Alterações de volumes corticais e subcorticais em usuários de crack

além do aumento da prevalência do seu consumo nas últimas décadas, especialmente no Brasil. Os resultados de pesquisa em neuroimagem nesse campo são sobre alterações do uso de cocaína, substância semelhante ao crack, mas este possui diversas particularidades que, clinicamente, o tornam potencialmente mais agressivo e danoso ao organismo. Não se sabe se tais semelhanças também são compartilhadas no que diz respeito a modificações de volumes cerebrais. Os transtornos aditivos, de modo geral, afetam o sistema de recompensa, mas também circuitos cerebrais envolvidos com condicionamento, motivação e função executiva (controle inibitório, atribuição de valores e tomada de decisão). As drogas representam um complexo estressor para o organismo. À medida em que o uso ocasional se torna abusivo e crônico, há recrutamento duradouro dos mecanismos regulatórios do cérebro, modificando eixos fisiológicos de homeostase. Em 2011, Volkow et al propuseram um modelo de alteração do neurocircuito cerebral em um cérebro adicto em comparação com o funcionamento de um cérebro não-adicto. O objetivo desta tese foi investigar as alterações de volume cerebral, corticais e subcorticais, em usuários de crack, bem como avaliar a associação destes achados com o modelo de três estágios proposto por Volkow e Koob. Método: estudo de caso-controle, com amostra de 15 usuários de crack e 15 controles saudáveis, pareados por gênero, idade, escolaridade e lateralidade, recrutados na Unidade de Adição da Unidade Álvaro Alvim do Hospital de Clínicas de Porto Alegre (HCPA). Realizaram exame de Ressonância Magnética Nuclear após pelo menos 15 dias de desintoxicação. Foram excluídas comorbidades neurológicas, inflamatórias, cardiovasculares ou 8 sistêmicas. Os volumes das estruturas corticais e subcorticais foram determinados usando o programa Freesurfer v5.3. Resultados: Artigo 1. Os dois grupos (casos e controles) não diferiram em relação à idade, gênero (todos os indivíduos eram do sexo masculino), educação, estado civil e ocupação principal. Todas as variáveis na amostra tiveram distribuição normal. Os usuários de crack tiveram menores volumes no núcleo accumbens esquerdo (t = 3,604, df = 28, p = 0,001) em relação aos pacientes. Os volumes do núcleo accumbens direito também foram menores nos pacientes e apresentaram diferenças significativas entre os grupos (t = 2,098, df = 28, p = 0,045). Os grupos não diferiram em relação aos volumes intracranianos (p = 0,514). Artigo 2. Os pacientes tiveram volumes de amígdala menores do que os controles, (F (1,28) = 5,885, p = 0,023). O córtex pré-frontal dorsolateral (dLPFC) também foi menor entre os usuários de crack quando comparado aos controles (F (1,28) = 5,447, p = 0,027). Não houve diferença entre os volumes do córtex orbitofrontal (F (1,28) = 2,917, p = 0,100) e ínsula (F (1,28) = 2,815, p = 0,105) entre os grupos. Houve uma tendência à significância entre os grupos no córtex cingulado Anterior (F (1,28) = 3,992, p = 0,056) e hipocampo (F (1,28) = 3,535, p = 0,071). Entre os casos, todos os volumes estudados não se correlacionaram com variáveis clínicas de gravidade (anos de dependência de crack, idade de primeiro uso, número diário de pedras de crack , e duração da abstinência). Os grupos não diferiram em relação à idade, educação, estado civil e ocupação. Todos eram homens e destros. Conclusões: Os resultados deste trabalho mostram que a população de usuários de crack possui volumes cerebrais reduzidos em regiões corticais e subcorticais. Estas regiões estão implicadas nos sistemas de recompensa, de motivação, de funções executivas e memória, e estão de acordo com os estágios propostos por Volkow e Koob e com as teorias de neuroprogressão das adições. Desta forma, tais achados podem auxiliar na compreensão da fisiopatologia do Transtorno por Uso de Crack e corroboram os déficits cognitivos já evidenciados clinicamente nesta população. Entretanto, ressalta-se a importância de estudos longitudinais com o objetivo de avaliar a causalidade e reversibilidade destas alterações, a fim de nortear futuras intervenções terapêuticas em um grupo tão complexo e grave.Introduction: Crack-cocaine consumption has been a major concern due to its geographical expansion, followed by a recent increase in its prevalence especially in Brazil. Neuroimaging research currently available is limited to cocaine use, a precursor of crackcocaine. Clinically, crack-cocaine has several peculiarities that make it potentially more aggressive and damaging to the body when compared to cocaine. It is not known whether such similarities are also shared regarding changes in brain volumes. Addictive disorders, in general, affect the reward system, but also brain circuits involved with conditioning, motivation, and executive function (i.e. inhibitory control and decision making). Drugs represent a complex stressor for the body. As occasional use becomes abusive and chronic, there is a lasting recruitment of the regulatory mechanisms of the brain, modifying physiological axes of homeostasis. In 2011, Volkow et al proposed a model of brain neurocircuit alteration of addicted brains compared to the functioning of a non-addicted brain. In this sense, the aim of this thesis was to investigate changes in cortical and subcortical brain volumes in crack-cocaine users, as well as to evaluate the association of these findings with the three-stage model proposed by Volkow and Koob. Method: This is a case-control study, with a sample of 15 crack-cocaine users and 15 healthy controls, matched by gender, age, education and handedness, recruited at the Álvaro Alvim Addiction Unit of the Hospital de Clinicas de Porto Alegre (HCPA). They underwent structural MRI after at least 15 days of detoxification. Neurological, inflammatory, 11 cardiovascular or systemic comorbidities were excluded. The volumes of the cortical and subcortical structures were determined using the Freesurfer v5.3 program. Results: Article 1. The two groups (patients and controls) did not differ regarding age, gender (all individuals were male), education, marital status and occupation. Controls had higher volumes in the left nucleus accumbens (t = 3.604, df = 28, p = 0.001) compared to patients. Right nucleus accumbens volumes were also higher in controls and showed significant differences between groups (t = 2.098, df = 28, p = 0.045). Groups did not differ in relation to intracranial volumes (p = 0.514). Article 2. Patients had lower amygdala volumes than controls (F (1,28) = 5.885, p = 0.023). The dorsolateral prefrontal cortex (DLPFC) volumes were reduced among crack-cocaine users when compared to controls (F (1,28) = 5.447, p = 0.027). No difference was found between groups in Orbitofrontal cortex (F (1,28) = 2.917, p = 0.100) and insula (F (1,28) = 2.815, p = 0.105) . There was a trend toward significance between groups in the anterior cingulate cortex (F (1,28) = 3.992, p = 0.056) and hippocampus (F (1,28) = 3.535, p = 0.071). Among patients, volumes of all structures assessed were not correlated with clinical variables of severity (years of crack dependence, age of first use, daily number of crack-cocaine rocks, and duration of abstinence). Groups did not differ regarding age, education, marital status and occupation. They were all men and right-handed. Conclusions: Our findings show that the population of crack users had smaller cerebral volumes in cortical and also subcortical regions compared to matched controls. These regions are implicated in reward systems, motivation, executive functions, and memory; and are in line with the theories of neoruprogression in substance use disorders. Thus, our findings may help in 12 understanding the pathophysiology of Crack-cocaine Use Disorder and it is in agreement with the cognitive deficits already clinically evidenced in this population. However, the importance of longitudinal studies evaluating the causality and reversibility of these alterations, in order to guide future therapeutic interventions in such a complex and severe group, is emphasized

DPP9 is a novel component of the N-end rule pathway targeting the tyrosine kinase Syk.

The aminopeptidase DPP9 removes dipeptides from N-termini of substrates having a proline or alanine in second position. Although linked to several pathways including cell survival and metabolism, the molecular mechanisms underlying these outcomes are poorly understood. We identified a novel interaction of DPP9 with Filamin A, which recruits DPP9 to Syk, a central kinase in B-cell signalling. Syk signalling can be terminated by degradation, requiring the ubiquitin E3 ligase Cbl. We show that DPP9 cleaves Syk to produce a neo N-terminus with serine in position 1. Pulse-chases combined with mutagenesis studies reveal that Ser1 strongly influences Syk stability. Furthermore, DPP9 silencing reduces Cbl interaction with Syk, suggesting that DPP9 processing is a prerequisite for Syk ubiquitination. Consistently, DPP9 inhibition stabilizes Syk, thereby modulating Syk signalling. Taken together, we demonstrate DPP9 as a negative regulator of Syk and conclude that DPP9 is a novel integral aminopeptidase of the N-end rule pathway

Childhood trauma and resilience : vulnerabilities to develop crack/cocaine dependence

Background: Crack cocaine dependence is a health problem of epidemic proportions and there is lack of evidence concerning vulnerability factors that could lead to crack cocaine use. The aim of this study is to investigate characteristics of resilience in a group of crack cocaine users and its association with childhood trauma and PTSD. Method: This is a case-control study in which we evaluated 218 crack cocaine inpatients users and 215 healthy controls, recruited from the capital city of the southern State of Brazil. Childhood Trauma was evaluated with the Childhood Trauma Questionnaire; resilience was evaluated with the Resilience Scale; and post-traumatic stress disorder (PTSD) was evaluated with the Mini-International Neuropsychiatric Interview. Results: Childhood trauma was significantly higher among crack cocaine users in all trauma domains (p<0.001), except for sexual abuse. Most resilience scores was lower among crack cocaine users (p<0.01). Having higher scores of childhood trauma and lower scores of resilience increase the odds to become a crack cocaine user (p<0.001), despite the diagnosis of PTSD. Discussion: Childhood trauma appears to be a risk factor to become a crack cocaine user while resilience features may be a protection factor. To understand factors of vulnerabilities in this population is important for the development of more efficacious treatment and preventive strategies

Effects of childhood trauma on BDNF and TBARS during crack-cocaine withdrawal

Objective: To evaluate the association between childhood trauma (CT) and serum levels of brainderived neurotrophic factor (BDNF) and thiobarbituric acid-reactive substances (TBARS) during crackcocaine withdrawal. Method: Thirty-three male crack-cocaine users were recruited at admission to a public addiction treatment unit. Serum BDNF and TBARS levels were evaluated at intake and discharge. Information about drug use was assessed by the Addiction Severity Index-6th Version (ASI-6); CT was reported throughout the Childhood Trauma Questionnaire (CTQ). CTQ scores were calculated based on a latent analysis model that divided the sample into low-, medium-, and high-level trauma groups. Results: There was a significant increase in BDNF levels from admission to discharge, which did not differ across CT subgroups. For TBARS levels, we found a significant time vs. trauma interaction (F2,28 = 6.357, p = 0.005,Zp 2 = 0.312). In participants with low trauma level, TBARS decreased, while in those with a high trauma level, TBARS increased during early withdrawal. Conclusion: TBARS levels showed opposite patterns of change in crack-cocaine withdrawal according to baseline CT. These results suggest that CT could be associated with more severe neurological impairment during withdrawal

Prevalência e tendências temporais de transtornos mentais necessitando de tratamento de internação na cidade de Porto Alegre: Um estudo de toda a cidade incluindo todas as internações por motivo de saúde mental no sistema público de 2013-2017

Objectives: To investigate the 5-year prevalence of patients admitted to public inpatient care units due to a mental disorder, stratifying them by age group and diagnosis, and to assess trends of admissions over this time period in Porto Alegre. Methods: All admissions to the public mental health care system regulated by the city-owned electronic system Administração Geral dos Hospitais (AGHOS) were included in the analysis. The total population size was obtained by estimations of Fundação de Economia e Estatística (FEE). General information about 5-year prevalence of inpatient admissions, time-series trends e prevalence by age groups and diagnosis were presented. Results: There were 32,608 admissions over the 5-year period analyzed. The overall prevalence of patients was 1.62% among the total population, 0.01% among children, 1.12% among adolescents, 2.28% among adults and 0.93% among the elderly. The most common diagnosis was drug-related, followed by mood, alcohol-related and psychotic disorders. There was a linear trend showing an increase in the number of admissions from 2013 to the midst of 2014, which dropped in 2015. Conclusions: Admissions due to mental disorders are relatively common, mainly among adults and related to drug use and mood disorders. Time trends varied slightly over the 5 years. Prevalence rates in real-world settings might be useful for policymakers interested in planning the public mental health system in large Brazilian cities

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to &lt;90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], &gt;300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of &lt;15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P&lt;0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P&lt;0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

Alterações de volumes corticais e subcorticais em usuários de crack

além do aumento da prevalência do seu consumo nas últimas décadas, especialmente no Brasil. Os resultados de pesquisa em neuroimagem nesse campo são sobre alterações do uso de cocaína, substância semelhante ao crack, mas este possui diversas particularidades que, clinicamente, o tornam potencialmente mais agressivo e danoso ao organismo. Não se sabe se tais semelhanças também são compartilhadas no que diz respeito a modificações de volumes cerebrais. Os transtornos aditivos, de modo geral, afetam o sistema de recompensa, mas também circuitos cerebrais envolvidos com condicionamento, motivação e função executiva (controle inibitório, atribuição de valores e tomada de decisão). As drogas representam um complexo estressor para o organismo. À medida em que o uso ocasional se torna abusivo e crônico, há recrutamento duradouro dos mecanismos regulatórios do cérebro, modificando eixos fisiológicos de homeostase. Em 2011, Volkow et al propuseram um modelo de alteração do neurocircuito cerebral em um cérebro adicto em comparação com o funcionamento de um cérebro não-adicto. O objetivo desta tese foi investigar as alterações de volume cerebral, corticais e subcorticais, em usuários de crack, bem como avaliar a associação destes achados com o modelo de três estágios proposto por Volkow e Koob. Método: estudo de caso-controle, com amostra de 15 usuários de crack e 15 controles saudáveis, pareados por gênero, idade, escolaridade e lateralidade, recrutados na Unidade de Adição da Unidade Álvaro Alvim do Hospital de Clínicas de Porto Alegre (HCPA). Realizaram exame de Ressonância Magnética Nuclear após pelo menos 15 dias de desintoxicação. Foram excluídas comorbidades neurológicas, inflamatórias, cardiovasculares ou 8 sistêmicas. Os volumes das estruturas corticais e subcorticais foram determinados usando o programa Freesurfer v5.3. Resultados: Artigo 1. Os dois grupos (casos e controles) não diferiram em relação à idade, gênero (todos os indivíduos eram do sexo masculino), educação, estado civil e ocupação principal. Todas as variáveis na amostra tiveram distribuição normal. Os usuários de crack tiveram menores volumes no núcleo accumbens esquerdo (t = 3,604, df = 28, p = 0,001) em relação aos pacientes. Os volumes do núcleo accumbens direito também foram menores nos pacientes e apresentaram diferenças significativas entre os grupos (t = 2,098, df = 28, p = 0,045). Os grupos não diferiram em relação aos volumes intracranianos (p = 0,514). Artigo 2. Os pacientes tiveram volumes de amígdala menores do que os controles, (F (1,28) = 5,885, p = 0,023). O córtex pré-frontal dorsolateral (dLPFC) também foi menor entre os usuários de crack quando comparado aos controles (F (1,28) = 5,447, p = 0,027). Não houve diferença entre os volumes do córtex orbitofrontal (F (1,28) = 2,917, p = 0,100) e ínsula (F (1,28) = 2,815, p = 0,105) entre os grupos. Houve uma tendência à significância entre os grupos no córtex cingulado Anterior (F (1,28) = 3,992, p = 0,056) e hipocampo (F (1,28) = 3,535, p = 0,071). Entre os casos, todos os volumes estudados não se correlacionaram com variáveis clínicas de gravidade (anos de dependência de crack, idade de primeiro uso, número diário de pedras de crack , e duração da abstinência). Os grupos não diferiram em relação à idade, educação, estado civil e ocupação. Todos eram homens e destros. Conclusões: Os resultados deste trabalho mostram que a população de usuários de crack possui volumes cerebrais reduzidos em regiões corticais e subcorticais. Estas regiões estão implicadas nos sistemas de recompensa, de motivação, de funções executivas e memória, e estão de acordo com os estágios propostos por Volkow e Koob e com as teorias de neuroprogressão das adições. Desta forma, tais achados podem auxiliar na compreensão da fisiopatologia do Transtorno por Uso de Crack e corroboram os déficits cognitivos já evidenciados clinicamente nesta população. Entretanto, ressalta-se a importância de estudos longitudinais com o objetivo de avaliar a causalidade e reversibilidade destas alterações, a fim de nortear futuras intervenções terapêuticas em um grupo tão complexo e grave.Introduction: Crack-cocaine consumption has been a major concern due to its geographical expansion, followed by a recent increase in its prevalence especially in Brazil. Neuroimaging research currently available is limited to cocaine use, a precursor of crackcocaine. Clinically, crack-cocaine has several peculiarities that make it potentially more aggressive and damaging to the body when compared to cocaine. It is not known whether such similarities are also shared regarding changes in brain volumes. Addictive disorders, in general, affect the reward system, but also brain circuits involved with conditioning, motivation, and executive function (i.e. inhibitory control and decision making). Drugs represent a complex stressor for the body. As occasional use becomes abusive and chronic, there is a lasting recruitment of the regulatory mechanisms of the brain, modifying physiological axes of homeostasis. In 2011, Volkow et al proposed a model of brain neurocircuit alteration of addicted brains compared to the functioning of a non-addicted brain. In this sense, the aim of this thesis was to investigate changes in cortical and subcortical brain volumes in crack-cocaine users, as well as to evaluate the association of these findings with the three-stage model proposed by Volkow and Koob. Method: This is a case-control study, with a sample of 15 crack-cocaine users and 15 healthy controls, matched by gender, age, education and handedness, recruited at the Álvaro Alvim Addiction Unit of the Hospital de Clinicas de Porto Alegre (HCPA). They underwent structural MRI after at least 15 days of detoxification. Neurological, inflammatory, 11 cardiovascular or systemic comorbidities were excluded. The volumes of the cortical and subcortical structures were determined using the Freesurfer v5.3 program. Results: Article 1. The two groups (patients and controls) did not differ regarding age, gender (all individuals were male), education, marital status and occupation. Controls had higher volumes in the left nucleus accumbens (t = 3.604, df = 28, p = 0.001) compared to patients. Right nucleus accumbens volumes were also higher in controls and showed significant differences between groups (t = 2.098, df = 28, p = 0.045). Groups did not differ in relation to intracranial volumes (p = 0.514). Article 2. Patients had lower amygdala volumes than controls (F (1,28) = 5.885, p = 0.023). The dorsolateral prefrontal cortex (DLPFC) volumes were reduced among crack-cocaine users when compared to controls (F (1,28) = 5.447, p = 0.027). No difference was found between groups in Orbitofrontal cortex (F (1,28) = 2.917, p = 0.100) and insula (F (1,28) = 2.815, p = 0.105) . There was a trend toward significance between groups in the anterior cingulate cortex (F (1,28) = 3.992, p = 0.056) and hippocampus (F (1,28) = 3.535, p = 0.071). Among patients, volumes of all structures assessed were not correlated with clinical variables of severity (years of crack dependence, age of first use, daily number of crack-cocaine rocks, and duration of abstinence). Groups did not differ regarding age, education, marital status and occupation. They were all men and right-handed. Conclusions: Our findings show that the population of crack users had smaller cerebral volumes in cortical and also subcortical regions compared to matched controls. These regions are implicated in reward systems, motivation, executive functions, and memory; and are in line with the theories of neoruprogression in substance use disorders. Thus, our findings may help in 12 understanding the pathophysiology of Crack-cocaine Use Disorder and it is in agreement with the cognitive deficits already clinically evidenced in this population. However, the importance of longitudinal studies evaluating the causality and reversibility of these alterations, in order to guide future therapeutic interventions in such a complex and severe group, is emphasized

Scenario planning for climate change adaptation for natural resource management: Insights from the Australian East Coast Cluster

Natural resources and inherent ecosystem services have long been under pressure from unsustainable exploitation further exacerbated by climate change impacts. Managing natural resources in the Australian context is also a complex task because it involves a raft of stakeholders subjected to ongoing institutional changes and reductions in funding for programme implementation. This paper explores the use of scenario planning as a suitable tool to deal with the uncertainty and complexity inherent to natural resource management. Specifically, it reports on the development and application of explorative scenarios (multiple plausible futures) involving six natural resource management organisations and their communities of practice operating along the East Coast of Australia. Scenarios were developed based on two key drivers of change, namely: maturing approach to natural resource management; and community driven climate change action, to test the robustness and flexibility of a suite of existing strategies, policies and targets. Findings indicate that explorative scenarios were useful in the identification of strategies that may result in perverse or negative impacts under different futures; guide selection of different approaches in response to unexpected events; encourage a forward-looking approach rather than relying on past experiences only; create flexible, robust strategies that are better able to deal with shocks and surprises; provide participating policy owners with an opportunity to consider future contexts for their policies to play out in; and, ascertain a range of possible pathways to achieve a vision or goals depending on changed circumstances

Prevalência de erros refrativos em escolares da primeira série do ensino fundamental da região Nordeste do Rio Grande do Sul Prevalence of refractive errors in first grade school children of elementary schools of Northeast region of the Rio Grande do Sul State, Brazil

OBJETIVOS: Descrever e analisar a prevalência de erros refrativos em estudantes de primeira série das escolas estaduais de Passo Fundo, cidade pólo da região Nordeste do Rio Grande do Sul. MÉTODOS: Estudo transversal de 1608 alunos da primeira série do ensino fundamental de 26 escolas estaduais de Passo Fundo, atendidas em 2004. Os dados foram coletados no CEAE (Centro Especializado de Assistência ao Educando), que fez a triagem nas escolas, e no serviço especializado, para onde foram encaminhados aqueles com testes alterados. RESULTADOS: Da amostra total, 172 (10,88%) apresentaram baixa de acuidade visual ou algum sintoma de problema visual, recebendo encaminhamento para atendimento oftalmológico. Apenas 88 (51,16%) dos encaminhados compareceram à consulta. A média de idade foi de 7,10 anos (DP= 1,38). Entre as crianças examinadas, 70,46% possuíam algum erro refracional, sendo a hipermetropia e o astigmatismo os mais comuns (encontrado em 45,45% e 10,23% dos alunos examinados, respectivamente). A miopia foi o erro refracional menos prevalente, presente em 10,23% dos escolares atendidos. CONCLUSÃO: O estudo mostrou prevalência de 3,92% de erros refrativos na população de escolares estudada, embora a abstenção elevada possa estar subestimando esse percentual. Percebe-se a necessidade da realização de programas que enfoquem uma maior adesão dos alunos ao encaminhamento, na tentativa de evitar o não diagnóstico de problemas oculares facilmente tratáveis na infância.OBJECTIVES: To describe and analyze the prevalence of refractive errors among first-graders in state schools of Passo Fundo, main city of the northeast region of Rio Grande do Sul State. METHODS: Cross-sectional study of 1608 first-graders in 26 elementary state schools of Passo Fundo, evaluated in 2004. The data were collected by the CEAE (Specialized Center for Student Assistance), which was in charge of the screening at the schools, and by the specialized service, to which those students with abnormal test results were referred. RESULTS: 172 (10.88%) of the sampled individuals showed poor visual acuity or some symptoms of visual disorders, and were then referred for specialized ophthalmic examination. However, only 88 (51.16%) of the referred patients turned up for the examination. The mean age was 7.10 years (DP= 1,38). Among all evaluated, 70,46% of them had some refractive disorder, of wich hyperopia and astigmatism were the most frequent ones, having been reported in 45.45% and 10.23% of the children, respectively. The myopia were the less frequent refractive disorder, reported in 10,23% of the school children who turned up for examination. CONCLUSION: The study showed a prevalence of 3,92% of refractive errors in the population studied, although the high abstention can be underestimating this percentage. We can realize, from that on, the need of the creation of programs focused in a bigger adhesion of the students to the reference to a specialized service, in the attempt of avoiding the lack of diagnosis of easily treatable disorders in childhood