SU80 - LEUKOCYTE TELOMERE LENGTH ANALYSIS IN CHILDREN AND ADOLESCENTS AT RISK OF DEVELOPING MENTAL DISORDERS

Abstract

Background Telomeres are DNA-protein complexes that constitutes the terminal portions of chromosomes, providing them stability and protection and go through physiological shortening along cell cycles. However, this shortening can be intensified by cytokines, stress hormones and oxidation exposition. After reaching a critical length, telomere shortening leads to senescence or apoptosis. Telomere Length (TL) is altered in cancer, diabetes, cardiovascular and autoimmune diseases. Additionally, TL has been described as related to psychiatric disorders like Major Depressive Disorders (MDD), Bipolar Disorder (BD) and Schizophrenia (SCZ). TL was found to have a dose-dependent association with stress in childhood, however it is not clear whether this shortening can be used as a diagnosis and progression biomarker. This study investigated the association between leucocyte TL and psychiatric diagnosis, psychiatric symptoms and child maltreatment and also verified association of TL with age and gender. Methods The 559 participants of this study were a subsample of the High Risk Cohort (HRC) Study for Psychiatric Disorders in Childhood, a large prospective community school-based study in Brazil. Blood sample were collected 6 to 8 months after parent interview, in which participants were assessed using Development and Well-Being Assessment (DAWBA) to evaluate psychiatric diagnosis according to the DSM-IV. Psychopathology was assessed by the Child Behavior Checklist (CBCL). DSM-oriented scaled were used and grouped in Internalizing and Externalizing groups of symptoms. Child Maltreatment (CM) measure was based on four questions answered by parents and children about the history of physical abuse, neglect, emotional maltreatment and sexual abuse. The 394 children and adolescents with no DSM-IV disorder in DAWBA assessment composed the healthy control group. Leucocyte TL measurement was performed by quantitative qPCR. Study population description as well as CBCL and CM means between case and controls were analyzed by Student's T test. Association of TL with gender and age or psychiatric symptoms was analyzed by generalized linear model (GLzM). Results In this study population, no association between TL and age or gender was observed. Equally, absence of distress, fear and behavior disorders showed no association with TL. The weak positive correlation (r2=0,01) between externalizing CBCL and TL obtained was proved not significant after Bonferroni correction. And no associations between TL and CM or between CM and gender were shown. However, after sorting the cohort by gender, a negative correlation (p=0,014; OR=0,938; IC 95%=0,891 – 0,987; r2=0,021) between TL and CM were observed in boys. Discussion This was a cross sectional study which does a momentary analysis of the TL and the mental state of individuals. The number of participants and the complete psychiatric framework brings to it a strong statistical power and although there is no association between TL and age, gender, CBCL, absence of distress, fear and behavior disorders were observed, a correlation between TL and CM was found only in boys but not in girls. The high levels of estrogen in girls might act as a protective factor indirectly influencing TL in this gender. Thus, this study points out that males who experienced more early life traumas seem to have shorter TL.