve skeletal muscle glucose metabolism by improving insulin-mediated vasodilation in normotensive insulin-resistant obese subjects. The metabolic benefits of angiotensin receptor blockers may require the presence of hypertension in addition to obesity-associated insulin resistance.

The effects of dietary weight loss with or without exercise training on liver enzymes in obese metabolic syndrome subjects

AIM

Insulin resistance and visceral adiposity are predisposing factors for fatty liver disease. The main objectives of this study were (i) to compare the effects of caloric restriction (CR) alone or together with moderate-intensity aerobic exercise training (CR+EX) on liver enzymes, a surrogate marker of liver injury, in obese metabolic syndrome (MetS) subjects and (ii) to identify anthropometric, metabolic, cardiovascular and dietary predictors of changes in liver enzymes.

METHODS

Sedentary men and women (n = 63), aged 55 ± 6 (s.d.) years with body mass index 32.7 ± 4.1 kg/m(2) and confirmed MetS, were randomized to 12-week CR, CR+EX or no treatment (Control).

RESULTS

Weight loss averaged 7.6% in the CR and 9.1% in the CR+EX group (time effect, p < 0.001; group effect, p = 0.11); insulin sensitivity improved by 49 and 45%, respectively (both p < 0.001). Fitness (maximal oxygen consumption) increased by 19% in the CR+EX group only (p < 0.001). Alanine aminotransferase (ALT) levels decreased by 20% in the CR and 24% in the CR+EX group (time effect, both p < 0.001; group effect, p = 0.68); corresponding values for γ-glutamyltransferase (GGT) were -28 and -33%, respectively (time effect, both p < 0.001; group effect, p = 0.28). Reduction in abdominal fat mass (measured by DXA from L1 to L4) independently predicted ΔALT (r = 0.42, p = 0.005) and ΔGGT (r = 0.55, p < 0.001), whereas change in dietary saturated fat intake was independently associated with ΔALT (r = 0.35, p = 0.03).

CONCLUSIONS

Reductions in central adiposity and saturated fat intake are key drivers of improvement in liver enzymes during lifestyle interventions. Exercise training did not confer significant incremental benefits in this study.

Lower extremity fat mass is associated with insulin resistance in overweight and obese individuals: the CARDIA study

Lower extremity fat mass (LEFM) has been shown to be favorably associated with glucose metabolism. However, it is not clear whether this relationship is similar across varying levels of obesity. We hypothesized that lower amounts of LEFM is associated with higher insulin resistance (IR) and this association may vary according to weight status. Participants with available measures were examined from the Coronary Artery Risk Development in Young Adults study (CARDIA), a multi-center longitudinal study of the etiology of atherosclerosis in black and white men and women aged 38-50 years old in 2005-2006 (n = 1,579). The homeostasis model assessment of IR (HOMA(IR)) was calculated to estimate IR, regional adiposity was measured using dual energy X-ray absorptiometry (DXA), and weight status was defined according to BMI categories. Obese and overweight participants exhibited higher IR, total fat mass (FM), trunk FM (TFM), and LEFM compared to normal weight participants. After controlling for age, height, race, study center, education, smoking, and cardiorespiratory fitness (CRF), greater LEFM was significantly associated with higher IR only in normal weight men and women. Further adjustment for TFM revealed that lower LEFM was significantly associated with higher IR in overweight and obese men and women and the positive association in normal weight individuals was attenuated. These results suggest that excess adiposity in the lower extremities may attenuate the metabolic risk observed at a given level of abdominal adiposity in overweight and obese individuals. Weight status presents additional complexity since the metabolic influence of adipose tissue may not be homogenous across anatomic regions or level of obesity.

Association between insulin resistance and lean mass loss and fat mass gain in older men without diabetes mellitus

OBJECTIVES

To examine the associations between insulin resistance and changes in body composition in older men without diabetes mellitus.

DESIGN

Longitudinal cohort study of older men participating in the Osteoporotic Fractures in Men (MrOS) study.

SETTING

Six U.S. clinical centers.

PARTICIPANTS

Three thousand one hundred thirty-two ambulatory men aged 65 and older at baseline.

MEASUREMENTS

Baseline insulin resistance was calculated for men without diabetes mellitus using the homeostasis model assessment of insulin resistance (HOMA-IR). Total lean, appendicular lean, total fat, and truncal fat mass were measured using dual energy X-ray absorptiometry scans at baseline and 4.6 ± 0.3 years later in 3,132 men with HOMA-IR measurements.

RESULTS

There was greater loss of weight, total lean mass, and appendicular lean mass and less gain in total fat mass and truncal fat mass with increasing quartiles of HOMA-IR (P<.001 for trend). Insulin-resistant men in the highest quartile had higher odds of 5% or more loss of weight (odds ratio (OR)=1.88, 95% confidence interval (CI)=1.46-2.43), total lean mass (OR=2.09, 95% CI=1.60-2.73) and appendicular lean mass (OR=1.57, 95% CI=1.27-1.95) and lower odds of 5% or more gain in total fat mass (OR=0.56, 95% CI=0.45-0.68) and truncal fat mass (OR=0.52, 95% CI=0.42-0.64) than those in the lowest quartile. These findings remained significant after accounting for age, site, baseline weight, physical activity, and change in physical activity. These associations were also independent of other metabolic syndrome features and medications.

CONCLUSION

Greater lean mass loss and lower fat mass gain occurred in insulin-resistant men without diabetes mellitus than in insulin-sensitive men. Insulin resistance may accelerate age-related sarcopenia.