TAMAÑO Y COMPOSICIÓN CORPORAL EN NIÑOS MEXICANOS I: IMPLICACIONES EN EL USO DEL BOD POD, DXA Y DILUCIÓN CON DEUTERIO EN LA EVALUACIÓN DE LA MASA GRASA Y MASA LIBRE DE GRASA.

Esta revisión explora la aplicación de dos modelos de análisis de composición corporal en niños. La validez del BOD, POD, DXA y del método de dilución con deuterio para estimar la grasa corporal y la masa libre contra el modelo de cuatro compartimentos es analizado. Estas técnicas están disponibles en algunas universidades e institutos de investigación en México. Hay que tener precaución particularmente cuando el DXA y BOD POD son usados como “prueba de oro” en estudios clínicos. La aplicación de testas metodologías requiere una apropiada validación en niños mexicanos.Palabras Clave: composición corporal, niños mexicanos, BOD POD, DXA, dilución con deuteriobody composition, mexican children, BOD POD, DXA, deuterium dilution techniqu

INTERACCIÓN ENTRE GENÉTICA Y ESTILO DE VIDA EN EL DESARROLLO DE LA DIABETES MELLITUS TIPO 2: EL ESTUDIO EN LOS INDIOS PIMA/ GENETIC-LIFE STYLE INTERACTIONS IN TYPE 2 DIABETES MELLITUS DEVELOPMENT: THE PIMA INDIANS STUDY

La creciente prevalencia de diabetes mellitus tipo 2 (DT2) representa un problema complejo de salud pública a nivel mundial y particularmente en países en desarrollo, incluyendo México. La DT2 es resultado de una interacción entre la predisposición genética y los cambios drásticos en el estilo de vida. El objetivo de este trabajo de revisión es explorar la interacción entre la genética y el estilo de vida sobre el desarrollo de la DT2, comparando dos grupos genéticamente relacionados, Pimas mexicanos y Pimas de Estados Unidos de América (EUA), así como dos grupos no relacionados genéticamente, pero viviendo en ambientes similares, Pimas mexicanos y no-Pimas (Blancos) de Maycoba, México. En comparación con los Pimas de EUA, los Indios Pima Mexicanos presentaron menor prevalencia de DT2 y obesidad. Asimismo, los Indios Pima Mexicanos presentaron menor consumo de grasa y fibra dietaria, y mayor nivel de actividad física. El estudio de los indios Pima nos indica que aún en poblaciones genéticamente predispuestas a estas condiciones, su desarrollo puede estar determinado principalmente por circunstancias relacionadas con el estilo de vida. ABSTRACT Globally, the increase in Type 2 Diabetes (T2D) prevalence represents a complex public health problem, particularly in developing countries, including Mexico. Type 2 diabetes results from an interaction between genetic predisposition and drastic changes in lifestyle. The aim of this review is to explore these interactions on T2D development, using the Mexican and US Pima Indians comparative study as a model; two genetic related groups, living in different environments, and Mexican Pimas and non-Pimas (Blancos) sharing a similar environment, but not the genetics. Study results showed a lower T2D and obesity prevalence in Mexican Pimas when compared with US Pimas. Likewise, Mexican Pimas had lower fat consumption, higher dietary fiber and higher physical activity than their counterparts in the US. The Pima Indians study showed that even in genetically predisposed populations, T2D development could be mainly determined by lifestyle related factors

TAMAÑO Y COMPOSICIÓN CORPORAL EN NIÑOS MEXICANOS II. EL USO DEL ÍNDICE DE MASA CORPORAL PARA LA EDAD EN LA EVALUACIÓN DEL SOBREPESO

Las relaciones entre el IMC y el porcentaje de grasa corporal difieren entre las poblaciones. Las diferencias geográficas y socioeconómicas entre las regiones de México pueden afectar a la composición corporal y el IMC no puede determinar la verdadera relación entre la masa corporal libre de grasa y de grasa. Se argumenta que las referencias de índice de masa corporal Internacional no son convenientes para ser aplicado a nivel epidemiológico nacional. Esta revisión discute el uso del índice de masa corporal para la edad en niños mexicanos. Abstract Relations between BMI and percent of body fat differ across populations. The geographical and socioeconomic differences among regions of Mexico may affect body composition and BMI cannot determine the true relation between body fat and fat free mass. It is argued that the International BMI references are not convenient to be applied a national epidemiological level. This review discusses the use of body mass index for age in Mexican children.  Palabras claves: indice de masa corporal , datos referenciales, composición corporal, sobrepeso, niños mexicano

Estimation of Insulin Resistance in Mexican Adults by the [ 13

Objective. To evaluate the efficacy of the [13C]glucose breath test for measuring insulin resistance in Mexican adults with different glycemic states. Research Design and Methods. Fifty-eight adults underwent a [13C]glucose breath test with simultaneous measurement of total CO2 production by indirect calorimetry, at baseline and 90 minutes after the ingestion of 15 g of dextrose and 25 mg of [13C]glucose. HOMA was used as a marker of insulin resistance. Results. We found an inverse correlation between HOMA and the breath test δ13CO2 (‰), r=-0.41 (P=0.001). After adjusting for total CO2 production, correlations between HOMA and fasting glucose were less strong but remained significant. An ROC curve was constructed using δ13CO2 (‰) and HOMA values; the cut-off point was 9.99‰ δ13CO2, corresponding to a sensitivity of 80.0 (95% CI: 51.9, 95.7) and a specificity of 67.4 (95% CI: 51.5, 80.9). Conclusions. The [13C]glucose breath test is a simple noninvasive procedure but was not sufficiently robust for an accurate diagnosis of insulin resistance. Our findings suggest that the test might be helpful in identifying individuals who are not IR, which in turn may contribute to improved diabetes prevention

Estudio traslacional para el manejo de la obesidad utilizando el Programa de Prevención de Diabetes “Grupo de Equilibrio de Estilo de Vida” en clínicas de primer nivel y hospitales públicos de México: protocolo de estudio

Introduction: Obesity is the main modifiable risk factor for the development of chronic diseases in Mexico. Several randomized controlled trials have shown that intensive lifestyle programs are efficacious for the management of obesity. These programs include frequent sessions (14 or more contacts in the first 6 months) focused on diet and physical activity and use a behavior change protocol. However, most Mexican primary care clinics and public hospitals apply traditional treatments for obesity management with limited results on weight loss. The purpose of the study is to evaluate the effectiveness of the Diabetes Prevention Program (DPP) “Group Lifestyle Balance” for weight loss among adults with overweight and obesity from baseline to 6 months and from baseline to 12 months in primary care clinics and public hospitals from Sonora, Mexico.Material and Methods: This is a translational, multi-center, non-controlled, 6 and 12-month follow-up clinical study with a pre-test and post-test design. Healthcare providers from two primary care clinics, two hospitals and one university clinic will be trained with the DPP protocol to implement on their patients with overweight and obesity. Body weight, body mass index, waist circumference, systolic and diastolic blood pressure, depression, quality of life and stress scales will be measured in participants receiving the program at baseline, 6 and 12 months. Biochemical parameters will be measured at baseline and 12 months. The primary outcome is the change in body weight at 6 and 12 months.Discussion: This study will provide scientific evidence of the effectiveness of the DPP protocol as a model for obesity management in real world clinical practice among the adult Mexican population.Introducción: La obesidad es el principal factor de riesgo para el desarrollo de enfermedades crónicas en México. Varios ensayos clínicos controlados han mostrado que los programas intensivos de cambio de estilo de vida son eficaces para el manejo de obesidad. Estos programas incluyen sesiones frecuentes (14 o más los primeros 6 meses), centradas en hacer mejoras en la dieta y actividad física utilizando un protocolo de cambio de comportamiento. Sin embargo, la mayoría de clínicas de primer nivel y los hospitales públicos aplican tratamientos tradicionales para el manejo de obesidad que tienen resultados limitados. El propósito del estudio es evaluar la efectividad del Programa de Prevención de Diabetes “Grupo de Equilibrio de Estilo de Vida” sobre la pérdida de peso en adultos con sobrepeso y obesidad del inicio a 6 meses y del inicio a 12 meses del seguimiento en clínicas de primer nivel y hospitales públicos de Sonora, México.Material y Métodos: Este es un estudio clínico multicéntrico traslacional, no controlado con diseño pre y post-prueba a 6 y 12 meses. Los proveedores de salud de dos clínicas de primer nivel, dos hospitales públicos y una clínica universitaria serán entrenados con el protocolo del Programa de Prevención de Diabetes, para implementarlo en sus pacientes adultos con sobrepeso y obesidad. Se medirá el peso corporal, índice de masa corporal, circunferencia de cintura, presión sistólica y diastólica, así como escalas de depresión, calidad de vida y estrés, al inicio, 6 y 12 meses. Los parámetros bioquímicos se medirán al inicio y a los 12 meses. La variable de desenlace primaria será el cambio de peso a 6 y 12 meses.Discusión: Este estudio proveerá evidencia científica de la efectividad del protocolo del Programa de Prevención de Diabetes como un modelo para el manejo de obesidad en adultos mexicanos en condiciones de la práctica clínica del mundo real

Role of the employment status and education of mothers in the prevalence of intestinal parasitic infections in Mexican rural schoolchildren

<p><b>Background:</b> Intestinal parasitic infections are a public health problem in developing countries such as Mexico. As a result, two governmental programmes have been implemented: a) "National Deworming Campaign" and b) "Opportunities" aimed at maternal care. However, both programmes are developed separately and their impact is still unknown. We independently investigated whether a variety of socio-economic factors, including maternal education and employment levels, were associated with intestinal parasite infection in rural school children.</p> <p><b>Methods:</b> This cross-sectional study was conducted in 12 rural communities in two Mexican states. The study sites and populations were selected on the basis of the following traits: a) presence of activities by the national administration of albendazole, b) high rates of intestinal parasitism, c) little access to medical examination, and d) a population having less than 2,500 inhabitants. A total of 507 schoolchildren (mean age 8.2 years) were recruited and 1,521 stool samples collected (3 per child). Socio-economic information was obtained by an oral questionnaire. Regression modelling was used to determine the association of socio-economic indicators and intestinal parasitism.</p> <p><b>Results:</b> More than half of the schoolchildren showed poliparasitism (52%) and protozoan infections (65%). The prevalence of helminth infections was higher in children from Oaxaca (53%) than in those from Sinaloa (33%) (p < 0.0001). Giardia duodenalis and Hymenolepis nana showed a high prevalence in both states. Ascaris lumbricoides, Trichuris trichiura and Entamoeba hystolitica/dispar showed low prevalence. Children from lower-income families and with unemployed and less educated mothers showed higher risk of intestinal parasitism (odds ratio (OR) 6.0, 95% confidence interval (CI) 1.6–22.6; OR 4.5, 95% CI 2.5–8.2; OR 3.3, 95% CI 1.5–7.4 respectively). Defecation in open areas was also a high risk factor for infection (OR 2.4, 95% CI 2.0–3.0).</p> <p><b>Conclusion:</b> Intestinal parasitism remains an important public health problem in Sinaloa (north-western Mexico) and Oaxaca (south-eastern Mexico). Lower income, defecation in open areas, employment status and a lower education level of mothers were the significant factors related to these infections. We conclude that mothers should be involved in health initiatives to control intestinal parasitism in Mexico.</p&gt

Body fat measurement by bioelectrical impedance and air displacement plethysmography: a cross-validation study to design bioelectrical impedance equations in Mexican adults

<p>Abstract</p> <p>Background</p> <p>The study of body composition in specific populations by techniques such as bio-impedance analysis (BIA) requires validation based on standard reference methods. The aim of this study was to develop and cross-validate a predictive equation for bioelectrical impedance using air displacement plethysmography (ADP) as standard method to measure body composition in Mexican adult men and women.</p> <p>Methods</p> <p>This study included 155 male and female subjects from northern Mexico, 20–50 years of age, from low, middle, and upper income levels. Body composition was measured by ADP. Body weight (BW, kg) and height (Ht, cm) were obtained by standard anthropometric techniques. Resistance, R (ohms) and reactance, Xc (ohms) were also measured. A random-split method was used to obtain two samples: one was used to derive the equation by the "all possible regressions" procedure and was cross-validated in the other sample to test predicted versus measured values of fat-free mass (FFM).</p> <p>Results and Discussion</p> <p>The final model was: FFM (kg) = 0.7374 * (Ht²/R) + 0.1763 * (BW) - 0.1773 * (Age) + 0.1198 * (Xc) - 2.4658. R²was 0.97; the square root of the mean square error (SRMSE) was 1.99 kg, and the pure error (PE) was 2.96. There was no difference between FFM predicted by the new equation (48.57 ± 10.9 kg) and that measured by ADP (48.43 ± 11.3 kg). The new equation did not differ from the line of identity, had a high R²and a low SRMSE, and showed no significant bias (0.87 ± 2.84 kg).</p> <p>Conclusion</p> <p>The new bioelectrical impedance equation based on the two-compartment model (2C) was accurate, precise, and free of bias. This equation can be used to assess body composition and nutritional status in populations similar in anthropometric and physical characteristics to this sample.</p

Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 $< p_{\rm{T}, assoc} < p_{\rm{T}, trig} <$ 5.0 GeV/$c$ is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range $|\eta|<0.9$. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of $v_{2}\{4\}$ to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find $v_{2}\{4\} \simeq v_{2}\{6\}\neq 0$ which is indicative of a Bessel-Gaussian function for the $v_{2}$ distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a $|\Delta\eta| > 1.4$ gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87

Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range $|\eta| < 0.8$ are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286