Determinantes biopsicosociales de depresión en pacientes atendidos en Centros de Atención Primaria de Concepción, Chile / Biopsychosocial depression determinants in patients treated in Primary Health Centers at Concepción, Chile

Introducción: Los factores de riesgo asociados a la depresión han sido estudiados ampliamente, pero no se dispone de estudios prospectivos sobre factores que predigan la incidencia de depresión en personas sanas. Tampoco se dispone de una ecuación predictiva que incorpore factores genéticos. Método: Estudio de cohorte, prospectivo con evaluaciones en línea base y a los doce meses, sobre una muestra aleatoria de consultantes en centros de atención primaria de la Provincia de Concepción, Chile (n = 1.596). Se midieron 8 factores psicosociales y se realizó genotificación de los polimorfismos para la monoaminooxidasa A, la uMAO, y para la región transportadora del gen del transportador de serotonina, el 5-HTTLPR, gen SLC6A4 del cromosoma 17, como factores genéticos y la variable de resultado fue la presencia/ausencia de depresión a los 12 meses de seguimiento. Se empleó regresión logística binaria. Resultados: Las dos variables genéticas no muestran relación estadísticamente significativa con la variable depresión a los 12 meses de seguimiento. Las variables sexo, nivel educacional, satisfacción con las condiciones de vida, antecedente personal de depresión, autopercepción de la salud física y de la salud mental y satisfacción con las relación de pareja se relacionan con la aparición de depresión en el seguimiento. Conclusiones: Los resultados permitirán identificar personas vulnerables entre los consultantes de atención primaria que podrían participar de programas preventivos. El estudio de otros genes será necesario para mejorar la capacidad predictiva del modelo.

Introduction: Riskfactors associated to depression have been extensively studied, though there is a lack ofprospective studies on factors thatpredict the incidence of depression in healthy people. There is not a predictive equation that incorporates genetic factors is not available. Method: A cohort study, prospective, with baseline assessments at 12 months was carried out on a random sample of attendees in primary care centers form the Concepción Province, Chile (n = 1,596). Eight psychosocial factors were measured and the genotyping of the uMAO and 5-HTTLPR in SLC6A4 as genetic factors polymorphisms was also carried out. The outcome variable was the presence/absence of depression at 12 months follow-up. A predictive model for depression was obtained by means of analyses of binary logistic regression. Results: Genetic variables have no statistically significant relation with the variable depression at 12 months follow up. Variables such as gender, educational level, satisfaction with living conditions, personal background ofdepression, selfperception ofboth physical and mental health and satisfaction with relationship are related to the onset ofdepression in the follow up. Conclusions: Outcomes will allow identifying vulnerable people among the primary care attendees, who could participate in prevention programs. The study offurther genes will be necessary in order to improve the predictive capacity of the model.

Identification and Characterization of Human Genes Targeted by Natural Selection

The human genome has evolved as a consequence of evolutionary forces, such as natural selection. In this study, we investigated natural selection on the human genes by comparing the numbers of nonsynonymous(NS) and synonymous (S) mutations in individual genes. We initially collected all coding SNP data of all human genes from the public dbSNP. Among the human genes, we selected 3 different selection groups of genes: positively selected genes (NS/S > or = 3), negatively selected genes (NS/S < or = 1/3) and neutral selection genes (0.9 < NS/S < 1.1). We characterized human genes targeted by natural selection. Negatively selected human genes were markedly associated with disease occurrence, but not positively selected genes. Interestingly, positively selected genes displayed an increase in potentially deleterious nonsynonymous SNPs with an increased frequency of tryptophan and tyrosine residues, suggesting a correlation with protective effects against human disease. Furthermore, our nonsynonymous/synonymous ratio data imply that specific human genes, such as ALMS1 and SPTBN5 genes, are differentially selected among distinct populations. We confirmed that inferences of natural selection using the NS/S ratio can be used extensively to identify functional genes selected during the evolutionary adaptation process.