Conceptos generales de epigenética: proyecciones en pediatría / General concepts of epigenetics: projections in paediatrics

La asociación entre factores ambientales presentes durante el desarrollo embrionario/fetal y enfermedades que puedan presentarse durante la vida representa un campo de creciente interés. En este contexto la evidencia actual apoya fuertemente que alteraciones en el crecimiento intrauterino y durante los primeros años de vida presentan una fuerte influencia en el riesgo de padecer enfermedades crónicas que en muchos casos pudiera ser mayor que la carga genética del paciente. La persistencia y reproducibilidad de los fenotipos asociados a alteraciones en el desarrollo temprano sugieren la participación de mecanismos moleculares que registran dichas modificaciones (i.e. mecanismos epigenéticos) generando una «reprogramación¼ celular y fisiológica. Esta revisión es la introducción a una serie de 5 artículos en torno a la participación de los mecanismos epigenéticos en el desarrollo de enfermedades crónicas (i.e. cardiovasculares, metabólicas, asma/alergias y cáncer) y su relación con el origen de dichas enfermedades en etapas tempranas del desarrollo. El objetivo de esta serie es mostrar el estado actual de esta área de la investigación y presentar los desafíos e interrogantes futuros en los cuales la pediatría tiene un papel preponderante, desarrollando estrategias para la prevención, detección precoz y seguimiento.

Current evidence supports the notion that alterations in intrauterine growth and during the first years of life have a substantial effect on the risk for the development of chronic disease, which in some cases is even higher than those due to genetic factors. The persistence and reproducibility of the phenotypes associated with altered early development suggest the participation of mechanisms that would record environmental cues, generating a cellular reprogramming (i.e. epigenetic mechanisms). This review is an introduction to a series of five articles focused on the participation of epigenetic mechanisms in the development of highly prevalent chronic diseases (i.e. cardiovascular, metabolic, asthma/allergies and cancer) and their origins in the foetal and neonatal period. This series of articles aims to show the state of the art in this research area and present the upcoming clues and challenges, in which paediatricians have a prominent role, developing strategies for the prevention, early detection and follow-up.

Nivel sérico de folato y vitamina B12 en adultos mayores chilenos: Resultados de la Encuesta Nacional de Salud ENS 2009-2010 / Serum folate and vitamin B12 in older people: Results from the Chilean national health survey 2009-2010

Supraphysiological levels (SFL) of serum folate (SF) derived from flour fortification with folic acid (FA) could be risky among older adults with low vitamin B12 (B12) levels. Aim: To describe and analyze SF and B12 levels in older Chileans and to identify risk groups. Material and Methods: Participants were 1.043 older people aged ≥ 65 years from the National Health Chilean Health Survey 2009-2010 (ChNHS 2009-10), a multistage stratified random sample, representative of the national population. SF (µg/L) and B12 (pg/ml) were determined in fasting samples by competitive chemoluminescence immunoassay. Mean, deciles and percentiles 5 and 95th were calculated. We defined SF categories: < 4.4 (deficit); 4.41-20 (normal) and SFL: 20.01-25.6; 25.6-29 and > 29 µg/L (80th percentile of the distribution) and vitamin B12 categories: ≤ 200 (deficit); 200.1-299.5 (marginal deficit) and > 299.5 (normal). Prevalence rates, multiple and logistic regression models were used and adjusted by sex and age, educational level and residence area. Results: SF and B12 mean and 95th percentiles were 21.2 ± 0.56/38.6 µg/L and 348.4 ± 7.6/637(pg/ml) respectively. Forty nine percent of participants had SFL. Folate and B12 deficiency were present in 0.3 and 8.1% of participants, respectively. Men had significantly lower prevalence of SFL > 29 µg/L (OR adjusted odds ratio 0.47 95% confidence intervals: 0.26-0.84). B12 showed no significant variation by age and sex. The prevalence of SFL associated with B12 deficiency was 4.1%. No statistically significant association was observed between levels of folate and B12. Conclusions: Folate deficit is almost inexistent, but a significant percentage of participants had SFL suggesting the need for revising the current wheat flour fortification levels.

Obesidad y cáncer en Chile: estimación de las fracciones atribuibles poblacionales / Obesity and cancer in Chile: Estimation of population attributable fractions

Background: Obesity is a risk factor for the development of certain types of cancer. Aim: To estimate the proportion of cancers potentially attributable to obesity in men and women in Chile based on the calculation of population attributable fractions (PAF %). Material and Methods: Cancer sites studied were those where obesity is a known risk factor based on the updated World Cancer Research Fund (WCRF) analysis. Namely, colorectal, endometrium, esophagus, breast, pancreas, kidney and gallbladder cancers were analyzed. Overall and specific PAFs% were calculated for cancer sites and sex from known estimates of relative risk and national prevalence of overweight and obesity. Results: The overall estimates of cancer PAF% for obesity were approximately 20%, without differences between men and women. Highest cancer PAFs% were for endometrial (47%) in women, and esophageal (35%) and pancreatic (31%) in men. The largest sex differences in PAFs% were for gallbladder (higher in women) and colorectal (higher in men). Results are closer to those reported from developed countries (USA and United Kingdom) than those from developing countries (Brasil, China). Conclusions: In Chile about 20% of all cancers could be prevented by obesity prevention and control strategies.

Prevención de la desnutrición de la madre y el niño: el componente de nutrición de la Iniciativa Salud Mesoamérica 2015 / Preventing maternal and child malnutrition: The nutrition component of the Mesoamerican Health Initiative 2015

Describir un plan maestro para el desarrollo de planes nacionales para prevenir la desnutrición materno-infantil en Mesoamérica en un plazo de cinco años. Para ello se elaboró un análisis sobre los principales problemas, políticas y programas de nutrición en Mesoamérica. A partir del análisis y de la revisión de la literatura sobre las mejores prácticas en el combate a la desnutrición, el Grupo Técnico de Nutrición desarrolló, discutió y validó el plan durante varias reuniones presenciales. Se desarrolló la teoría de cambio que identifica los problemas y barreras, las acciones propuestas, los cambios e impactos esperados. Se propone la implementación de paquetes de intervenciones para reducir la desnutrición y deficiencia de micronutrientes de utilidad para diversos contextos epidemiológicos. El plan maestro de nutrición constituye un insumo que puede facilitar la elaboración de propuestas de programas y políticas dirigidos a reducir la desnutrición y promover la toma de decisiones basadas en evidencia.

To describe the regional master plan of nutrition to address maternal and child malnutrition in a 5- year period developed by the Nutrition Technical Group. The Nutrition Technical Group developed a situation analysis describing the main nutrition problems, policies and programs in Mesoamerica. The situation analysis and a literature review about effective interventions to address malnutrition were conducted to develop a nutrition master plan. The Nutrition Technical Group held various meetings to develop, discuss and validate the master plan. Theory of change identified problems and barriers, the actions to be developed, the changes and impacts expected. A package of interventions is proposed to reduce undernutrition and micronutrient deficiencies useful under different epidemiological contexts. The nutrition master plan provides a guideline of best practices that can be used for evidence-informed decision making and the development of national policies and programs to reduce malnutrition.

Cambios en el consumo aparente de nutrientes en el Gran Santiago 1988-1997 en hogares según ingreso y su probable relación con patrón de enfermedades crónicas no transmisibles / Changes in household food and nutrient consumption in Metropolitan Santiago 1988-97 by income

Background: The rise in the prevalence of obesity, diabetes, and other risk factors for cardiovascular diseases and cancer observed in Chile over the past decades may be related to changes in dietary patterns of the population. Aim: To report changes in household apparent food-nutrients consumption (HAFNC) for Metropolitan Santiago-Chile 1988-97. Material and Methods: The analysis is based on data from household expenditure surveys conducted by the Instituto Nacional de Estadísticas (INE) on a representative sample of the population to define changes in food prices. Information on food and drink purchases were grouped by specific items and expen-ditures standardized across the two surveys. HAFNC was determined based on unit consumed at home and out of home by the total group and by income quintile using national food composition tables. Results: Apparent energy consumption increased over the study period by 25 percent, this was mainly explained by increased consumption of meat and dairy (rich in saturated fats of animal origin) and of processed foods (fat spreads, sweets and pastries) and foods rich in added sugars (sugary drinks and juices). Dietary fiber derived from whole grains, legumes and cereals decreased. The HAFNC of items protective against nutrition related chronic diseases, such as vegetables, fruits and other fiber rich foods remained stable or frankly decreased (legumes and non-starchy vegetables) Fish and other marine foods rich in omega- 3 fats remained low. Conclusions: The changes in apparent food consumption patterns can be characterized by an increase in energy dense, fat and sugar rich foods with a low consumption of fi sh, whole grains, legumes, vegetables and fruits.

Fortificación de la harina de trigo con ácido fólico en Chile: Consecuencias no intencionadas / Flour fortifcation with folic acid in Chile: Unintended consequences

Background: High daily intake of folic acid (FA) could determine health risks in some populations. Aim: To review the Chilean FA wheat four fortifcation and to identify the existence of populations at risk. Material and Methods: We categorized the FA levels in four samples (percentil P) (2005-2008) and estimated intake of FA (mg/d) in adults from apparent bread consumption according to different levels (P20, 50 and 95) and children consumption (8-13 years) considering socioeconomic status (SES), bread/g/d intake (P20, 50 and 75) and regulated level of four fortifcation (2.2 mg FA/100 g). Daily Dietary Folate Equivalent (DFE) consumption was estimated from serum folate in adults and elderly people (both sexes). We calculated the percentage of population with FA intakes over the estimated average requirement (EAR) and maximum level (UL) pre and post-fortifcation. Results: There is great variability in FA four: 10-20 percent samples without FA and 10-30 percent with levels > 2.2 mg/100 g. Adult daily consumption (2-4 day/loaves) could determine FA intakes close to UL. Children daily bread consumption (low socioeconomic level) > P75 have intakes close to UL. Post-fortifcation estimated daily DFE from serum folate in women, men and elderly people show: 99 percent of women, 100 percent of men and the elderly people have intakes higher than EAR. Additionally 2.3 percent of women and 6 percent of men would have intakes near the UL. Conclusions: The four FA levels and serum folate levels in some populations show increased FA post-fortifcation intakes, which could lead to greater risk suggesting a revision of the fortifcation level.

Déficit de vitamina B-12 en adultos mayores: ¿Un problema de salud pública en Chile? / Prevalence of vitamin B-12 deficiency in older adults

Background: There is a correlation between aging and the decrease of plasma levels of vitamin B-12. Aim: To determine the prevalence of vitamin B-12 and folate deficiency and its hematological impact among older adults (AM). Material and Methods: Cross-sectional study, in 1028 subjects aged 65 to 87years, living in community and evaluated between 2005 and 2008. Percentile distribution of vitamin B-12, folate, hemoglobin, packed red cell volume and mean cell volume by gender and age were analyzed. Deficiency was defined as vitamin B-12 levels < 148 pmol/L, marginal deficiency as vitamin B-12 levels < 221 pmol/L, anemia was defined as a hemoglobin < 13 and 12 g/dL among men and women, respectively. Results: The prevalence of vitamin B-12 deficiency was 12 percent and the figure for marginal deficiency was 25.4 percent. Males were more affected than females (p < 0.001). The frequency of anemia was 8.6 percento, and was higher among women (p = 0.004). Conclusions: There is a high prevalence of full blown and marginal deficit of vitamin B-12 among the elderly. This deficiency should be considered for correction through public nutrition policies.

Cumplimiento de la guía clínica de manejo ambulatorio de la neumonía adquirida en la comunidad en personas mayores en centros de atención primaria de salud de Santiago / Compliance with guidelines for the management of community acquired pneumonia at primary health care centers

Background: Community acquired pneumonia (CAP) has a high mortality rate among older people. To increase its treatment efficiency, the Chilean Ministry of Health elaborated a clinical management guideline for CAP. Aim: To assess the degree of compliance with the clinical guidelines for CAP among professionals working at primary health care centers. Material and methods: A follow up of a cohort of 2,797 subjects aged 67 years or more, incorporated to a clinical study. All cases of bronchopneumonia or pneumonia diagnosed at primary health care centers between September 2005 and June 2008 were recorded. Results: During the follow up period, 192 cases of CAP were diagnosed. A chest X-ray was requested in 81 percent of cases and a confirmation consultation was done in 58 percent. Amoxicillin/ Clavulanic acid was the most common antimicrobial prescription in 61 percent of cases, followed by Clarithromycin in 17 percent and Amoxicillin in 12 percent. The antimicrobial used was not registered in 5 percent of cases. Conclusions: The clinical guidelines improve the efficiency of CAP treatment and decrease complications. However, these guidelines must been complemented with an adequate training and supervision of health care teams.

Cambios en la disponibilidad de alimentos en el Gran Santiago por quintiles de ingreso 1988-1997 / Changes in food availability in metropolitan Santiago Chile according to income (quintiles) 1988-1997

Se presentan los cambios en la disponibilidad de alimentos en hogares del Gran Santiago 1988-1997, obtenidos por muestra representativa y se analiza posible relación con los cambios en el perfil epidemeológico nacional. Se evaluó el ítem gasto de alimentos/bebidas de la IV y V Encuesta de Presupuestos Familiares, realizada por INE cada 10 años para calcular el Indice de Precios al Consumidor (IPC). Se ordenaron los alimentos por grupo homologando el gasto en alimentos entre ambas encuestas; asignando precios según productos; se determinaron las unidades físicas de alimentos consumidos dentro y fuera del hogar. El gasto en alimentos aumentó, determinando una mayor disponibilidad de alimentos para el total hogares y quintiles de ingreso, incrementándose más en quintiles más pobres. Se eleva el consumo aparente de cereales procesados, productos de pastalería, carnes de ave y cerdo, lácteos procesados, jugos preparados y bebidas, cremas, mayonesa, comidas preparadas para llevar al hogar y comidas fuera del hogar. Pescados, verduras y frutas aumentan levemente con una gran disminución de las legumbres. El perfil alimentario actual se caracteriza por mayor disponibilidad de productos de origen animal y alimentos procesados; aumentando la densidad energética, calorías grasas, grasas saturadas, azúcares simples de alto índice glicémico; baja la disponibilidad de alimentos aportadores de antioxidantes, fitoquímicos, fibra dietaria y ácidos grasos omega 3. Estos cambios probablemente han impactado notablemente el perfil epidemeológico y nutricional del país, manifestándose por aumento epidémico de la obesidad, y las enfermedades crónicas relacionadas con la dieta y la inactividad física.

Acción de los Gobiernos en el combate de la malnutrición: analisis critico de resultados / Action of the governments against malnutrition: critical analysis of results

Se examina en forma crítica, el porque de la acción gubernamental, las prioridades reales que mueven a los gobiernos en la acción, la limitación en la evaluación de los resultados, el tipo de programa de combate a la malnutrición, análisis crítico de los resultados de algunos programas y una orientación multidisciplinaria integrada para la acción gubernamental en el problema alimentario nutricional