Risk factors for tuberculosis in older children and adolescents: a matched case-control study in Recife, Brazil.

BACKGROUND: Tuberculosis is a major disease worldwide and most research focus on risk factors for adults, although there is a marked adolescent peak in incidence. The objective of this study was to identify risk factors for tuberculosis in children aged 7 to 19. METHODS: A case control study matched by age with 169 cases and 477 controls. The study population consisted of adolescents and older children from Recife, Brazil. Cases were individuals diagnosed with tuberculosis in the control programme and controls were selected in the neighborhood of cases. Conditional logistic regression was used to identify risk factors. RESULTS: Cigarette smoking increased by 50% the risk of tuberculosis but that this was not statistically significant (OR = 1.6). Other risk factors were sleeping in the same house as a case of tuberculosis (OR = 31.6), living in a house with no piped water (OR = 7.7) (probably as a proxy for bad living conditions), illiteracy (OR = 3.7) and male sex (OR = 1.8). The increase in risk with living in houses with no piped water was much more marked in males. The proportion of cases of tuberculosis attributed to contact with someone with TB was 38% and to illiteracy, lack of piped water and smoking, 20%. CONCLUSION: Household contact with tuberculosis, social factors and male sex play the biggest role in determining risk of TB disease among children and adolescents in the study. We recommend further research on the relationship of cigarette smoking on tuberculosis in adolescents, and on whether the sex differentials are more marked in bad living conditions. Separate studies should be conducted in older children and in adolescents

Identificação de fatores de risco para morte por tétano em Pernambuco, Brasil: um estudo de caso-controle

A case-control study was conducted to identify risk factors for death from tetanus in the State of Pernambuco, Brazil. Information was obtained from medical records of 152 cases and 152 controls, admitted to the tetanus unit in the State University Hospital, in Recife, from 1990 to 1995. Variables were grouped in three different sets. Crude and adjusted odds ratios, p-values and 95% confidence intervals were estimated. Variables selected in the multivariate analysis in each set were controlled for the effect of those selected in the others. All factors related to the disease progression - incubation period, time elapsed between the occurrence of the first tetanus symptom and admission, and period of onset - showed a statistically significant association with death from tetanus. Similarly, signs and/or symptoms occurring on admission or in the following 24 hours (second set): reflex spasms, neck stiffness, respiratory signs/symptoms and respiratory failure requiring artificial ventilation (third set) were associated with death from tetanus even when adjusted for the effect of the others.Um estudo de caso-controle foi conduzido no Estado de Pernambuco, Brasil, para identificar fatores de risco para morte por tétano. As informações foram obtidas dos prontuários médicos de 152 casos e 152 controles, admitidos na Unidade de Tétano do Hospital Universitário Oswaldo Cruz, na cidade do Recife, de 1990 a 1995. As variáveis foram agrupadas em três diferentes conjuntos. Foram estimados os "odds ratios" brutos e ajustados, o intervalo de confiança de 95% e o valor de "p". As variáveis selecionadas na análise multivariada em cada conjunto, foram controladas para os efeitos daquelas selecionadas nos demais. Todos os fatores relacionados à progressão da doença - período de incubação, tempo decorrido entre o primeiro sintoma de tétano e a admissão no hospital, e período de progressão - mostraram uma associação estatisticamente significante com morte por tétano. De modo semelhante, o segundo conjunto de variáveis - sinais e/ou sintomas que ocorreram à admissão ou nas primeiras 24 horas: espasmos, rigidez de nuca, sinais e sintomas respiratórios - bem como as variáveis do terceiro conjunto - insuficiência respiratória que necessitou de respiração artificial foram associadas com morte por tétano, mesmo quando ajustadas com os efeitos das demais variáveis

Selection bias: neighbourhood controls and controls selected from those presenting to a Health Unit in a case control study of efficacy of BCG revaccination.

BACKGROUND: In most case control studies the hardest decision is the choice of the control group, as in the ideal control group the proportion exposed is the same as in the population that produced the cases. METHODS: A comparison of two control groups in a case control study of the efficacy of BCG revaccination. One group was selected from subjects presenting to the heath unit the case attended for routine prevention and care; the second group was selected from the neighbourhood of cases. All Health Units from which controls were selected offered BCG revaccination. Efficacy estimated in a randomized control trial of BCG revaccination was used to establish that the neighbourhood control group was the one that gave unbiased results. RESULTS: The proportion of controls with scars indicating BCG revaccination was higher among the control group selected from Health Unit attenders than among neighbourhood controls. This excess was not removed after control for social variables and history of exposure to tuberculosis, and appears to have resulted from the fact that people attending the Health Unit were more likely to have been revaccinated than neighbourhood controls, although we can not exclude an effect of other unmeasured variables. CONCLUSION: In this study, controls selected from people presenting to a Health Unit overrepresented exposure to BCG revaccination. Had the results from the HU attenders control group been accepted this would have resulted in overestimation of vaccine efficacy. When the exposure of interest is offered in a health facility, selection of controls from attenders at the facility may result in over representation of exposure in controls and selection bias

Migração e esquistossomose urbana. O caso de São Lourenço da Mata, Nordeste do Brasil

A population-based case-control design was used to investigate the association between migration, urbanisation and schistosomiasis in the Metropolitan Region of Recife, Northeast of Brazil. 1022 cases and 994 controls, aged 10 to 25, were selected. The natives and the migrants who come from endemic areas have a similar risk of infection. On the other hand, the risk of infection of migrants from nonendemic areas seems to be related with the time elapsed since their arrival in São Lourenço da Mata; those who have been living in that urban area for 5 or more years have a risk of infection similar to that of the natives. Those arriving in the metropolitan region of Recife mostly emigrate from "zona da mata" and "zona do agreste" in the state of Pernambuco. Due to the changes in the sugar agro-industry and to the increase in the area used for cattle grazing these workers were driven to villages and cities. The pattern of urbanisation created the conditions for the establishment of foci of transmission in São Lourenço da Mata.Um estudo de caso-controle de base populacional foi desenvolvido para estudar a associação entre migração, urbanização e esquistossomose na Região Metropolitana do Recife, Nordeste do Brasil. Foram selecionados 1022 casos e 994 controles no grupo etário de 10 a 25 anos. Observou-se que os nativos e os migrantes que são provenientes de áreas endêmicas tem um risco semelhante de infecção. Por outro lado, o risco de infecção em migrantes não originários de áreas endêmicas parece estar relacionado com o tempo decorrido desde sua chegada em São Lourenço da Mata; aqueles que estão morando nessa área urbana por um período igual ou superior a cinco anos tem um risco de infeção semelhante ao dos nativos. As mudanças na indústria agro-açucareira na Zona da Mata e a expansão das áreas de criação de gado no Agreste impeliram os trabalhadores rurais a se deslocar para vilarejos e cidades. O padrão de urbanização que ocorreu em São Loureço da Mata criou as condições propícias para que se estabelecessem focos de transmissão

Retratamento de hanseníase: estudo de caso-controle

OBJECTIVE: To assess risk factors for retreatment of leprosy patients. METHODS: A case-control study with patients from two reference care units in Recife, northeastern Brazil, in 2003. The case group included retreated patients (N=155) and the control group comprised those patients who were not retreated (N=155) matched by year of diagnosis and health care unit. Univariate and multivariate analyses were conducted to test the associations and odds ratios and related 95% confidence intervals were estimated. RESULTS: The following factors were found to be significantly associated (p; 1 (OR=6.43; 95% CI=1.67;24.74), therapeutic regimen consisting of sulfone monotherapy (OR=10; 95% CI=0.01;0.78) and reports of household contacts (OR=2.2; 95% CI=0.24;0.85). CONCLUSIONS: The study findings reinforce that the use of dapsone monotherapy should be discontinued, and highlight the need for epidemiological monitoring of specific groups of leprosy patients after treatment completion through periodical clinical and laboratory evaluation. Further studies to explore the association between final bacterial index and retreatment are strongly recommended.OBJETIVO: Analisar os fatores de risco para retratamento da hanseníase. MÉTODOS: Estudo de caso-controle com pacientes de duas unidades de referência para tratamento da hanseníase, em Recife, Pernambuco, no de 2003. O grupo de casos incluiu pacientes retratados (N=155) e foi comparado com o grupo controle (N=155), pacientes não retratados pareados por ano-diagnóstico e unidade de saúde. Para testar as associações foram realizadas análises uni e multivariadas, e calculados odds ratios com respectivos intervalos de confiança de 95%. RESULTADOS: Os seguintes fatores apresentaram associação estatisticamente significante (p; 1 (OR=6,43; IC 95%:1,67;24,74); tratamento com a monoterapia sulfônica (OR=10; IC 95%: 0,01;0,78); relato de contato intradomiciliar com portadores de hanseníase (OR=2,2; IC 95%:0,24;0,85). CONCLUSÕES: Os resultados reforçam o desuso da monoterapia sulfônica e apontam a necessidade de se monitorizar grupos específicos de pacientes após alta terapêutica, através do acompanhamento clínico e laboratorial periódico. Recomenda-se a realização de novos estudos para explorar a associação entre o índice baciloscópico final e retratamento

Hiperatividade simpática e arritmias no tétano: análise eletrocardiográfica

As a result of the advances in the control of pulmonary insufficiency in tetanus, the cardiovascular system has increasingly been shown to be a determining factor in morbidity and mortality but detailed knowledge of the cardiovascular complications in tetanus is scanty. The 24h-Holter was carried out in order to detect arrhythmias and sympathetic overactivity in 38 tetanus patients admitted to an ICU. The SDNN Index (standard deviation from the normal R-to-R intervals), was useful in detecting adrenergic tonus, and ranged from 64.1 ± 27 in the more severe forms of tetanus to 125 ± 69 in the milder ones. Sympathetic overactivity occurred in 86.2% of the more severe forms of the disease, but was also detected in 33% of the milder forms. Half the patients had their sympathetic overactivity detected only by the Holter. The most frequent arrhythmias were isolated supraventricular (55.2%) and ventricular (39.4%) extrasystoles. There was no association of the arrhythmias with the clinical form of tetanus or with the presence of sympathetic overactivity. The present study demonstrated that major cardiovascular dysfunction, particularly sympathetic overactivity, occurs in all forms of tetanus, even in the milder ones. This has not been effectively detected with traditional monitoring in ICU and may not be properly treated.Com os avanços no controle da insuficiência respiratória no tétano, o sistema cardiovascular tem participado de forma crescente na morbidade e mortalidade da doença, mas o conhecimento dessas complicações é escasso. No intuito de detectar arritmias e hiperatividade simpática, o holter de 24 h foi utilizado em 38 pacientes com tétano admitidos numa UTI de doenças infecciosas. O índice SDNN (desvio standard dos intervalos normais R-a-R), foi útil na detecção do tônus adrenérgico, e variou de 64,1 ± 27 nas formas mais severas de tétano a 125 ± 69 nas formas mais leves. Hiperatividade simpática ocorreu em 86,2% das formas mais severas da doença, mas também foi identificada em 33% das formas leves. Cerca da metade dos pacientes tiveram sua hiperatividade simpática detectada apenas pelo Holter. As arritmias mais freqüentes foram extrassístoles isoladas, do tipo supraventriculares (55,2%) ou ventriculares (39,4%). Não houve associação das arritmias com a forma clínica do tétano ou com a presença de hiperatividade simpática. O presente estudo demonstrou que importantes alterações cardiovasculares, particularmente a hiperatividade simpática, ocorrem em todas as formas de tétano, mesmo as mais leves. Estas alterações não estão sendo detectadas pelos métodos tradicionais de monitorização em UTI, podendo resultar em falhas na abordagem terapêutica