Neck circumference as a predictor of cardiometabolic risk and truncal obesity in people living with HIV

Introduction

Introduction: recent studies have suggested the use of neck circumference as a parameter capable of identifying risks of cardiometabolic complications and the accumulation of truncal fat caused by both antiretroviral therapy and the lifestyle of people with the human immunodeficiency virus (HIV). Objective: to investigate the relationship between neck circumference and anthropometric indicators and to assess cardiometabolic risk and truncal obesity through proposed cut-off points. Methods: cross-sectional study including 233 people with HIV. Demographic, socioeconomic, lifestyle and clinical data were collected using a structured questionnaire. The anthropometric evaluation included: weight, height, body mass index (BMI) measurements; waist (WC), neck (NC), arm and arm muscle circumferences; triceps and subscapular skinfolds and their sum. ROC curves were constructed to determine the accuracy of NC in predicting cardiometabolic risk in people living with HIV. Results: the sample was 57.5 % male, with a mean age of 38.4 years (95 %CI: 37.2-39.7 years). NC showed a positive and significant correlation with all anthropometric variables analyzed (p < 0.05), and a higher correlation strength with WC and BMI. The NC cut-off point selected as a predictor of risk of cardiac metabolic complications and truncal obesity in women was ≥ 32.4 cm, considering both WC and BMI. For men, the NC cut-off points were different when considering WC (≥ 39.6 cm) and BMI (≥ 38.1 cm) as a reference. It is worth noting that NC performed well in ROC curve analysis for men, while in women it was a poor performance. Conclusion: NC proved to be a promising indicator in the assessment of nutrition and health of people living with HIV, especially in men.

Impact of Roux-en-Y Gastric Bypass and Vertical Gastrectomy on weight loss: a retrospective and longitudinal study in the State of Paraná, Brazil

AIM

to compare the impact of Roux's Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG) techniques on body weight reduction over 1 and 5 years after bariatric surgery in obese patients in the state of Paraná.

METHODS

longitudinal and retrospective study, conducted between January 2010 and December 2013, with 737 patients of both sexes submitted to RYGB or SG and evaluated in the preoperative, 1 and 5 years after bariatric surgery (BS). Age, height, body weight, Body Mass Index (BMI), biochemical and pressure parameters were recorded.

RESULTS

of the total of patients, men represented lower frequency, were slightly older, with higher body weight, BMI and worse metabolic and pressure conditions than women in pre-BS (p<0.05). Regardless of sex, RYGB and SG were effective in promoting body weight reduction and BMI in 1 and 5 years after BS; the RYGB technique had greater impact on these variables in both sexes (p<0.05). The highest percentage of lost weight was observed in women who underwent the RYGB technique in the first year after BS. Five years after BS, the RYGB technique promoted a higher rate of body weight reduction in men and women compared to the SG technique (p<0.05).

CONCLUSION

regardless of sex, the RYGB technique promotes a higher degree of body weight reduction and BMI over time compared to the SG; having its biggest impacts in the 1 year after BS, especially in women.

O impacto do Bypass Gástrico em Y de Roux e da Gastrectomia Vertical na perda de peso: um estudo retrospectivo e longitudinal no Estado do Paraná, Brasil

RESUMO Objetivo: comparar o impacto das técnicas Bypass Gástrico em Y de Roux (BGYR) e Gastrectomia Vertical (GV) na redução do peso corporal ao longo de 1 e 5 anos após a cirurgia bariátrica em pacientes obesos no Estado do Paraná. Métodos: estudo longitudinal e retrospectivo, realizado entre janeiro de 2010 a dezembro de 2013, com 737 pacientes de ambos os sexos submetidos a BGYR ou GV e avaliados no pré-cirúrgico, 1 e 5 anos após Cirurgia Bariátrica (CB). Foram registrados idade, estatura, peso corporal, Índice de Massa Corpórea (IMC), parâmetros bioquímicos e pressóricos. Resultados: do total de pacientes, homens representavam menor frequência, eram ligeiramente mais velhos, com maior peso corporal, IMC e pior condição metabólica e pressórica que mulheres no pré-CB (p<0,05). Independente do sexo, BGYR e GV foram efetivas em promover redução do peso corporal e IMC em 1 e 5 anos pós-CB; tendo a técnica de BGYR maior impacto nestas variáveis em ambos os sexos (p<0,05). A maior porcentagem de peso perdido foi observada em mulheres submetidas a técnica da BGYR no primeiro ano após a CB. Cinco anos após a CB, a técnica de BGYR promoveu maior taxa de redução de peso corporal em homens e mulheres comparado a técnica da GV (p<0,05). Conclusão: independente do sexo a técnica de BGYR promove maior grau de redução do peso corporal e IMC ao longo do tempo em comparação com a GV; tendo seus maiores impactos no 1 ano pós-CB sobretudo em mulheres.

Non-linear Associations Between Visceral Adipose Tissue Distribution and Anthropometry-Based Estimates of Visceral Adiposity

Background

Recent evidence suggests that excess visceral adipose tissue (VAT) is associated with future loss of subcutaneous adipose tissue (SAT) and skeletal muscle (SM) with aging. In clinical settings (abdominal) circumferences are commonly used to estimate body composition (BC). We aimed to study the linearity of VAT distribution ratios (i.e., VAT/SAT ratio and VAT/SM ratio), waist-to-hip ratio (WHR) and waist circumference (WC) with age and the relationship of VAT distribution ratios with anthropometry (i.e., WHR and WC).

Materials and Methods

BC was determined using whole body magnetic resonance imaging in a large multi-ethnic group of 419 adults (42% white, 30% black, 15% Hispanic, 13% Asian, 1% other) with a BMI ranging from 15.9 to 40.8kg/m2. Linear and non-linear regression analysis was used to examine the linearity of VAT distribution ratios and anthropometry from 18 to 88 years. The relation between VAT distribution ratios and anthropometry was assessed separately.

Results

In both sexes non-linear relationships were found between BC estimates and age, and between BC measures mutually. The ratios of VAT/SAT and VAT/SM showed quadratic relationships with age. VAT distribution ratios showed exponential or quadratic relationships with anthropometry with coefficients of determination ranging between 18 and 55%.

Conclusion

In both sexes, VAT distribution ratios showed curvilinear relationships with age and with anthropometry. Given the sex differences in VAT distribution ratios, WHR and WC represent different BC proportions in men and women. These results emphasize the challenge when interpreting changes in BC based upon linear extrapolations in clinical practice.

Efficacy of a novel herbal formulation for weight loss demonstrated in a 16-week randomized, double-blind, placebo-controlled clinical trial with healthy overweight adults

AIM

To re-evaluate the weight loss efficacy of LI85008F in healthy overweight adults via a 16-week randomized, double-blind, placebo-controlled clinical study.

MATERIALS AND METHODS

One hundred and forty overweight participants (body mass index [BMI] 27-29.9 kg/m² , 29.3% male; ages 21-50 years) were randomized into placebo (n =70) and LI85008F (n =70) groups. The participants received either 900 mg/d of LI85008F in two divided doses or two identical placebo capsules. In addition, participants were counselled to follow an ~1800 kcal/d diet and to engage in walking for 30 min, 5 d/wk throughout the study.

RESULTS

At the end of the trial period, the LI85008F supplemented group showed significant reductions in body weight (5.36 ± 1.769 vs. 0.87 ± 1.381 kg; P < 0.0001) and BMI (2.05 ± 0.693 vs. 0.34 ± 0.559 kg/m² ; P < 0.0001), compared with placebo. Significant reductions in waist and hip circumferences, and a 2.08-fold reduction of waist/hip ratio, were noted in the LI85008F supplemented group. LI85008F supplementation also resulted in significant improvements in lipid profiles, compared with the placebo; low-density lipoprotein (LDL) cholesterol decreased, while high-density lipoprotein (HDL) cholesterol increased, resulting in a significantly improved LDL/HDL ratio. No major adverse events were reported by the participants during the study.

CONCLUSIONS

The unique herbal extract blend LI85008F, combined with modest calorie restriction and physical activity, is well tolerated, safe, and effective for weight management in overweight men and women.

Prevalence of 'obesity-associated gonadal dysfunction' in severely obese men and women and its resolution after bariatric surgery: a systematic review and meta-analysis

BACKGROUND

Sexual dimorphism manifests noticeably in obesity-associated gonadal dysfunction. In women, obesity is associated with androgen excess disorders, mostly the polycystic ovary syndrome (PCOS), whereas androgen deficiency is frequently present in obese men in what has been termed as male obesity-associated secondary hypogonadism (MOSH). Obesity-associated gonadal dysfunction, consisting of PCOS in women and MOSH in men, is a frequent finding in patients with severe obesity and it may be ameliorated or even resolve with marked weight loss, especially after bariatric surgery.

OBJECTIVE AND RATIONALE

We aimed to obtain an estimation of the prevalence of obesity-associated gonadal dysfunction among women and men presenting with severe obesity and to evaluate the response to bariatric surgery in terms of resolution and/or improvement of this condition and changes in circulating sex hormone concentrations.

SEARCH METHODS

We searched PubMed and EMBASE for articles published up to June 2016. After deleting duplicates, the abstract of 757 articles were analyzed. We subsequently excluded 712 articles leaving 45 studies for full-text assessment of eligibility. Of these, 16 articles were excluded. Hence, 29 studies were included in the quantitative synthesis and in the different meta-analyses. Quality of the studies was assessed using the Quality index for prevalence studies and the Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group available from the National Heart, Lung and Blood Institute. For meta-analyses including more than 10 studies, we used funnel and Doi plots to estimate publication bias.

OUTCOMES

In severely obese patients submitted to bariatric surgery, obesity-associated gonadal dysfunction was very prevalent: PCOS was present in 36% (95CI 22-50) of women and MOSH was present in 64% (95CI 50-77) of men. After bariatric surgery, resolution of PCOS was found in 96% (95CI 89-100) of affected women and resolution of MOSH occurred in 87% (95CI 76-95) of affected men. Sex hormone-binding globulin concentrations increased after bariatric surgery in women (22 pmol/l, 95CI 2-47) and in men (22 pmol/l, 95CI 19-26) and serum estradiol concentrations decreased in women (-104 pmol/l, 95CI -171 to -39) and to a lesser extent in men (-22 pmol/l, 95CI -38 to -7). On the contrary, sex-specific changes were observed in serum androgen concentrations: for example, total testosterone concentration increased in men (8.1 nmol/l, 95CI 6-11) but decreased in women (-0.7 nmol/l, 95CI -0.9 to -0.5). The latter was accompanied by resolution of hirsutism in 53% (95CI 29-76), and of menstrual dysfunction in 96% (95CI 88-100), of women showing these symptoms before surgery.

WIDER IMPLICATIONS

Obesity-associated gonadal dysfunction is among the most prevalent comorbidities in patients with severe obesity and should be ruled out routinely during their initial diagnostic workup. Considering the excellent response regarding both PCOS and MOSH, bariatric surgery should be offered to severely obese patients presenting with obesity-associated gonadal dysfunction.

Differential impacts of cardiac and abdominal ectopic fat deposits on cardiometabolic risk stratification

Background

Previous studies have shown that excessive abdominal visceral adipose tissue (AVAT) and epicardial adipose tissue (EAT) are risk factors of cardiometabolic disease; we hypothesized there is differential contribution of abdominal and cardiac fat deposits to the cardiometabolic profiles.

Methods

Two hundred eight consecutive subjects with clinical suspicion of coronary artery disease (CAD) who underwent cardiac and abdominal CT for Agatston score and abdominal visceral fat measurement were retrospectively analyzed. Regional thickness of EAT (EATth), total volume of EAT, total volume of paracardial adipose tissue (PAT) and total volume of AVAT from L2 to L5 level were measured. The relationships between abdominal and cardiac adipose tissue measurements, the number of components of metabolic syndrome, and the severity of Agatston score on a four ranking scale (0, 1–10,11–100, 101–400, >400) were investigated.

Results

The amounts of AVAT, EAT, PAT and EATth-LAVG showed a significant linear trend with increasing number (0–5) of components in metabolic syndrome (AVAT, EAT and PAT P for trend <0.0001; EATth-LVAG P for trend <0.001). EATth at left atrioventricular groove (EATth-LAVG) showed significant linear trend with the severity of Agatston score on a four ranking scale (P for trend <0.0001). In multivariate binary regression analysis, total volume of AVAT was the sole adiposity predictor for metabolic syndrome independent to age, gender, and waist circumference (odds ratio of 1.20, 95 % CI 1.08–1.32, p < 0.001) while total volume of EAT, PAT, and EATth-LAVG were not. In contrary, EATth-LAVG was the sole adiposity predictor for Agatston score >400 (odds ratio of 1.11, 95 % CI 1.034–1.184, p = 0.004).

Conclusions

Excessive total volume of AVAT appears to be preferentially associated with metabolic syndrome; while EAT, esp. EATth-LAVG is preferentially associated with coronary artery disease. This differential effect of the two adiposities deserves a large-scale cohort study for further investigation.

Shared genetic variance between obesity and white matter integrity in Mexican Americans

Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18–81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m²) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h² = 0.58), WC (h² = 0.57), and FA (h² = 0.49). FA shared significant portions of genetic variance with BMI in the genu (ρG = −0.25), body (ρG = −0.30), and splenium (ρG = −0.26) of the corpus callosum, internal capsule (ρG = −0.29), and thalamic radiation (ρG = −0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (ρG = −0.39, p = 0.020; ρG = −0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors.

Surrogate markers of visceral adiposity in young adults: waist circumference and body mass index are more accurate than waist hip ratio, model of adipose distribution and visceral adiposity index

Surrogate indexes of visceral adiposity, a major risk factor for metabolic and cardiovascular disorders, are routinely used in clinical practice because objective measurements of visceral adiposity are expensive, may involve exposure to radiation, and their availability is limited. We compared several surrogate indexes of visceral adiposity with ultrasound assessment of subcutaneous and visceral adipose tissue depots in 99 young Caucasian adults, including 20 women without androgen excess, 53 women with polycystic ovary syndrome, and 26 men. Obesity was present in 7, 21, and 7 subjects, respectively. We obtained body mass index (BMI), waist circumference (WC), waist-hip ratio (WHR), model of adipose distribution (MOAD), visceral adiposity index (VAI), and ultrasound measurements of subcutaneous and visceral adipose tissue depots and hepatic steatosis. WC and BMI showed the strongest correlations with ultrasound measurements of visceral adiposity. Only WHR correlated with sex hormones. Linear stepwise regression models including VAI were only slightly stronger than models including BMI or WC in explaining the variability in the insulin sensitivity index (yet BMI and WC had higher individual standardized coefficients of regression), and these models were superior to those including WHR and MOAD. WC showed 0.94 (95% confidence interval 0.88-0.99) and BMI showed 0.91 (0.85-0.98) probability of identifying the presence of hepatic steatosis according to receiver operating characteristic curve analysis. In conclusion, WC and BMI not only the simplest to obtain, but are also the most accurate surrogate markers of visceral adiposity in young adults, and are good indicators of insulin resistance and powerful predictors of the presence of hepatic steatosis.

Ectopic cardiovascular fat in middle-aged men: effects of race/ethnicity, overall and central adiposity. The ERA JUMP study

BACKGROUND/OBJECTIVES

Higher volumes of ectopic cardiovascular fat (ECF) are associated with greater risk of coronary heart disease (CHD). Identifying factors that are associated with ECF volumes may lead to new preventive efforts to reduce risk of CHD. Significant racial/ethnic differences exist for overall and central adiposity measures, which are known to be associated with ECF volumes. Whether racial/ethnic differences also exist for ECF volumes and their associations with these adiposity measures remain unclear.

SUBJECTS/METHODS

Body mass index (BMI), computerized tomography-measured ECF volumes (epicardial, pericardial and their summation) and visceral adipose tissue (VAT) were examined in a community-based sample of 1199 middle-aged men (24.2% Caucasians, 7.0% African-Americans, 23.6% Japanese-Americans, 22.0% Japanese, 23.2% Koreans).

RESULTS

Significant racial/ethnic differences existed in ECF volumes and their relationships with BMI and VAT. ECF volumes were the highest among Japanese-Americans and the lowest among African-Americans. The associations of BMI and VAT with ECF differed by racial/ethnic groups. Compared with Caucasians, for each 1-unit increase in BMI, African-Americans had lower, whereas Koreans had higher increases in ECF volumes (P-values<0.05 for both). Meanwhile, compared with Caucasians, for each 1-unit increase in log-transformed VAT, African-Americans, Japanese-Americans and Japanese had similar increases, whereas Koreans had a lower increase in ECF volumes (P-value<0.05).

CONCLUSIONS

Racial/ethnic groups differed in their propensity to accumulate ECF at increasing level of overall and central adiposity. Future studies should evaluate whether reducing central adiposity or overall weight will decrease ECF volumes more in certain racial/ethnic groups. Evaluating these questions might help in designing race-specific prevention strategy of CHD risk associated with higher ECF.

Neck circumference as an independent predictive contributor to cardio-metabolic syndrome

Background

The predictive potentials of neck circumference (NC) for cardio-metabolic risks remain uncertain. The aim of this study was to investigate whether NC independently contributes to the prediction of cardio-metabolic risks beyond body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHpR) in a large Chinese population.

Methods

A total of 4201 participants (2508 men and 1693 women) aged 20-85 were recruited from the Health Examination Centre between May 2009 and April 2010, anthropometric indices, biochemical and clinical parameters were measured. Receiver operating characteristic, partial correlation and logistic regression analyses were employed to evaluate the association of the anthropometric indices to cardio-metabolic risks separately by gender.

Results

Neck circumference was positively correlated with SBP and DBP (r=0.250 and 0.261), fasting blood glucose (FBP) (r=0.177), TG (r=0.240), TC (r=0.143) and LDL-C (r=0.088) and negatively correlated with HDL-C (r=-0.202) in males (all P<0.01). Similar results were found in females with the exception of TC. The AUCs of NC for metabolic abnormalities ranged from 0.558 (Increased LDL-C) to 0.683 (MS-rf) in men and 0.596 (Increased LDL-C) to 0.703 (MS-rf) in women (P<0.01). The NC of ≥37 cm for men and ≥33 cm for women were the best cut-off points for metabolic syndrome. The adjusted ORs (95% CIs) of NC in men and women respectively were 1.29 (1.12-1.48) and 1.44 (1.20-1.72) for metabolic syndrome risk factors (MS-rf), 1.15 (1.01-1.32) and 1.22 (1.03-1.46) for high BP, 1.16 (1.02-1.33) and 1.42 (1.18-1.71) for increased TG, and 1.26 (1.06-1.50) and 1.32 (1.06-1.65) for increased FBP; the adjusted OR of NC in women for decreased HDL-C was 1.29 (1.10-1.51).

Conclusions

Neck circumference was significantly associated with cardio-metabolic risk factors and independently contributed to the prediction of cardio-metabolic risks beyond the classical anthropometric indices in adults of China.

New Obesity Indices and Adipokines in Normotensive Patients and Patients With Hypertension

We compared the obesity parameters and selected adipokines—leptin, adiponectin, and resistin—in obese patients with hypertension and normotensive patients. A total of 67 nondiabetic obese outpatients were divided into 2 groups: A–hypertensive and B–normotensive. Serum levels of leptin, adiponectin, resistin, and insulin were measured. Weight, height, waist circumference, and hip circumference were measured to calculate waist-to-hip ratio (WHR), weight-to-height ratio, visceral adiposity index, and body adiposity index (BAI). Among patients with hypertension, significant positive correlations were observed between leptin and body mass index and BAI ( r = .31 and r = .63, respectively). In normotensive patients, leptin positively correlated with BAI ( r = .73, P < .01) and negatively with WHR ( r = −.55, P < .0001); adiponectin negatively correlated with WHR ( r = .38, P < .01) and BAI ( r = .52; P < .0001), and resistin negatively correlated with WHR ( r = −.36, P < .05). In conclusion, visceral obesity and leptin are associated with hypertension in obese patients.

Predictors of insulin resistance in patients with obesity: a pilot study

We compared adipokines and inflammatory markers in obese insulin-sensitive (group A, n = 16) and insulin-resistant (group B, n = 48) patients divided according to homeostasis model assessment of insulin resistance (HOMA-IR). Serum levels of adiponectin, leptin, resistin, high-sensitivity C-reactive protein, interleukin 6, and tumor necrosis factor α were measured. Weight, height, waist (WC) and hip circumferences, waist to hip ratio , weight to height ratio, visceral adiposity index (VAI), and body adiposity index (BAI) were measured. The WC and VAI were significantly higher in group B (113.9 ± 11.1 vs 105.3 ± 9.8 cm; P < .01 and 2.3 ± 1.1 vs 1.6 ± 0.9; P < .05, respectively), while serum adiponectin levels were higher in group A (24.5 ± 14.6 vs 15.1 ± 9.6 ng/mL; P < .005). The BAI strongly correlated with adiponectin and leptin in group B (r = .479; P < .001 and r = .705; P < .001). Insulin resistance is associated with visceral adiposity described by VAI and WC. The BAI may be a useful index in obese patients, especially with insulin resistance.

Contribution of body mass index to postoperative outcome in minority patients

OBJECTIVE

The purpose of this investigation was to examine the association of body mass index (BMI) category with short-term outcomes in minority surgical patients-a relationship that previously has not been well characterized.

METHODS

Data from the National Surgical Quality Improvement Program were used to calculate the BMI of minority patients undergoing surgery from 2005 to 2008. Patients were stratified into 5 BMI classes. Stepwise logistic regression was used to calculate odds ratios for mortality after controlling for known clinically relevant covariates.

MAIN OUTCOME MEASURES

Morbidity and mortality at 30 days, across all 5 BMI classes.

RESULTS

Among 119,619 minority patients studied, 50% were African American, 36% Hispanic, 10% Asian and Pacific Islanders, and 4% American Indian and Alaskan natives. Seventy percent were overweight or obese. Women were more likely to be obese or severely obese. The overall mortality rate was 1.5%, and this varied significantly by BMI class. Distribution of 30-day mortality demonstrated a progressive decrease, with the highest risk of death in the underweight class, and the lowest risk of death in the severely obese class. This relationship was maintained, even in patients with at least 1 major postoperative complication.

CONCLUSION

The prevalence of being overweight or obese was high in this nationally representative cohort of minority surgical patients. Although BMI class is a significant predictor of 30-day mortality, the effect appeared paradoxical. The poorest outcomes were in the underweight and normal BMI patients. Severely obese patients had the lowest risk of mortality, even after experiencing a major postoperative complication.

Direct relationship of body mass index and waist circumference with body tissue distribution in elderly persons

OBJECTIVES

To explore the relationship of BMI and WC with muscle/adipose tissue mass ratios and with trunk adipose tissue distribution, based on an anatomical 5-compartment model, by dissection of cadavers of elderly persons.

DESIGN

Cross-sectional explorative study.

SETTING

Brussels Cadaver Analysis Study.

PARTICIPANTS

Cadavers of twenty-nine white Caucasian elderly persons (17 females and 12 males, aged 78.1±6.9 years).

MEASUREMENTS

Whole body and trunk composition were determined at the anatomical tissue-system level by direct dissection.

RESULTS

BMI and WC were significantly and positively related to absolute tissue masses in both sexes. Muscle tissue mass, adipose tissue mass and trunk internal adipose tissue mass correlated better with BMI (r-values between 0.68 and 0.89) than with WC (r-values between 0.49 and 0.71). BMI was significantly and inversely related with various muscle/adipose tissue ratios in both sexes (r-values between -0.54 and -0.68). WC correlated with muscle/adipose tissue ratios in females only (r-values between -0.55 and -0.64). BMI was also significantly related to trunk adipose tissue distribution in elderly females, but not in males. When comparing individual tissue proportions within and between adjacent BMI-classifications or WC categories, body composition varied considerably.

CONCLUSION

Our results show that BMI and WC are significantly related with adipose tissue mass and with several ratios of muscle to adipose tissue in elderly subjects. However, cautious clinical interpretation is warranted since important differences in tissue mass proportions were found in subjects with similar BMI and/or WC values.

Role of beta-cell dysfunction, ectopic fat accumulation and insulin resistance in the pathogenesis of type 2 diabetes mellitus

In the natural history of type 2 diabetes (T2DM), individuals progress from normal glucose tolerance (NGT) to impaired glucose tolerance (IGT) to overt T2DM and this progression has been demonstrated in populations of diverse ethnic background. It is widely recognised that both insulin resistance and beta-cell dysfunction are important in the pathogenesis of glucose intolerance. In populations with a high prevalence of T2DM, insulin resistance is well established long before the development of any impairment in glucose homeostasis, particularly in subjects with ectopic fat accumulation. However, as long as the beta cell is able to secrete sufficient amounts of insulin to offset the severity of insulin resistance, glucose tolerance remains normal. This dynamic interaction between insulin secretion and insulin resistance is essential to the maintenance of NGT and interruption of this crosstalk between the beta cell and peripheral tissues results in the progressive deterioration of glucose homeostasis. In this paper the role of beta-cell function is reviewed, as well as the role of ectopic fat accumulation and insulin resistance in the development of type 2 diabetes.

Ectopic fat and cardiovascular disease: what is the link?

AIM

of this paper is to review the recent literature on the relationship between ectopic fat accumulation and cardiovascular disease.

DATA SYNTHESIS

Ectopic fat is an important predictor of metabolic (in particular insulin resistance) and cardiovascular disease, carrying more risk than general fat accumulation. Recent studies have shown a link between ectopic fat accumulation, as cardiac (epicardial or intra-myocardial fat) and/or visceral and/or hepatic fat, and development of atherosclerosis, coronary heart disease and hypertension.

CONCLUSIONS

Ectopic fat accumulation is not only a marker of cardiometabolic disease, since through the release of adipocitokines, lipotoxic and glucotoxic agents, participates in the crosstalk with insulin-sensitive organs leading to metabolic, cardiac and vascular dysfunctions.

Insulin resistance, adipose depots and gut: interactions and pathological implications

This review article focuses on the many metabolic actions of insulin at the level of muscle, liver and adipose tissue. In terms of pathogenetic mechanisms, the condition of insulin resistance is complex, as multiple genetic and environmental factors, among which an increasingly sedentary lifestyle associated with high-fat diet, mutually interact according to variable patterns in time in any given individual. It is well recognized that obesity (in particular abdominal obesity) favours the development of insulin resistance. Here we evaluate the impact of obesity and ectopic fat accumulation (visceral and hepatic) on insulin resistance at the level of different target organs, i.e., muscle, liver and adipose tissue. The roles of the gut and the liver, in particular of bile acids and gut microflora, are also discussed as possible determinants of energy balance and glucose metabolism.

Neck circumference as a measure of central obesity: associations with metabolic syndrome and obstructive sleep apnea syndrome beyond waist circumference

BACKGROUND & AIMS

To investigate the relationship of neck circumference (NC) to metabolic syndrome (MetS) and obstructive sleep apnea syndrome (OSAS) and whether it adds information to that provided by waist circumference.

METHODS

Cross-sectional analysis of a population sample of 1,912 men and women, aged 55.1 +/- 12 years, representative of Turkish adults. MetS was identified based on modified criteria of the ATP-III, OSAS when habitual snoring and episodes of apnea were combined with another relevant symptom.

RESULTS

NC measured 36.7 (+/- 3.5) cm in the total sample. It was significantly correlated with numerous risk factors, above all body mass index and waist girth (r > or = 0.6), homeostatic model-assessed insulin resistance, blood pressure and, inversely, with smoking status and sex hormone-binding globulin. Sex- and age-adjusted NC was associated significantly with MetS, at a 2-3-fold increased likelihood for 1 standard deviation (SD) increment. After further adjustment for waist circumference and smoking status, a significant residual odds ratio (OR, 1.13 [95% CI 1.08; 1.19]) persisted, corresponding to ORs of 1.53 and 1.27 in males and females, respectively, for 1 SD increment. Even when adjusted for all MetS components, a residual OR (1.08 [95% CI 1.000; 1.17]) remained. Sex- and age-adjusted NC was associated significantly also with OSAS in genders combined, independent of waist girth, yielding an added OR of 1.3 for 1 SD increment.

CONCLUSIONS

NC contributes to MetS likelihood beyond waist circumference and the MetS components. Regarding association with OSAS, NC is of greater value than WC among Turkish men, not women.