Development of a small panel of SNPs to infer ancestry in Chileans that distinguishes Aymara and Mapuche components

BACKGROUND: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socio-economic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. RESULTS: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors. CONCLUSIONS: We have conducted the most extensive sampling, across many different cities, of current Chilean population. Ancestry varied significantly by latitude and human development. The panel of AIMs is available to the community for estimating ancestry at low cost in Chileans and other populations with similar ancestry.

Diseño y evaluación de proceso de una intervención comunitaria para la detección precoz del primer episodio de psicosis en Chile / Design and evaluation of a community intervention for early detection of the first episode of schizophrenia

Introducción: La esquizofrenia es una enfermedad mental que genera discapacidad, afectando la calidad de vida de la persona y de sus cuidadores. Las investigaciones demuestran que un menor tiempo de psicosis no tratada durante el primer episodio se asocia con un mejor pronóstico. Objetivo: En este trabajo se describe el diseño y evaluación de proceso de una intervención comunitaria para la detección precoz del primer episodio de psicosis, que fue aplicada en tres sectores del país (comunas de Iquique, La Granja y El Bosque) ligados a un servicio de salud mental. Material y método: Para la evaluación se utilizó una metodología cualitativa de tipo etnográfica, basada en entrevistas semi-estructuradas y entrevistas grupales con los diferentes tipos de participantes (profesores, coordinadores, profesionales médicos y no médicos). Resultados: La evaluación de proceso de esta intervención permitió concluir que contribuyó al cumplimiento de los objetivos de la intervención de manera heterogénea; se obtuvo una buena participación de médicos y profesores; la capacitación fue bien evaluada. Conclusiones: Las recomendaciones principales fueron: 1) obtener respaldo político (autoridades sanitarias locales), 2) crear y mantener vínculos cercanos con el equipo investigador, y 3) adecuar la intervención a los valores y/o necesidades de la comunidad.

Introduction: Schizophrenia is a disabling mental illness that affects the quality of life of both the sufferer and their caretakers. Research has shown that quick diagnosis and treatment of the first episode is associated with better prognosis. Objective: In this paper, the design and evaluation of a community intervention for early detection of the first episode of psychosis in three sectors of the country (municipalities of Iquique, La Granja and El Bosque) is described. Materials and Methods: For the evaluation, a qualitative, ethnographic methodology was used, based in semi-structured and group interviews with different categories of participants (teachers, coordinators, medical professionals and non-medical professionals). Results: Evaluation of this intervention shows that the objectives were fulfilled unequally. A high level of participation was obtained from doctors and teachers, and the training was positively evaluated. Conclusions: The main recommendations were, 1) obtain political support (local health authorities), 2) create and manage close relationships within the research team, and 3) modify the intervention to serve the needs and values of each community.

Estudio de prevalencia del consumo de drogas en escolares de Enseñanza Básica, a través de la metodología de pares / Prevalence of drug abuse among children in basic schools

Background: Peer methodology (PM) is an adaptation of the privileged access interviewer methodology and is used for prevalence studies. PM estimates higher drug consumption frequencies among school and college students than self reports, since it minimizes underreporting. Aim: To assess drug abuse among students using PM. Material and methods: A random sample of 234 school students of middle and low-middle socioeconomic status, aged 9 to 14 years (53 percent women) were interviewed using PM about drug consumption. Results: The frequency of licit drug consumption during the last year was 29 percent and 15 percent during the last month (current consumption). The consumption of tobacco and alcohol was 20 percent and 18 percent respectively during the last year. The figures for the last month were 11 percent and 8 percent respectively. The beginning age for smoking and alcohol consumption were 11.1 ±1.5 and 11.3± 1.8 years respectively. The frequency of illicit drug consumption was 3.5 percent. Illicit drug users began licit drug consumption at earlier ages their non user peers. Conclusions: There is a high frequency of illicit drug consumption among school age children.

Adaptación y análisis psicométrico de un cuestionario para evaluar riesgos psicosociales en el trabajo en Chile: versión media del CoPsoQ / Adaptation and psychometric analysis of a questionnaire used to evaluate psychosocial risks in the workplace in Chile: CoPsoQ medium

Objetivo: Describir las propiedades psicométricas de un cuestionario para medir riesgos psicosociales en el trabajo, aplicado a una muestra chilena de trabajadores del rubro servicios. Material y Método: se comenzó con un proceso de adaptación semántica, para posteriormente aplicarlo a una nuestra de 1.087 personas (332 varones y 775 mujeres), con promedio de edad de 41,0 +/- 11,9 años. Resultados: Se eliminó 1 de las 73 preguntas del instrumento original. Se encontró buenas correlaciones ítem-test, una composición factorial similar a la original, buenos indicadores de consistencia interna y buenos indicadores de validez convergente (con el GHO-12). los mejores resultados se obtienen para las grandes dimensiones, más que para las subdimensiones específicas. Conclusiones: se trata de un cuestionario útil para la medición de factores de riesgos psicosociales en el trabajo en nuestro medio y se comporta de manera similar al instrumento original. Se recomienda su uso utilizando las grandes dimensiones.

Objective: Describe the psychometric properties of a questionnaire used to measure psychosocial risks at work, applying it to a sample of workers from the service sector in Chile. Materials and methods: We began with a process of semantic adaptation, in order to later apply it to a sample of 1,087 people (332 male and 775 female), with an average age of 41.0 +/- 11.9 years. Results: One of the 73 questions was eliminated from the original instrument. We found good item-test correlation, a factorial composition similar to the original, good indicators of internal consistency and good indicators of convergent validity (GHQ - 12). The best results were obtained for the main dimensions, more than for the specific sub-dimensions. Conclusions: This was shown to be a useful questionnaire for measuring psychosocial risk factors in the workplace in Chile and behaves similarly to the original instrument. Use of the main dimensions is recommended.

Efecto en la rata de los corticoides tópicos sobre los linfocitos circulantes / Effect in rats of the topical steroids on circulating lymphocytes

Los glucocorticoides tópicos se usan en diversas enfermedades inflamatorias dermatológicas, respiratorias, etc. Al igual que los glucocorticoides sistémicos pueden suprimir el eje hipotálamo-hipófisis-suprarrenal y producir efectos locales adversos. Por su uso en afecciones crónicas interesa conocer si los glucocorticoides tópicos tienen influencia sobre el número de linfocitos periféricos, lo que repercutiría en el sistema inmune. Se estudió el efecto de dos formas de corticoide de acción porlongada, dipropionato de betametasona, sobre los linfocitos circulantes y algunos órgano como la glándula suprarrenal y piel, en 46 ratas Wistar, aplicándose corticoide tópico en el 25 por ciento de la superficie corporal 2 veces al día a un grupo y sistémico por vía intramuscular por una sola vez en distintas dosis a otros 3 grupos. Después de realizar recuento de linfocitos los días 0,3 y 21, se observaron diferencias estadísticamente significativas en el número de linfocitos al día 3, alteración que revirtió en el análisis del recuento del día 21. En relación al uso de glucocorticoides sistémicos se observaron variaciones características de linfopenia y neutrofilia, que fueron más intensas a mayor dosis empleada. En análisis histopatológico se ralizó en el grupo de ratas con glucocorticoide tópico y sistémico a dosis baja y en las controles. Hubo cambios histopatológicos sólo a nivel de la corteza suprarrenal de las ratas tratadas con glucocorticoide sistémico a dosis baja y a nivel de piel para las ratas sometidasa tratamiento tópico