Submitted by (ana.araujo@ufrpe.br) on 2016-06-28T13:38:54Z No. of bitstreams: 1 Damocles Aurelio Nascimento da Silva.pdf: 694209 bytes, checksum: 1f6f75597b9348c94d982a8d8a612c8e (MD5) / Made available in DSpace on 2016-06-28T13:38:54Z (GMT). No. of bitstreams: 1 Damocles Aurelio Nascimento da Silva.pdf: 694209 bytes, checksum: 1f6f75597b9348c94d982a8d8a612c8e (MD5) Previous issue date: 2006-02-24 / Aiming at to contribute, as alternative to minimize the resources of impacts,mainly, for the search of combustible material to take care of the energy demand of the Brazilian half-barren region, we use the techniques of analysis of survival for understanding of a forest of eucalyptus to the long one of the time, and with this to ration the use wooden as combustible for ceramics, bakeries and existing calcinatory of plaster in region. The data given proceeding from a transversal study of 1500 cells of eucalyptus, divided in 4 stratus, taking as base the period of 03/2002 to 09/2004. The graph of probability was used initially for, being based on the test of Anderson-Darling, takes the decision of which function of probability would use in such a way in the classic study as in the Bayesian boarding. A time taken to the decision of choice of the probability distribution, we use the method of Kaplan-Meier and the Actuarial method (life table) to determine the estimates of the parameters and the test distribution free log-rank to test if the curves of the function of probability differed between categories from one same one variable. We used this test to the level of significance of 5%. For these analyses, it was used statistical software Minitab 13 version and statistical package SAS.In the Bayesian boarding was used method Carlo the Mount Chain of Markov (MCMC) for estimate of parameters, using as priori the distribution gamma,found in literature as the distribution that more good was adjusted for biological data and as function of density, used it of the Weibull distribution, chosen as of the better adjustment to the data according to test of Anderson-darling. For thisanalysis software Winbugs 1.4 was used. The results how much to the analysis of the parameters they had indicated that the joined estimates had been closed, same using distinct methods of estimation. As much was concluded that the best distribution to analyze the population in question is the Weibull, according to test of Anderson-Darling and as method for estimation of the parameters of the distribution, the classic method,how much the Bayesian method, reveals good estimators, verified for the amplitude of the intervals reliable 95%. In face of the results, we conclude that if it must have one better control of the eucalyptus, in first the six months of the plantation. / Visando contribuir, como alternativa para minimizar os impactos antrópicos de caracter negativo causado, principalmente, pela busca de material combustível para atender a demanda energética da região semi-árida brasileira, utilizamos as técnicas de análise de sobrevivência para compreensão do comportamento de uma floresta de eucaliptos ao longo do tempo, e com isto racionar o uso de madeira como combustível por cerâmicas, padarias, casas de farinha e calcinadoras de gesso existentes na região. Usaremos dados provenientes de um estudo transversal de 1500 células de eucaliptos, dividido em 4 estratos, tomando como base o período de 03/2002 a 09/2004.Utilizou-se inicialmente o gráfico de probabilidade para, baseado no teste de Anderson-Darling, tomarmos a decisão de qual função de probabilidade utilizaríamos tanto no estudo clássico como na abordagem bayesiana. Uma vez tomada a decisão de escolha da distribuição de probabilidade, utilizamos o método de Kaplan-Meier e o método Atuarial (tábua de vida) para estimativa dos parâmetros e o teste não paramétrico log-rank para testar se as curvas da função de probabilidade diferiam entre categorias de uma mesma variável. Utilizamos esse teste ao nível de significância de 0,05. Para essas análises, foi utilizado o software estatístico Minitab versão 13 e o pacote estatístico SAS.Na abordagem bayesiana utilizou-se a o método de Monte Carlo Cadeia de Markov (MCMC) para estimativa dos parâmetros, utilizando como priori a distribuição gamma, encontrada na literatura como a distribuição que melhor adequa-se para dados biológicos e como função de densidade, utilizou-se a da distribuição Weibull, escolhida como a de melhor ajuste as dados segundo o teste de Anderson-Darling. Para essa análise foi utilizado o Winbugs 1.4.Os resultados quanto a análise dos parâmetros indicaram que as estimativas encontradas foram próxima, mesmo utilizando métodos de estimação distintos. Conclui-se que a melhor distribuição para analisar a população em questão é a Weibull, segundo o teste de Anderson-Darling e como método para estimação dos parâmetros da distribuição, tanto o método clássico, quanto o método bayesiano, mostram-se bons estimadores, verificado pela amplitude dos intervalos de confiança a 95%. Em face dos resultados, concluímos que deve-seter um melhor controle dos eucaliptos, nos primeiros 6 meses de plantio.

Introdução: O excesso de peso em adultos jovens está associado ao desenvolvimento de doenças crônicas não transmissíveis (DCNT) e à diminuição da qualidade de vida e ao aumento da mortalidade precoce. A transição da adolescência para a fase adulta é o período de maior risco para a incidência da obesidade. Objetivo: Estimar o efeito o índice de massa corpora (IMC) aos 20 anos sobre a incidência de DCNT em adultos brasileiros com idade entre 30 a 49 anos. Métodos: Foram selecionados 12.079 indivíduos de 30 a 49 anos da Pesquisa Nacional de Saúde (PNS), realizada no ano de 2013. O modelo adotado para determinação das DCNT foi aquele proposto pela Organização Mundial de Saúde. A incidência das DCNT (hipertensão, doenças cardiovasculares, diabetes e câncer, entre outras), informada pela data do diagnóstico, foi modelada como função do IMC aos 20 anos. Os indivíduos sem a doença até o presente foram considerados como censura. As estimativas de sobrevida foram calculadas com o método de Kaplan-Meier (KM) para cada uma das doenças, estratificada por sexo e ajustada por escolaridade. A análise dos fatores de risco para as doenças foi feita utilizando-se o modelo de riscos proporcionais de Cox. Resultados: Nas curvas de sobrevida KM, indivíduos com IMC >=25kg/m² apresentaram incidência mais elevada e precoce de DCNT, principalmente hipertensão, diabetes e depressão. A idade mediana para incidência do diabetes em obesos foi de 47 anos para homens e 48 anos para mulheres. A incidência da hipertensão arterial foi 4,2 por mil com sobrevida mediana de 48 e 44 anos em mulheres com excesso de peso e obesidade, respectivamente. Dentre os fatores de risco associados as DCNT, o tabagismo em idade precoce foi associado à incidência de depressão. Conclusão: O excesso de peso em adultos jovens aumenta a incidência precoce de DCNT, com efeitos negativos na qualidade de vida, lazer e produtividade, além de aumentar a demanda por serviços de saúde. Torna-se necessário que a intervenção para redução dessas doenças seja direcionada para o período da infância e adolescência com ações que promovam a redução da exposição desses indivíduos à alimentação de má qualidade e incentivo a prática de atividade, não uso do tabaco e consumo moderado de álcool. / Introduction: Overweight in young adults is associated with the development of chronic noncommunicable diseases (NCDs) and decreased quality of life and increased early mortality. The transition from adolescence to adulthood is the period of greatest risk for the incidence of obesity. Objective: To estimate the effect of the corpora mass index (BMI) at age 20 on the incidence of NCDs in Brazilian adults aged 30-49 years. Methods: We selected 12 079 individuals 30-49 years of the National Health Research (PNS) held in 2013. The model adopted for determining the NCD was that proposed by the World Health Organization The incidence of NCDs (hypertension, diseases. cardiovascular, diabetes and cancer, among others), informed by the date of diagnosis, and modeled as a function of BMI at age 20. Individuals without the disease to date have been considered as censorship. Survival estimates calculated with the Kaplan-Meier (KM) for each of the diseases, stratified by gender and adjusted for schooling. The analysis of risk factors for the disease made using the model of Cox proportional hazards. Results: In the survival curves KM, individuals with BMI> = 25 kg / m² presented higher and early incidence of NCDs, particularly hypertension, diabetes and depression. The median age for incidence of diabetes in obese was 47 years for men and 48 years for women. The incidence of hypertension was 4.2 per thousand with a median survival of 48 and 44 years in women with excess weight and obesity respectively. Among the risk factors associated with the NCD, smoking at an early age was associated with the incidence of depression. Conclusion: Being overweight in young adults increases the early incidence of NCDs, with negative effects on quality of life, leisure and productivity, and increase the demand for health services. It is necessary that the intervention to reduce these diseases directed to the period of childhood and adolescence with actions that promote a reduction in exposure of these individuals to the poor quality of food and encouraging the practice of activity, no tobacco use and moderate consumption alcohol.

O modelo semiparamétrico de Cox é frequentemente utilizado na modelagem de dados de sobrevivência, pois é um modelo muito flexível e permite avaliar o efeito das covariáveis sobre a taxa de falha. Uma das principais vantagens é a fácil interpretação, de modo que a razão de riscos de dois indivíduos não varia ao longo do tempo. No entanto, em algumas situações a proporcionalidade dos riscos para uma dada covariável pode não ser válida e, este caso, uma abordagem que não dependa de tal suposição é necessária. Nesta tese, propomos um modelo tipo Cox em que o efeito da covariável e a função de risco basal são representadas via bases de Fourier e ondaletas de Haar clássicas e deformadas. Propomos também um procedimento de predição da função de sobrevivência para um paciente específico. Estudos de simulações e aplicações a dados reais sugerem que nosso método pode ser uma ferramenta valiosa em situações práticas em que o efeito da covariável é dependente do tempo. Por meio destes estudos, fazemos comparações entre as duas abordagens propostas, e comparações com outra já conhecida na literatura, onde verificamos resultados satisfatórios. / The semiparametric Cox model is often considered when modeling survival data. It is very flexible, allowing for the evaluation of covariates effects. One of its main advantages is the easy of interpretation, as long as the rate of the hazards for two individuals does not vary over time. However, this proportionality of the hazards may not be true in some practical situations and, in this case, an approach not relying on such assumption is needed. In this thesis we propose a Cox-type model that allows for time-varying covariate effects, for which the baseline hazard is based on Fourier series and wavelets on a time-frequency representation. We derive a prediction method for the survival of future patients with any specific set of covariates. Simulations and an application to a real data set suggest that our method may be a valuable tool to model data in practical situations where covariate effects vary over time. Through these studies, we make comparisons between the two approaches proposed here and comparisons with other already known in the literature, where we verify satisfactory results.

O modelo semiparamétrico de Cox é frequentemente utilizado na modelagem de dados de sobrevivência, pois é um modelo muito flexível e permite avaliar o efeito das covariáveis sobre a taxa de falha. Uma das principais vantagens é a fácil interpretação, de modo que a razão de riscos de dois indivíduos não varia ao longo do tempo. No entanto, em algumas situações a proporcionalidade dos riscos para uma dada covariável pode não ser válida e, este caso, uma abordagem que não dependa de tal suposição é necessária. Nesta tese, propomos um modelo tipo Cox em que o efeito da covariável e a função de risco basal são representadas via bases de Fourier e ondaletas de Haar clássicas e deformadas. Propomos também um procedimento de predição da função de sobrevivência para um paciente específico. Estudos de simulações e aplicações a dados reais sugerem que nosso método pode ser uma ferramenta valiosa em situações práticas em que o efeito da covariável é dependente do tempo. Por meio destes estudos, fazemos comparações entre as duas abordagens propostas, e comparações com outra já conhecida na literatura, onde verificamos resultados satisfatórios. / The semiparametric Cox model is often considered when modeling survival data. It is very flexible, allowing for the evaluation of covariates effects. One of its main advantages is the easy of interpretation, as long as the rate of the hazards for two individuals does not vary over time. However, this proportionality of the hazards may not be true in some practical situations and, in this case, an approach not relying on such assumption is needed. In this thesis we propose a Cox-type model that allows for time-varying covariate effects, for which the baseline hazard is based on Fourier series and wavelets on a time-frequency representation. We derive a prediction method for the survival of future patients with any specific set of covariates. Simulations and an application to a real data set suggest that our method may be a valuable tool to model data in practical situations where covariate effects vary over time. Through these studies, we make comparisons between the two approaches proposed here and comparisons with other already known in the literature, where we verify satisfactory results.

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In the dissertation, we study the statistical evaluation of treatment comparisons by evaluating the relative comparison of survival experiences between two treatment groups. We construct confidence interval and simultaneous confidence bands for the ratio and odds ratio of two survival functions through both parametric and nonparametric approaches.We first construct empirical likelihood confidence interval and simultaneous confidence bands for the odds ratio of two survival functions to address small sample efficacy and sufficiency. The empirical log-likelihood ratio is developed, and the corresponding asymptotic distribution is derived. Simulation studies show that the proposed empirical likelihood band has outperformed the normal approximation band in small sample size cases in the sense that it yields closer coverage probabilities to chosen nominal levels.Furthermore, in order to incorporate prognostic factors for the adjustment of survival functions in the comparison, we construct simultaneous confidence bands for the ratio and odds ratio of survival functions based on both the Cox model and the additive risk model. We develop simultaneous confidence bands by approximating the limiting distribution of cumulative hazard functions by zero-mean Gaussian processes whose distributions can be generated through Monte Carlo simulations. Simulation studies are conducted to evaluate the performance for proposed models. Real applications on published clinical trial data sets are also studied for further illustration purposes.In the end, the population attributable fraction function is studied to measure the impact of risk factors on disease incidence in the population. We develop semiparametric estimation of attributable fraction functions for cohort studies with potentially censored event time under the additive risk model.

Background Studies based on a cohort design requires access to both subject-specific and period-specific information. In order to conduct an occupational cohort study, access to exposure information and the possibility and permission to link information on outcomes from other registers are generally necessary. The analysis phase is also aggravated by its added complexity because of the longitudinal dimension of the cohort’s data.This thesis aims at increasing the knowledge on hazards from work on fatalities and cancer within the domain of cohort studies on miners and metal refiners and to study the complexity of the analysis by discussing and suggesting analytical strategies. Methods The study population for this thesis consisted of a cohort of 2264 blue-collar aluminium smelter workers (paper I) and a cohort of 13000 blue-collar iron-ore miners (papers II-IV), both followed for over 50 years. The outcomes were collected from the Swedish Cause of Death Register and the Swedish Cancer Register. The primary methods of analysis were either Standardized Morbidity Ratios (SMR) or internal comparisons based on Cox or Poisson regression modeling. In paper IV, a g-estimation based on an accelerated failure-time model was performed to estimate the survival ratio. Results The results from paper I suggested that working as a blue-collar worker metal refiner was associated with increased rates of incidental lung cancer. Elevated rates among short term workers were observed for several outcomes. Paper I also showed that the choice of reference population when calculating SMR could influence the conclusions of the results. In paper II, several outcomes were elevated among the miners compared to the reference population from northern Sweden. However, no outcome except lung cancer was associated with cumulative employment time. The most recurrent pattern of the results was the negative association between cumulative employment time underground and several outcomes. The results from paper III showed that cumulative employment time working outdoors was associated with increased rates of cerebrovascular disease mortality. However, employment with heavy physical workloads did not explain the previously observed decreasing rates in the selected groups of outcomes. The adjustment for the healthy worker survivor effect by g-estimation in paper IV suggested that exposure from respirable dust was associated with elevated mortality risks that could not be observed with standard analytical methods. Conclusion Our studies found several rates from the cohorts that were elevated compared to external refererence populations but also that long term employments generally were associated with decreasing rates. Furthermore, incidental lung cancer rates was found elevated for the metal refiners. Among the miners, mortality rates of cerebrovascular diseases depended on if work was performed outdoor (higher rates) or underground (lower rates). Methodologically, this thesis has discussed different analytical strategies for handling confounding in occupational cohort studies. Paper IV showed that the healthy worker survivor effect could be adjusted for by performing g-estimation.

Mirtingumo nuo įvairių ligų įvertinimas ir prognozavimas pagal atlikto tyrimo duomenis – dažnas statistinės analizės uždavinys medicinoje. Juose siekiama prognozuoti tikėtiną mirčių nuo tiriamos ligos skaičių, susirgimo tam tikra liga tikimybę ar išskirti rizikos grupes, įvertinant tyrimo metu surinktų stebimos populiacijos imties kintamųjų duomenis ir nustatant, kokia priklausomybę juos sieja. Pagrindiniai šio darbo tikslai: susipažinti su statistikos metodais, taikomais mirtingumo duomenų analizei; sudaryti statistinės analizės modelius turimiems mirtingumo duomenims; realizuoti sudarytus modelius programiškai, panaudojant SAS sistemą ir SAS makro programavimo galimybes. Panaudojus Puasono, logistinės ir Kokso regresin��s analizės metodus sudaryti mirtingumo nuo galvos smegenų insulto (GSI) prognozavimo modeliai. Sudaryti modeliai realizuoti programiškai, panaudojus SAS programavimo kalbą, SAS/IML posistemės galimybes ir SAS makro programavimo priemones. Sukurti regresinės analizės modeliai ir programines priemonės panaudotos Kauno medicinos universiteto Kardiologijos instituto 1980-2004 metais atliktų tyrimų metu surinktų Kauno miesto 25-64 m. amžiaus gyventojų mirtingumo nuo GSI duomenų analizei atlikti. / Estimation and forecasting of mortality from various diseases are very frequent data analysis tasks in medicine nowadays. In order to estimate expected number of deaths, probability to die from a disease or trends in mortality we should apply the most suitable statistical methods. Data analysis models were created using Poisson, logistic, Cox regression methods and realized in SAS macros. Created software also contains models for goodness of fit analysis, graphical visualization and prepares a report of data analysis in RTF (Rich Text Format) format. Analysis was made for mortality from stroke data among Kaunas population aged 25 to 64 during the period 1980-2004. The study contains the description of applying created data analysis models, SAS macros and received results.

In the dissertation, we study the statistical evaluation of treatment comparisons by evaluating the relative comparison of survival experiences between two treatment groups. We construct confidence interval and simultaneous confidence bands for the ratio and odds ratio of two survival functions through both parametric and nonparametric approaches.We first construct empirical likelihood confidence interval and simultaneous confidence bands for the odds ratio of two survival functions to address small sample efficacy and sufficiency. The empirical log-likelihood ratio is developed, and the corresponding asymptotic distribution is derived. Simulation studies show that the proposed empirical likelihood band has outperformed the normal approximation band in small sample size cases in the sense that it yields closer coverage probabilities to chosen nominal levels.Furthermore, in order to incorporate prognostic factors for the adjustment of survival functions in the comparison, we construct simultaneous confidence bands for the ratio and odds ratio of survival functions based on both the Cox model and the additive risk model. We develop simultaneous confidence bands by approximating the limiting distribution of cumulative hazard functions by zero-mean Gaussian processes whose distributions can be generated through Monte Carlo simulations. Simulation studies are conducted to evaluate the performance for proposed models. Real applications on published clinical trial data sets are also studied for further illustration purposes.In the end, the population attributable fraction function is studied to measure the impact of risk factors on disease incidence in the population. We develop semiparametric estimation of attributable fraction functions for cohort studies with potentially censored event time under the additive risk model.

Made available in DSpace on 2016-08-19T17:24:51Z (GMT). No. of bitstreams: 1 Tese-AnaValeriaCarvalhoPiresYokokura.pdf: 6263679 bytes, checksum: 10e62a4122185fac92398004b9092d42 (MD5) Previous issue date: 2016-02-18 / Some research shows that coping with stressful situations during pregnancy decreases the breastfeeding time, however this association has been little studied in the world. This study had two objectives: to analyze the validity of the Perceived Stress Scale in a sample of 1447 pregnant women in Sao Luis, MA and 1392 in Ribeirão Preto-SP; and analyze the effect of stress during pregnancy on the duration of breastfeeding in 1134 mother pairs / son of St. Louis. In the first article we evaluated the PSS versions with 10 and 14 items through Confirmatory Factor Analysis using the mplus 7.0, and a new version was created (PSS12) from the deletion of two items that had low factor loadings (<0.40). The models were estimated by the method of least squares (WLSMV) adjusted for mean and variance. Models with two factors showed good fit (RMSEA <0.08; CFI / TLI> 0.90) and high internal consistency (α> 0.80) in the three tested versions. In the second article we used the perceived stress scale (PSS14) and Reporting of stressful life events (EVE) to assess stress. PSS14 evaluates perceived stress during the last month. The EVE assessed stressful life events in the last twelve months. The theoretical model was designed in Acyclic Directed Graph (DAG). Survival curves were estimated using the Kaplan-Meier method. We used model of Cox proportional hazards, estimating the hazard ratio (HR) and 95%. The perceived stress during pregnancy was associated with a shorter duration of total breastfeeding (AMT) (HR=1,54; IC95%:1,23-1,93), but had no effect on exclusive breastfeeding time (AME). It was found that the PSS was adequate to assess stress in pregnant women in two cities in different regions. It suggests the use of PSS10 in the evaluation of perceived stress in pregnant women, considering their practical use, because it is a short range and its excellent fit indices. It was also found that the PEACE proved to be a tool to better identify stress than EVE. / Pesquisas mostram que o enfretamento de situações estressantes durante a gravidez diminui o tempo da amamentação, porém esta associação tem sido pouco estudada. O presente estudo teve dois objetivos: analisar a validade da Escala de Estresse Percebido numa amostra de 1447 gestantes de São Luís-MA e 1392 de Ribeirão Preto-SP; e analisar o efeito do estresse materno na duração da amamentação em 1134 pares mãe/filho de São Luís. No primeiro artigo foram avaliadas as versões PSS com 10 e 14 itens por meio da Análise Fatorial Confirmatória, utilizando o MPLUS 7.0, e foi criada uma nova versão da Escala de Estresse Percebido (PSS12) a partir da exclusão de dois itens que apresentaram cargas fatoriais baixas (<0,40). Os modelos foram estimados pelo método dos mínimos quadrados (WLSMV) ajustados pela média e variância. Os modelos com dois fatores apresentaram bom ajuste (RMSEA <0,08; CFI/TLI >0,90) e consistência interna elevada (α>0,80) nas três versões testadas. No segundo artigo utilizou-se a Escala de estresse percebido (PSS14) e Relato de eventos de vida estressantes (EVE) para avaliar estresse. A PSS14 avaliou estresse percebido durante o último mês. O EVE avaliou eventos estressantes nos últimos doze meses. O modelo teórico foi desenhado em Gráfico Acíclico Direcionado (DAG). As curvas de sobrevida foram estimadas pelo método de Kaplan-Meier. Utilizou-se modelo de riscos proporcionais de Cox, estimando-se a hazard ratio (HR) e IC95%. O estresse percebido na gestação associou-se com a menor duração do aleitamento materno total (AMT) (HR=1,54; IC95%:1,23-1,93), porém não teve efeito sobre o tempo de aleitamento materno exclusivo (AME). Constatou-se que a PSS mostrou-se adequada para avaliar estresse em gestantes, em duas cidades de diferentes regiões brasileiras. Sugere-se a utilização da PSS10 na avaliação do estresse percebido em gestantes, considerando sua utilidade prática, por ser uma escala resumida e seus excelentes índices de ajuste. Verificou-se também que a PSS se mostrou um instrumento capaz de identificar melhor o estresse do que o EVE.