[Silicosis among semiprecious gem cutters in Joaquim Felício, Minas Gerais State, Brazil]. / A silicose e o perfil dos lapidários de pedras semipreciosas em Joaquim Felício, Minas Gerais, Brasil.

A cross-sectional study was performed to determine the prevalence of silicosis among semiprecious gem cutters (n=70) and describe their clinical, epidemiological, and occupational profiles in Joaquim Felício, Minas Gerais State, Brazil, from April to December 2002. Occupational history was used with a respiratory questionnaire, chest x-ray, and spirometry. Silicosis prevalence was 7.1%. All affected individuals were men, with a mean age of 21.5 and mean exposure to silica of 7.1 years. All belonged to the informal economy and had been working at small and rudimentary workshops, using improvised lathes, with intense exposure to silica dust. According to the ILO Radiological Classification, four of the five cases of silicosis were classified as grade 1 and one as grade 3. Silicosis among gem cutters constitutes a serious public health problem that requires efforts to minimize risk through work by multidisciplinary teams from government agencies and nongovernmental organizations, with active participation by the workers themselves.

Presentation of congenital heart disease diagnosed at birth: analysis of 29,770 newborn infants.

OBJECTIVE: To estimate the prevalence rate and study the clinical presentation and associated factors of congenital heart diseases diagnosed at birth between August 1990 and December 2003, at the Maternity Unit of the Hospital das Clínicas, Universidade Federal de Minas Gerais, Brazil. METHODS: A retrospective, database driven study, part of the Latin-American collaborative study of congenital malformations. Records were reviewed on all live born (LB) and stillborn (SB) infants with congenital heart diseases diagnosed by postnatal echocardiogram or by autopsy. Data on birth weight, sex, age and parity were collected for the LB and studied for associations. The statistical analysis employed Pearson's chi-square test and multinomial logistic regression. RESULTS: During the period studied there were 29,770 births (28,915 LB and 855 SB). The prevalence of heart disease among the LB was 9.58:1,000 (277/28,915) while among SB the rate was 87.72:1,000 (75/855). Heart disease occurred isolated in 37.2% of LB cases and 18.7% of SB cases; was associated with anomalies of other organs and systems, but without a syndromic diagnosis in 31.4% of LB cases and 48.0% of SB cases; and in 23.1% of the LB cases and 32.0% of the SB cases the heart disease was a feature of a syndrome. Multivariate analysis demonstrated an association between heart disease and birth weight or= 35 years and heart disease in syndromic heart disease and between female sex and isolated heart disease. CONCLUSIONS: It was found a high prevalence, which is an alert to the medical significance of heart disease. There was association between birth weight

Hearing loss in congenital toxoplasmosis detected by newborn screening.

UNLABELLED: Congenital toxoplasmosis may cause sensorineural deficit in up to 20% of the patients and proper treatment in the first year improves prognosis. In Brazil, this infections impact on hearing impairment is unknown. AIM: To evaluate hearing of newborns with congenital toxoplasmosis identified by the newborn screening service. METHOD: This prospective study analyzed children with congenital toxoplasmosis identified by newborn screening (IgM anti-T.gondii) in Belo Horizonte during 2003/2004. The presence of IgM and/or IgA in the first 6 months or IgG at 12 months-of age in serology was used as case definition. Hearing tests were carried out at the time of diagnosis and 12 months later, including behavioral audiometry, evoked otoacoustic emission and brainstem evoked responses audiometry. RESULTS: Among 30.808 screened children (97% of live births), 20 had congenital toxoplasmosis, 15 (75%) were asymptomatic at birth. Nineteen children were evaluated by hearing tests. Four had sensorineural impairment (21.1%). One child had other risk factors for hearing impairment; the other three had no other risk factors but toxoplasmosis. Two properly children treated still had hearing loss, in disagreement with current literature. CONCLUSION: Results suggest that congenital toxoplasmosis, common in Brazil, is a risk factor for hearing impairment and its impact on hearing loss deserves further studies.

[Depression in schizophrenia: prevalence and relationship to quality of life]. / Depressão na esquizofrenia: prevalência e relação com a qualidade de vida.

This study aimed to investigate the prevalence of depression in schizophrenia and associated factors, including quality of life. A cross-sectional study was conducted with 150 outpatients. The Calgary Depression Scale for Schizophrenia measured depression, and the Quality of Life Scale-Brazil measured quality of life. Major depression was found in 56% of patients with schizophrenia. Patients with major depression had low quality of life according to both the global scale and the occupational subscale. Global quality of life was important for separating the decision-tree statistical analyses. In patients with low quality of life, three factors were associated with depression: presence of schizophrenic symptoms, number of medications, and lack of household activities. In patients with better quality of life scores, only duration of the illness was significant. The study shows a high prevalence of depression in schizophrenia, besides highlighting its repercussions on quality of life. When evaluating quality of life, the presence of depression should be taken into consideration.

[Quality of life and occupational domain in schizophrenia: a gender comparison]. / Qualidade de vida e dimensão ocupacional na esquizofrenia: uma comparação por sexo.

Schizophrenia has been associated with low quality of life in patients, and the impact can vary by gender. Knowing gender differences may help implement specific interventions. This study focuses on quality of life in male and female outpatients with schizophrenia, particularly examining the occupational domain. A cross-sectional study using the Quality of Life Scale (QLS-BR) was carried out. Comparisons of scores by gender used uni- and multivariate analyses by means of a classification tree through the CHAID algorithm and ordinal logistic regression. Women showed higher quality of life scores (p < 0.05). In the occupational domain, marital status was a relevant variable; single marital status (for men or women) was associated with lower quality of life as compared to married status, with OR = 10.0 (CI: 2.9-33.3) for men and OR = 4.5 (CI: 1.2-16.6) for women, respectively. Duration of illness (> 5 years) was another significant factor for lower scores. Women had better quality of life scores than men, suggesting that they have more occupational activities due to their greater participation in domestic and social activities.

[Silica exposure index in gold mining]. / Indice de exposição à sílica na atividade de mineração de ouro.

OBJECTIVE: To develop a cumulative silica exposure index, including time period, duration and intensity of exposure, and to test this index as for occurrence and severity of silicosis. METHODS: A cross-sectional study was carried out comprising 140 former gold miners from two localities in Southeastern Brazil between November 1997 and December 1999. Complete data on occupational and medical histories, chest x-rays and spirometry were analyzed. Borderline cases on the x-rays were also submitted to high-resolution chest computed tomography. The exposure index was the sum of scores obtained by logarithmic transformation of respirable silica concentration related to job tasks, mines and work time. Parametric tests were used for comparing averages between the groups of interest. RESULTS: The silica exposure index was able to discriminate the main outcome (silicosis) as well as other outcomes (tuberculosis and lung emphysema) in the whole group at p-values of 0.008, 0.016 and <0.001 respectively. In regard to the four main categories of silicosis, the Tukey test showed differences in the averages of the exposure index in the categories 0 and 3 and 1 and 3. However, in the borderline cases subgroup, the exposure index was not satisfactory for cases submitted to x-rays and tomography and it could not differentiate other outcomes. CONCLUSIONS: The silica exposure index represents an advance in exposure evaluation of former miners. However, other information, such as clinical and lung functional data are needed for better understanding disease progress in silica exposed cases, especially among borderline cases.

Factors associated with low quality of life in schizophrenia.

Interest in quality of life in mental health care has been stimulated by the deinstitutionalization of psychiatric patients as well as a parallel interest in understanding the scope of their daily lives. This study aims to investigate the socio-demographic and clinical variables related to low quality of life, using a cross-sectional design to evaluate quality of life by means of the QLS-BR scale. We interviewed a sample of 123 outpatients from a reference mental health center in Divinópolis, Minas Gerais State, Brazil, clinically diagnosed with schizophrenia. Univariate and multivariate logistic regression analyses were carried out. The results showed that low quality of life is associated with one or more of the following: male gender, single marital status, low income plus low schooling, use of three or more prescribed psychoactive drugs, psychomotor agitation during the interview, and current follow-up care. The study identifies plausible indicators for the attention and care needed to improve psychiatric patient treatment.

Sample size considerations in active-control non-inferiority trials with binary data based on the odds ratio.

This paper presents an approximate closed form sample size formula for determining non-inferiority in active-control trials with binary data. We use the odds-ratio as the measure of the relative treatment effect, derive the sample size formula based on the score test and compare it with a second, well-known formula based on the Wald test. Both closed form formulae are compared with simulations based on the likelihood ratio test. Within the range of parameter values investigated, the score test closed form formula is reasonably accurate when non-inferiority margins are based on odds-ratios of about 0.5 or above and when the magnitude of the odds ratio under the alternative hypothesis lies between about 1 and 2.5. The accuracy generally decreases as the odds ratio under the alternative hypothesis moves upwards from 1. As the non-inferiority margin odds ratio decreases from 0.5, the score test closed form formula increasingly overestimates the sample size irrespective of the magnitude of the odds ratio under the alternative hypothesis. The Wald test closed form formula is also reasonably accurate in the cases where the score test closed form formula works well. Outside these scenarios, the Wald test closed form formula can either underestimate or overestimate the sample size, depending on the magnitude of the non-inferiority margin odds ratio and the odds ratio under the alternative hypothesis. Although neither approximation is accurate for all cases, both approaches lead to satisfactory sample size calculation for non-inferiority trials with binary data where the odds ratio is the parameter of interest.

Changes in mastectomy rates at a Brazilian public hospital over 20 years (1989 to 2008).

CONTEXT AND OBJECTIVE: Recently, breast-conserving surgery (BCS) has been replacing mastectomy for breast cancer treatment. The aim of this study was to evaluate the changes in mastectomy and BCS rates and the factors relating to these shifts. DESIGN AND SETTING: A retrospective study in a Brazilian public hospital. METHODS: Pathological records from female patients who underwent surgery for breast cancer at Hospital das Clínicas, Universidade Federal de Minas Gerais (HC-UFMG), between 1989 and 2008 were reviewed. The mastectomy and BCS rates were calculated. The chi-square test was used to assess factors associated with type of surgical treatment and to compare trends in treatment type over the years. Logistic regression was used for multivariate analysis. RESULTS: From 1989 to 2008, 2050 breast cancer surgical specimens were received in our service, corresponding to 1973 patients; 1324 (64.6%) of them were from mastectomy and 726 (35.4%) from BCS. A shift from mastectomy towards BCS was observed (P < 0.001). In multivariate analysis, earlier year of surgery (P < 0.001), larger tumor size (P < 0.001), having at least one positive axillary lymph node (P < 0.001) and patients' age greater than 68 years (P = 0.007) were predictors of mastectomy. CONCLUSIONS: There was a shift from mastectomy towards BCS in our institution over the years. This may reflect consolidation of BCS (plus radiotherapy) as an equivalent treatment to mastectomy in terms of survival and a shift to earlier diagnosis for the disease.

Estudo comparativo de biodisponibilidade relativa entre duas formulações contendo Clozapina 100 mg em pacientes portadores de esquizofrenia / Comparative study of relative bioavailability between two formulations containing Clozapine 100 mg in patients with schizophrenia

Este estudo teve por objetivo avaliar a bioequivalência entre dois produtos contendo Clozapina 100 mg (produto teste: LifalClozapina® da Lifal ? Laboratório Industrial Farmacêutico de Alagoas S/A. O produto referência: Leponex® do Laboratório Novartis Biociências S/A.) em 40 voluntários. O estudo foi aberto, randomizado, do tipo cross-over, em estado de equilíbrio, com dois períodos (duas sequências), nos quais os voluntários receberam, em cada período, a formulação teste ou a formulação referência. A biodisponibilidade relativa das formulações seguidas à administração oral foi avaliada com base em comparações estatísticas de parâmetros farmacocinéticos relevantes obtidos de dados de amostra sanguínea dos voluntários, sendo as amostras coletadas em período de 24h. A concentração de Clozapina foi medida a partir de método analítico apropriado e válido. As medidas farmacocinéticas utilizadas foram: Cmin, Cmax e ASCt. As diferenças médias (± DP) entre referência e teste foram: 0,1615 ± 0,3404 (ng/mL); -0,0969 ± 0,4131 (ng/mL) e 0,9143 ± 3,9941 (ng*h/mL). Os intervalos de confiança para biequivalência média atenderam aos limites determinados pela Agência Nacional de Vigilância Sanitária (ANVISA) de 80 a 125%, sendo os dois medicamentos considerados bioequivalentes. Assim, produtos teste e referência são considerados intercambiáveis.

This study aimed to evaluate the bioequivalence between two products containing Clozapine 100 mg (testing product: LifalClozapina® from Lifal ? Industrial Pharmaceutical Laboratory of Alagoas S/A and the reference product: Leponex® from the Novartis Biociências S/A. Laboratories) in 40 volunteers. The study was open, randomized, crossover type, in a state of equilibrium, with two periods (two sequences) in which volunteers were given, in each period, the testing formulation or the reference formulation. The relative bioavailability of the formulations following oral administration was evaluated based on statistical comparisons of relevant pharmacokinetic parameters obtained from blood samples in a 24 hours period. The concentration of Clozapine was measured using an appropriate and valid analytical method. The pharmacokinetic measures used were: Cmin and Cmax, and ASCt. The mean differences (± SD) between reference and testing were: 0.1615 ± 0.3404 (ng/mL); -0.0969 ± 0.4131 (ng/mL); and 0.9143 ± 3.9941 (ng*h/ mL). The confidence intervals for medium bioequivalence met the limits determined by the National Agency of Sanitary Surveillance (ANVISA) of 80 to 125%, and both medications were considered bioequivalent. Thus, the testing and reference products are considered interchangeable

[Ordinal logistic regression in epidemiological studies]. / Regressão logística ordinal em estudos epidemiológicos.

Ordinal logistic regression models have been developed for analysis of epidemiological studies. However, the adequacy of such models for adjustment has so far received little attention. In this article, we reviewed the most important ordinal regression models and common approaches used to verify goodness-of-fit, using R or Stata programs. We performed formal and graphical analyses to compare ordinal models using data sets on health conditions from the National Health and Nutrition Examination Survey (NHANES II).

Active-control trials with binary data: a comparison of methods for testing superiority or non-inferiority using the odds ratio.

This paper considers methods for testing for superiority or non-inferiority in active-control trials with binary data, when the relative treatment effect is expressed as an odds ratio. Three asymptotic tests for the log-odds ratio based on the unconditional binary likelihood are presented, namely the likelihood ratio, Wald and score tests. All three tests can be implemented straightforwardly in standard statistical software packages, as can the corresponding confidence intervals. Simulations indicate that the three alternatives are similar in terms of the Type I error, with values close to the nominal level. However, when the non-inferiority margin becomes large, the score test slightly exceeds the nominal level. In general, the highest power is obtained from the score test, although all three tests are similar and the observed differences in power are not of practical importance.

Ordinal logistic regression models: application in quality of life studies.

Quality of life has been increasingly emphasized in public health research in recent years. Typically, the results of quality of life are measured by means of ordinal scales. In these situations, specific statistical methods are necessary because procedures such as either dichotomization or misinformation on the distribution of the outcome variable may complicate the inferential process. Ordinal logistic regression models are appropriate in many of these situations. This article presents a review of the proportional odds model, partial proportional odds model, continuation ratio model, and stereotype model. The fit, statistical inference, and comparisons between models are illustrated with data from a study on quality of life in 273 patients with schizophrenia. All tested models showed good fit, but the proportional odds or partial proportional odds models proved to be the best choice due to the nature of the data and ease of interpretation of the results. Ordinal logistic models perform differently depending on categorization of outcome, adequacy in relation to assumptions, goodness-of-fit, and parsimony.

Comparison of pharmacopeial statistical methods applied in microbiological assay for antibiotics potency determination using parallel lines and three-dose level

Pharmaceutical equivalence studies, useful for checking the interchangeability of generic medicines and their respective innovator medicines, have been carried out in Brazil since 1999, as a consequence of the establishment of the generic medicine policy. For medicines containing antibiotics, microbiological assays are often the most appropriate method. However, the statistical methods applied in these assays are not widely known due to the difficult access to official codes and/or little knowledge of the statistical tools of analysis. Thus, the aim of this work was to compare the statistical methods for determining the potency of antibiotics through the cylinder-plate method using parallel lines and a three-dose level model, as described in the Brazilian Pharmacopeia (4th edition, 1988), British Pharmacopoeia 2011, European Pharmacopoeia (7th edition), The International Pharmacopoeia (4th edition), and United States Pharmacopeia (34th edition). The assay is illustrated with the antibiotic ofloxacin, and details on orthogonal coefficients, normality test, homogeneity of variance test, and detection of outliers are discussed. The calculations obtained by statistical analyses from different pharmacopeias lead to the same final interpretation. In practice, with the availability of alternative pharmacopeial methods, the analyst can choose the most appropriate statistical calculation to be used.

Os estudos de equivalência farmacêutica, úteis na verificação da intercambialidade entre os medicamentos genéricos e respectivos medicamentos de referência, têm sido realizados no Brasil desde 1999, como consequência do estabelecimento da política de medicamentos genéricos. Para medicamentos contendo antibióticos, os ensaios microbiológicos são, muitas vezes, o método mais adequado. Entretanto, os métodos estatísticos aplicados nesses ensaios não são amplamente conhecidos devido à dificuldade de acesso aos compêndios oficiais e/ou pouca compreensão das ferramentas estatísticas de análises. Portanto, o objetivo desse trabalho foi comparar os métodos estatísticos para determinação de potência de antibióticos pelo delineamento por retas paralelas e três níveis de doses, descritos nas farmacopeias Brasileira 4. ed. (1988), Britânica 2011, Europeia 7. ed., Internacional 4. ed. e na Farmacopeia dos Estados Unidos 34. ed. (2011). O ensaio é exemplificado com o antibiótico ofloxacino e detalhes sobre coeficientes ortogonais, teste de normalidade, teste de homogeneidade de variância e detecção de outliers são discutidos. Os cálculos obtidos pelas análises estatísticas segundo as diferentes farmacopeias resultaram na mesma interpretação final. Na prática, métodos farmacopéicos alternativos permitem ao analista a escolha do cálculo estatístico mais apropriado a ser utilizado.

Changes in mastectomy rates at a Brazilian public hospital over 20 years (1989 to 2008) / Mudanças nas taxas de mastectomia em um hospital público brasileiro ao longo de 20 anos (1989 a 2008)

CONTEXT AND OBJECTIVE: Recently, breast-conserving surgery (BCS) has been replacing mastectomy for breast cancer treatment. The aim of this study was to evaluate the changes in mastectomy and BCS rates and the factors relating to these shifts. DESIGN AND SETTING: A retrospective study in a Brazilian public hospital. METHODS: Pathological records from female patients who underwent surgery for breast cancer at Hospital das Clínicas, Universidade Federal de Minas Gerais (HC-UFMG), between 1989 and 2008 were reviewed. The mastectomy and BCS rates were calculated. The chi-square test was used to assess factors associated with type of surgical treatment and to compare trends in treatment type over the years. Logistic regression was used for multivariate analysis. RESULTS: From 1989 to 2008, 2050 breast cancer surgical specimens were received in our service, corresponding to 1973 patients; 1324 (64.6%) of them were from mastectomy and 726 (35.4%) from BCS. A shift from mastectomy towards BCS was observed (P < 0.001). In multivariate analysis, earlier year of surgery (P < 0.001), larger tumor size (P < 0.001), having at least one positive axillary lymph node (P < 0.001) and patients' age greater than 68 years (P = 0.007) were predictors of mastectomy. CONCLUSIONS: There was a shift from mastectomy towards BCS in our institution over the years. This may reflect consolidation of BCS (plus radiotherapy) as an equivalent treatment to mastectomy in terms of survival and a shift to earlier diagnosis for the disease.

CONTEXTO E OBJETIVO: Recentemente, a cirurgia conservadora tem substituído a mastectomia para tratamento cirúrgico do câncer de mama. O objetivo deste estudo é avaliar as mudanças nas taxas de mastectomia e cirurgia conservadora e os fatores relacionados a essas mudanças. TIPO DE ESTUDO E LOCAL: Estudo retrospectivo em hospital público brasileiro. MÉTODOS: Dados patológicos das pacientes submetidas a cirurgia para câncer de mama no Hospital das Clínicas, Universidade Federal de Minas Gerais (HC-UFMG), de 1989 a 2008, foram revistos. As taxas de mastectomia e cirurgia conservadora foram calculadas. O teste qui-quadrado foi usado para avaliar fatores relacionados ao tipo de tratamento cirúrgico empregado e comparar tendências de tipo de tratamento ao longo dos anos. Regressão logística foi usada para análise multivariada. RESULTADOS: De 1989 a 2008, 2.050 espécimes cirúrgicos de câncer de mama foram recebidos em nosso serviço, correspondentes a 1.973 pacientes; 1.324 (64,6%) correspondentes a mastectomia e 726 (35,4%) correspondentes a cirurgia conservadora. A cirurgia conservadora se tornou mais frequente ao longo dos anos (P < 0,001). Em análise multivariada, ano mais precoce da cirurgia (P < 0,001), maior tamanho tumoral (P < 0,001), ter ao menos um linfonodo axilar positivo (P < 0,001) e idade maior de 68 anos (P = 0,007) foram preditores de mastectomia. CONCLUSÕES: As cirurgias conservadoras se tornaram mais frequentes em relação às mastectomias ao longo dos anos. Isso pode refletir a consolidação da cirurgia conservadora (associada a radioterapia) como equivalente à mastectomia em termos de sobrevida, bem como diagnóstico mais precoce da doença.

Continued exposure to silica after diagnosis of silicosis in Brazilian gold miners.

BACKGROUND: There is a paucity of studies analyzing the effect of continued silica exposure after the onset of silicosis with regard to disease progression. The present study investigates differences in clinical and radiological presentation of silicosis among former workers with a diagnosis of silicosis, and compares workers who continued to be exposed to silica with those who stopped silica exposure after having received their diagnosis. METHODS: A sample of 83 former gold miners with a median of 21 years from the first diagnoses of silicosis, had their clinical and occupational histories taken and underwent both chest radiography (International Labor Organization standards) and spirometry. Their silica exposure was assessed and an exposure index was created. The main outcome was the radiological severity of silicosis and tuberculosis (TB). The statistical analysis was done by multiple logistic regression. RESULTS: Among the 83 miners, 44 had continued exposed to silica after being diagnosed with silicosis. Continuation of silica exposure was associated with advanced radiological images of silicosis (X-ray classification in category 3, OR = 6.42, 95% CI = 1.20-34.27), presence of coalescence and/or large opacities (OR = 3.85, CI = 1.07-13.93), and TB (OR = 4.61, 95% CI = 1.14-18.71). CONCLUSIONS: Differential survival is unlikely to explain observed differences in silicosis progression. Results reinforce the recommendation that silica exposure should be halted at an early stage whenever X-ray is suggestive of the disease.

Dried blood spots as a practical and inexpensive source for human immunodeficiency virus and hepatitis C virus surveillance.

Passive surveillance of infectious diseases with a high percentage of asymptomatic cases or long incubation periods, such as acquired immunodeficiency syndrome (AIDS), does not reflect the current transmission dynamics. Thus, a multi-strategic surveillance, such as the human immunodeficiency virus (HIV) sentinel surveillance proposed by the World Health Organization (WHO), is necessary. The Brazilian HIV sentinel surveillance was started in May 1992 with this purpose. The objectives of this study were to evaluate the feasibility and costs of HIV and hepatitis C virus (HCV) surveillance using dried blood spots (DBS) collected for neonatal screening of metabolic diseases in the state of Minas Gerais, Brazil. This was accomplished through the comparison of HIV and HCV seroprevalence with previous Brazilian studies. From December 2001 to June 2002, 24,905 newborns were tested for HIV and 4211 for HCV. HIV seroprevalence was 0.25% and the 95% confidence interval (CI) was 0.18, 0.31%; and HCV seroprevalence was 0.71% and the 95% CI was 0.46, 0.97%. These numbers are similar to previous Brazilian studies. Cost in this study was approximately USD 3.10 per sample, which was roughly one third of the cost of the same exam at the Brazilian HIV sentinel surveillance. We conclude that it is possible and more cost-effective to use DBS for infectious diseases surveillance, albeit it is still necessary to compare these results with the usual sentinel methodology in a concomitant trial.

Regressão logística ordinal em estudos epidemiológicos / Regresión logística ordinal en estudios epidemiológicos / Ordinal logistic regression in epidemiological studies

Os modelos de regressão logística ordinal vêm sendo aplicados com sucesso na análise de estudos epidemiológicos. Entretanto, a verificação da adequação de cada modelo tem recebido atenção limitada. O artigo apresenta uma breve análise dos principais modelos de regressão logística ordinal e as estratégias para ajuste s, as técnicas de verificação de qualidade do ajuste, bem como os comandos para execução nos softwares R e Stata. A metodologia é ilustrada com aplicação dos dados do Second National Health and Nutrition Examination Survey (NHANES II), o conhecido levantamento de saúde e nutrição.

Ordinal logistic regression models have been developed for analysis of epidemiological studies. However, the adequacy of such models for adjustment has so far received little attention. In this article, we reviewed the most important ordinal regression models and common approaches used to verify goodness-of-fit, using R or Stata programs. We performed formal and graphical analyses to compare ordinal models using data sets on health conditions from the National Health and Nutrition Examination Survey (NHANES II).

Los modelos de regresión logística ordinal vienen aplicándose con éxito en el análisis de estudios epidemiológicos. Sin embargo, la verificación de la adecuación de cada modelo ha recibido atención limitada. El artículo presenta un breve análisis de los principales modelos de regresión logística ordinal y las estrategias para ajustes, las técnicas de verificación de calidad de ajuste, así como los comandos para ejecución en los softwares R y Stata. La metodología es ilustrada con la aplicación de los datos del Second Nacional Health and Nutrition Examination Survey (NHANES II), el conocido análisis de salud y nutrición.

Ordinal logistic regression models: application in quality of life studies: [review] / Modelos de regressão logística ordinal: aplicação em estudo sobre qualidade de vida: [revisão]

Quality of life has been increasingly emphasized in public health research in recent years. Typically, the results of quality of life are measured by means of ordinal scales. In these situations, specific statistical methods are necessary because procedures such as either dichotomization or misinformation on the distribution of the outcome variable may complicate the inferential process. Ordinal logistic regression models are appropriate in many of these situations. This article presents a review of the proportional odds model, partial proportional odds model, continuation ratio model, and stereotype model. The fit, statistical inference, and comparisons between models are illustrated with data from a study on quality of life in 273 patients with schizophrenia. All tested models showed good fit, but the proportional odds or partial proportional odds models proved to be the best choice due to the nature of the data and ease of interpretation of the results. Ordinal logistic models perform differently depending on categorization of outcome, adequacy in relation to assumptions, goodness-of-fit, and parsimony.

O tema qualidade de vida tem ganhado ênfase nos últimos anos. Tipicamente os resultados da qualidade de vida são mensurados por meio de escalas ordinais. Procedimentos como dicotomizar a variável resposta e desconsiderar a ordenação geram perda de informação e podem ocasionar inferências incorretas. Para análise de dados ordinais, métodos estatísticos específicos são necessários, como modelos de regressão logística ordinal. A proposta deste trabalho é apresentar uma revisão dos modelos de chances proporcionais, de razão contínua, estereótipo e de chances proporcionais parciais. O ajuste, inferência estatística e comparação dos modelos são ilustrados com dados de um estudo sobre qualidade de vida realizado com 273 pacientes com esquizofrenia. Todos os modelos testados mostraram bom ajuste, mas o de chances proporcionais e o de chances proporcionais parciais foram os mais adequados pelo caráter dos dados utilizados e facilidade da interpretação dos resultados. Nem sempre todos os modelos são apropriados, daí a importância de uma escolha cuidadosa, baseada em vários fatores como caráter da variável ordinal, validade dos pressupostos, qualidade do ajuste e parcimônia.

A silicose e o perfil dos lapidários de pedras semipreciosas em Joaquim Felício, Minas Gerais, Brasil / Silicosis among semiprecious gem cutters in Joaquim Felício, Minas Gerais State, Brazil

Para conhecer a prevalência de silicose, descrever os perfis clínico, epidemiológico e ocupacional, e estudar as condições de trabalho das oficinas de lapidação, realizou-se estudo transversal de setenta lapidários de pedras semipreciosas de Joaquim Felício, Minas Gerais, Brasil, de abril a dezembro de 2002. Utilizaram-se história ocupacional com questionário respiratório, radiografia de tórax e espirometria. A prevalência de silicose foi de 7,1 por cento. Todos eram do sexo masculino, com média de idade de 21,5 anos e tempo médio de exposição à sílica de 7,1 anos. Todos pertenciam ao setor da economia informal e trabalhavam em oficinas pequenas e rudimentares, sendo o maquinário improvisado e havendo maciça exposição à sílica. Segundo a Classificação Radiológica da Organização Internacional do Trabalho, dos cinco casos de silicose, quatro foram classificados na categoria 1, e um na 3. A silicose em lapidários constitui um sério problema de saúde pública que requer esforços para minimização do risco de adoecimento, por meio da ação de equipes multidisciplinares provenientes de instituições governamentais e não-governamentais, com inserção ativa dos trabalhadores.

A cross-sectional study was performed to determine the prevalence of silicosis among semiprecious gem cutters (n = 70) and describe their clinical, epidemiological, and occupational profiles in Joaquim Felício, Minas Gerais State, Brazil, from April to December 2002. Occupational history was used with a respiratory questionnaire, chest x-ray, and spirometry. Silicosis prevalence was 7.1 percent. All affected individuals were men, with a mean age of 21.5 and mean exposure to silica of 7.1 years. All belonged to the informal economy and had been working at small and rudimentary workshops, using improvised lathes, with intense exposure to silica dust. According to the ILO Radiological Classification, four of the five cases of silicosis were classified as grade 1 and one as grade 3. Silicosis among gem cutters constitutes a serious public health problem that requires efforts to minimize risk through work by multidisciplinary teams from government agencies and nongovernmental organizations, with active participation by the workers themselves.