Imágenes en obesidad: contribuyendo a un entendimiento más profundo de la enfermedad / Imaging in obesity: contributing to a deeper understanding of the disease

Resumen: la obesidad constituye un problema mayor de salud pública relevante en la actualidad, considerando que cumple un doble rol al actuar como factor de riesgo para la mayoría de las enfermedades crónicas no transmisibles y constituir una entidad nosológica independiente. Los estudios de imágenes han contribuido, desde diferentes perspectivas, a dilucidar los mecanismos propios de la enfermedad, sus complicaciones, progresión, mecanismos cognitivos involucrados y respuesta a diversos esquemas terapéuticos. El objetivo del presente artículo es proveer de una visión general respecto a cómo los estudios imagenológicos, especialmente basados en resonancia magnética, han profundizado la comprensión de los mecanismos metabólicos y neurocognitivos, relacionados, así como elementos vinculados al tratamiento. Adicionalmente se discuten posibles direcciones futuras en este campo.

Abstract: Obesity constitutes a relevant issue in public health. It acts both like a risk factor for most of the non-communicable diseases and as an independent nosologic entity. The imaging studies have contributed, from several perspectives, to elucidate the underlying mechanisms of the disease. its complications, progression, involved cognitive phenomena and the response to different therapeutic approaches. The objective of this article is to provide a global view about how the imaging studies, particularly those based on magnetic resonance imaging, have given a deeper comprehension of the related metabolic and cognitive mechanisms and some facts related to the treatment. Additionally, future directions of this field are discussed.

Agreement between software programmes of body composition analyses on abdominal computed tomography scans of obese adults

ABSTRACT Objective A large number of studies have used abdominal computed tomography (CT) to quantify body composition, and different software programmes have been used to perform these analyses. Thus, this comparison is important to enable researchers to know the performance of more accessible software. Subjects and methods Fifty-four abdominal CT scans of obese (BMI 30 to 39.9 kg/m2), sedentary adults (24-41 years) patients from a Brazilian single center were selected. Two software programs were compared: Slice-O-Matic (Tomovision, Canada) version 5.0 and OsiriX version 5.8.5. The body composition analysis were segmented using standard Hounsfield unit (HU) (adipose tissue: -190 to +30 and skeletal muscle: -29 to +150) and measured at the mid third lumbar vertebra (L3) level on a slice showing both transversal processes. Bland-Altman limits of agreement analyses were used to assess the level of agreement between Slice-O-Matic and OsiriX. Results A total of fifty-four participants were evaluated, with majority women (69%), mean of age 31.3 (SD 6.5) years and obesity grade I most prevalent (74.1%). The agreement, in Bland-Altman analysis, between Slice-O-Matic and OsiriX analisys for the muscle mass tissue, visceral adipose tissue and subcutaneous adipose tissue were excellent (≥ 0.954) with P-values < 0.001. Conclusion These findings show that Slice-O-Matic and OsiriX softwares agreement in measurements of skeletal muscle and adipose tissue and sarcopenia diagnosis in obese patients, suggesting good applicability in studies with body composition in this population and clinical practice.

Intra-abdominal fat measurement by ultrasonography: association with anthropometry and metabolic syndrome in adolescents / Gordura intra-abdominal medida por ultrassonografia: relação com antropometria e síndrome metabólica em adolescentes

Abstract Objective: To associate intra-abdominal fat thickness measured by ultrasonography to the factors related to metabolic syndrome and to determine cutoff points of intra-abdominal fat measurement associated with a greater chance of metabolic syndrome in adolescents. Methods: This was a cross-sectional study, with 423 adolescents from public schools. Intra-abdominal fat was measured by ultrasonography. Anthropometric data were collected, and biochemical analyses were performed. Results: Intra-abdominal fat was measured by ultrasonography, showing a statistically significant association with the diagnosis of metabolic syndrome (p = 0.037), body mass index (p < 0.001), elevated triglyceride levels (p = 0.012), decreased plasma HDL levels (p = 0.034), and increased systemic blood pressure values (p = 0.023). Cutoff values of intra-abdominal fat thickness measurements were calculated by ultrasound to estimate the individuals most likely to develop metabolic syndrome. In the logistic regression models, the cutoff values that showed the highest association with metabolic syndrome in males were 4.50, 5.35, 5.46, 6.24, and 6.50 cm for the ages of 14, 15, 16, 17, and 18/19 years, respectively. In the female gender, the cutoff values defined for the same age groups were 4.46, 4.55, 4.45, 4.90, and 6.46 cm. In an overall analysis using the ROC curve, without gender and age stratification, the cut-off of 3.67 cm showed good sensitivity, but low specificity. Conclusion: Ultrasonography is a useful method to estimate intra-abdominal adipose tissue in adolescents, which is associated with the main factors related to obesity and metabolic syndrome.

Resumo Objetivo: Relacionar a espessura da gordura intra-abdominal medida pela ultrassonografia aos fatores ligados à síndrome metabólica. Determinar pontos de corte da medida da gordura intra-abdominal associados a uma maior chance de síndrome metabólica em adolescentes. Métodos: Estudo seccional, com 423 adolescentes de escolas públicas. A gordura intra-abdominal foi medida pela ultrassonografia. Foram coletados dados antropométricos e feitas análises bioquímicas. Resultados: As medidas da gordura intra-abdominal por ultrassonografia apresentaram associação estatisticamente significativa com o diagnóstico de síndrome metabólica (p = 0,037), índice de massa corporal (p < 0,001), níveis elevados de triglicerídeos (p = 0,012), redução dos níveis plasmáticos de HDL (p = 0,034) e aumento da pressão arterial sistêmica (p = 0,023). Calcularam-se pontos de corte da medida da espessura da gordura intra-abdominal por ultrassom, para estimar os indivíduos com mais chance para o desenvolvimento de síndrome metabólica. Em modelos de regressão logística, os pontos de corte que apresentaram maior associação com a síndrome metabólica no sexo masculino foram de 4,50, 5,35, 5,46, 6,24 e 6,50 cm para as idades de 14, 15, 16, 17 e 18/19 anos, respectivamente. No sexo feminino, os pontos de corte definidos para as mesmas faixas etárias foram de 4,46, 4,55, 4,45, 4,90 e 6,46 cm. Em análise global por meio da curva ROC, sem estratificações por sexo e idade, o ponto de corte de 3,67 cm teve boa sensibilidade, porém apresentou baixa especificidade. Conclusão: A ultrassonografia é um método útil para a estimativa do tecido adiposo intra-abdominal em adolescentes, está associada com os principais fatores relacionados à obesidade e à síndrome metabólica.

Assessment of adiposity in psoriatic patients by dual energy X-ray absorptiometry compared to conventional methods

Abstract BACKGROUND: Obesity is considered a chronic low-grade inflammatory disease that shares mediators of inflammation with psoriasis, such as TNF-α and IL-6. The relationship between these two conditions involves factors such as predisposition and response to therapy, in addition to an association with cardiovascular disease. OBJECTIVES: The aim of the present study was to investigate the prevalence of adiposity as determined by body mass index (BMI), waist circumference (WC), and dual energy X-ray absorptiometry (DXA) evaluation in patients with psoriasis. METHODS: BMI, WC and body composition by DXA were measured in 42 psoriatic patients without joint complaints and in 41 control patients using standard procedures. In the comparison between cases and controls, we used Pearson’s Χ2 test or Fisher’s exact test, and the nonparametric Mann-Whitney test. The difference between the diverse classification methods for obesity was evaluated using McNemar’s test. To test the level of agreement between those variables, we used the weighted kappa coefficient. RESULTS: There was no difference in the prevalence of obesity among cases and controls. Both BMI and WC had low agreement with measures of body fat evaluated by DXA. With the use of DXA scanning, prevalence of overweight and obesity in patients with psoriasis was 83.3%, which constitutes a strong evidence of the need for intervention on this metabolic parameter. CONCLUSION: Dual energy X-ray absorptiometry was more capable of identifying obesity compared with BMI and WC both in psoriatic and control patients.

Effect of concurrent training on gender-specific biochemical variables and adiposity in obese adolescents

Objective The purpose of the present study was to analyze the effects of a 20-week concurrent training (20 WCT) intervention program on gender-specific body composition and metabolic variables in obese adolescents.Subjects and methods Sample was composed of twenty-five obese adolescents, aged between 12 and 15 (13.4 ± 0.96) years. Fat-free mass (FFM), percentage trunk fat mass (TFM%) and percentage fat mass (%FM) were evaluated through dual-energy X-ray absorptiometry (DXA). Measurement of intra-abdominal adiposity (IAAT) was performed using ultrasound. Blood pressure was measured and blood samples analyzed for total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides (TG) and plasma glucose. All participants performed the concurrent training (combination of weight training and aerobic training) three times per week, one hour per day, for 20 weeks. Descriptive analysis and analysis of variance (ANOVA) for repeated measures were used to compare baseline, 10 week and 20 week moments using the Bonferroni post-hoc test. Statistical significance was set at p < 0.05. Significant decrease in TC, LDL-c and TFM% were verified in both genders after the 10 initial weeks of concurrent training.Results A significant increase in height was found in both the male and female groups (p = 0.001 and p = 0.047, respectively), after 20 weeks of concurrent training. In addition, several modifications were observed in body composition and metabolic variables, with a significant decrease in BMI (p = 0.002 and p = 0.017), BMI z-score (p = 0.033 and p = 0.004), FM% (p = 0.002 and p = 0.002), TFM% (p = 0.009 and p = 0.018), TC (p = 0.042 and p = 0.001) and LDL-c (p = 0.006 and p = 0.001) in the male and female groups, respectively, after 20 weeks of intervention when compared with baseline.Conclusion Our results identified that concurrent training was an effective intervention for treating metabolic variable and body composition disorders, in both genders, by decreasing adiposity with consequent improvement in BMI and BMI z-scores, and enhancement in lipid profile variables.

Evaluation of Anterior Segment Parameters in Obesity

PURPOSE: To investigate anterior segment parameters in obese patients in comparison to healthy individuals. METHODS: Thirty-four obese subjects and 34 age-sex-matched healthy subjects were enrolled in this prospective cross-sectional study. Ophthalmological examinations including intraocular pressure (IOP), central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), and axial length (AL) measurements were performed on each subject. Height and weight of all subjects were recorded and body mass index (BMI) was calculated. RESULTS: IOP was significantly higher in the obese group (p = 0.003). The mean ACD in obese subjects was significantly lower than that in control subjects (p = 0.036). AL, ACV, ACA and CCT were not significantly different between the groups. There was a positive correlation between BMI and IOP (r = 0.404, p < 0.001). ACD and ACA were negatively correlated with BMI. CONCLUSIONS: IOP was significantly higher and ACD was significantly lower in obese subjects. AL, ACV, ACA and CCT were not significantly different between the groups. The impact of obesity on anterior chamber parameters should be further investigated.

Epicardial fat thickness obese patients an observational echocardiographic study

Obesity currently affects nearly one-third of the population in the industrialized world. Traditionally, anthropometric measures such as body mass index [BMI] or waist circumference have been used to quantify overall adiposity; however, regional fat depots may be of greater importance than overall adiposity. Several studies have highlighted pericardial fat and abdominal visceral adipose tissue [VAT] as unique, pathogenic fat depot. Recognize the relation of obesity to increase epicardial fat pad thickness in Iraqi patients. Epicardial fat thickness was measured in 62 consecutive subjects [28 women 45%, 34 men 55%] mean age of 47.77 years [SD 8.03], using routine transthoracic echocardiogram. Epicardial fat was identified as the echo-free space between the outer wall of the myocardium and the visceral layer of the pericardium, and its thickness was measured perpendicularly on the free wall of the right ventricle at end-systole. The results show progressive increase of epicardial fat with increasing BMI which was very significant statistically. High mean epicardial fat is significantly associate with increasing waist circumference. No difference in those below and above 45 years of age in mean epicardial fat and there is gender difference in epicardial fat, where males had more epicardial fat than females. There is increase in the epicardial fat pad thickness in overweight and obese [BMI >/= 25] patients if compared to normal persons epicardial fat increase with increasing waist circumference more likely in male obese and independent on age.