Los pacientes con delgadez constitucional presentan un fenotipo diferente al de los pacientes con trastornos de la alimentación / Patients with constitutional thinness have a different phenotype than patients with eating disorders

Los pacientes con delgadez constitucional suelen presentar un peso habitual reducido pero estacionario en el tiempo, con dificultad para aumentarlo incluso luego de someterse a dietas hipercalóricas. A diferencia de otras entidades, no se suelen encontrar trastornos de la alimentación, enfermedades sistémicas, desnutrición o sobre-ejercitación. Sin embargo, su presencia suele despertar preocupación y motivar la búsqueda de causas patológicas asociadas, tanto por parte delos pacientes como de los profesionales de la salud. Partiendo de la viñeta clínica de una paciente que presenta estas características, el autor realiza una búsqueda bibliográfica para intentar esclarecer cuán diferentes resultan los pacientes con delgadez constitucional de aquellos que presentan el principal diagnóstico diferencial a tener en cuenta, la anorexia nerviosa. (AU)

Patients with constitutional thinness tend to have a reduced but stationary habitual weight over time, with difficulty to increase it even after undergoing hypercaloric diets. Unlike other entities, eating disorders, systemic diseases, malnutrition or over-exercising are not usually found. However, its presence tends to arouse concern and motivates the search for associated pathological causes, both by patients and health professionals. Based on the clinical vignette of a patient who presents these characteristics, the author performs a literature search in order to clarify how different patients with constitutional thinness are from those who present the main differential diagnosis to consider:anorexia nervosa. (AU)

Esteatosis hepática, grasa visceral y alteraciones metabólicas, en individuos con sobrepeso/obesidad aparentemente sanos / Hepatic steatosis, visceral fat and metabolic alterations in apparently healthy overweight/obese individuals

La observación clínica indica que muchos obesos no presentan alteraciones metabólicas importantes, por lo que el objetivo del presente estudio fue comprobar si el sobrepeso/obesidad (SP/OB) simple, no asociado a otros factores de riesgo, se acompañaba de alteraciones metabólicas; o si estaba presente el fenómeno conocido como “paradoja de la obesidad”. A 30 individuos aparentemente sanos de Maracaibo, Venezuela, entre 20 y 59 años de edad, e índice de masa corporal (IMC) superior a 25 kg/m², y a un grupo control de 11 individuos con IMC inferior a 25 kg/m², se les realizó una historia clínica, medida de parámetros antropométricos, determinaciones basales de glicemia, insulina y lípidos, medición ultrasonográfica para esteatosis hepática y ultrasonografía e impedancia bioeléctrica para estimar la grasa visceral. El estudio demostró que solo en un tercio de los individuos con SP/OB, con elevado IMC y circunferencia de cintura (CC), se encontraron concentraciones elevadas de insulina, HOMA-IR y triglicéridos. A pesar de ello, la presencia de esteatosis hepática fue muy elevada (91%) en el grupo SP/OB, si se compara con 9% en el grupo control. La grasa visceral, en el grupo control, estuvo asociada a la CC y a la glicemia; sin embargo, no se relacionó con el IMC, insulina, HOMA-IR o HDLc; mientras que en el grupo SP/OB, aunque estadísticamente elevada en relación al grupo control, reveló una pérdida de estas asociaciones. Los resultados resaltan la importancia de investigar más la presencia de esteatosis hepática en los individuos con SP/OB, que la estimación de la grasa visceral, para identificar sujetos con alto riesgo cardiometabólico.

Clinical observation indicates that many obese individuals do not display important metabolic alterations. Consequently, the objective of this study was to establish whether simple obesity, non concurrent with other important risk factors, was associated with metabolic alterations; or if the phenomenon known as “obesity paradox” was present. A clinical history, measurements of anthropometric and metabolic parameters and estimation of hepatic steatosis and visceral fat, were determined in 30, apparently healthy, individuals from Maracaibo, Venezuela, between 20 and 59 years of age and a body mass index (BMI) above 25 kg/m²,and compared to a lean control group of 11 individuals with BMI less than 25 kg/m². The study demonstrated that only one third of overweight/obese individuals (OW/OB), with high body mass index (BMI) and waist circumference (WC), presented elevated values of insulin, HOMA-IR and triglycerides. Nevertheless, the presence of hepatic steatosis was elevated in the OW/OB group (91%) vs. 9% in the control group. The visceral fat in the lean control group was associated with both, WC and glycemia; however, it was not related to the BMI or insulin, HOMA-IR and HDLc. The visceral fat in the OW/OB group, although elevated in relation to the lean group, revealed a loss of these associations. In the OW/OB it was the BMI that was associated with insulin and HOMA-IR. The results emphasize the importance of investigating for the presence of hepatic steatosis, rather than visceral fat, in individuals with OW/OB, to identify subjects with high cardiometabolic risk.

Lean adolescents with increased risk for metabolic syndrome

The aim of the present study was to determine in adolescents the relationship between insulin levels and body mass index (BMI), body fat distribution, diet, life style and lipid profile. We studied 167 adolescents (68 boys and 99 girls) whose ages ranged from 14 to 17 years. A detailed medical (including pubertal stage) and nutritional record was obtained from each subject. Biochemical measurements included fasting serum insulin, glucose, total cholesterol (TC), triglycerides (Tg), HDL-C, LDL-C and VLDL-C. HOMA insulin resistance (IR) and HOMA beta-cell function (beta-cell) were calculated. Insulin levels were over 84 pmol/L (cut off normal value in our lab) in 56 per cent of the boys and 43 per cent of the girls. Thirty-seven percent of lean adolescents whose BMI was 21.5 +/- 1.9 kg/m2 presented higher fasting insulin levels. HOMA IR, Tg, systolic (SBP) and diastolic blood pressure (DBP) values when compared to a lean normoinsulinemic group. Insulin levels were correlated (p < 0.01) with body mass index. Both boys and girls in the highest BMI quartile (BMI > 24 kg/m2) had significantly higher serum insulin, HOMA beta-cell, and Tg levels, and the lowest HDL-C levels. A high-energy intake rich in saturated fat and low physical activity were found in this lean but metabolically altered adolescents. We conclude that even with a BMI as low as 21 kg/m2 an inappropriate diet and low physical activity might be responsible for the high insulin levels and dislipidemias in adolescents.