Bioestatística e epidemiologia: perguntas que você sempre quis fazer, mas nunca teve coragem / Biostatistics and epidemiology: questions you always wanted to ask but never had the courage to

Dando continuidade aos artigos da série "Perguntas que você sempre quis fazer, mas nunca teve coragem", que tem como objetivo responder e sugerir referências para o melhor entendimento das principais dúvidas estatísticas levantadas por pesquisadores da área da saúde, este terceiro artigo aborda o contexto epidemiológico. Neste contexto, foram diferenciadas as principais medidas como prevalência, incidência, Odds Ratio (OR), Risco Relativo (RR), Razão de Prevalência (RP) e Hazard Ratio (HR), foi esclarecido o uso de análises por intenção de tratar e análise por protocolo, e também discutidos alguns dos termos comumente utilizados e pouco compreendidos como tipo de amostra, nível de evidência, relevância clínica e estatística, entre outros. (AU)

Continuing the series of articles "Questions you always wanted to ask but never had the courage to," which aims to answer key statistical questions raised by health researchers and suggest references for a better understanding, this third article addresses the epidemiological context. In this context, important measures such as prevalence, incidence, odds ratio (OR), relative risk (RR), prevalence ratio (PR) and hazard ratio (HR) were differentiated; the use of intention-to-treat analysis and per-protocol analysis was clarified; and some terms commonly used and poorly understood were discussed, such as type of sample, level of evidence, clinical and statistical relevance, among others. (AU)

Brazilian normative data for the Short Form 36 questionnaire, version 2 / Dados normativos brasileiros do questionario Short Form-36 versao 2

METHODS: The study Pesquisa Dimensões Sociais das Desigualdades (PDSD) (Social Dimensions of Inequalities) involves 12,423 randomly selected Brazilian men and women aged 18 years old or more from urban and rural areas of the five Brazilian regions, and the information collected included the SF-36 as a measure of health-related quality of life. This provided a unique opportunity to develop age and gender-adjusted normative data for the Brazilian population. RESULTS: Brazilian men scored substantially higher than women on all eight domains and the two summary component scales of the SF-36. Brazilians scored less than their international counterparts on almost all of SF-36 domains and both summary component scales, except on general health status (US), pain (UK) and vitality (Australia, US and Canada). CONCLUSION: The differences in the SF-36 scores between age groups, genders and countries confirm that these Brazilian norms are necessary for comparative purposes. The data will be useful for assessing the health status of the general population and of patient populations, and the effect of interventions on health-related quality of life. .

MÉTODOS: A Pesquisa Dimensões Sociais das Desigualdades (PDSD) é um inquérito que entrevistou 12.423 homens e mulheres brasileiros com idade de 18 anos e mais, selecionados aleatoriamente em áreas urbanas e rurais das cinco regiões brasileiras, e a informação coletada incluiu o SF-36 como uma medida de qualidade de vida relacionada à saúde. Isto proveu uma oportunidade única para desenvolver dados normativos ajustados por idade e sexo para a população brasileira. RESULTADOS: Os escores dos homens brasileiros foram maiores que os das mulheres nos oito domínios e duas medidas componentes do SF-36. Os brasileiros tiveram pontuação mais baixa que seus respectivos contrapartes internacionais em quase todos os domínios e medidas componentes do SF-36, à exceção do estado geral de saúde (USA), dor (GB) e vitalidade (Austrália, USA e Canadá). CONCLUSÃO: As diferenças nos escores do SF-36 entre grupos etários, sexo e países confirmam que as normas brasileiras são necessárias para propósitos comparativos. Os dados serão úteis para avaliar o status de saúde da população em geral e dos pacientes, e o efeito das intervenções na qualidade de vida relacionada à saúde. .

El problema del cumpleaños, una generalización: an overview / the birthday problem

El problema del cumpleaños, en el contexto clásico, se resuelve asumiendo una distribución de probabilidades uniforme discreta de los nacimientos. El propósito de este artículo es resolver el mismo problema bajo una distribución de probabilidades discreta arbitraria, y demostrar que bajo la distribución uniforme discreta, la probabilidad de que dos o más personas cumplan años en el mismo día es subestimada.

In the classic context, the birthday problem is solved assuming a discrete uniform probability distribution of births. The main purpose of this paper is to solve the birthday problem through an arbitrary discrete probability distribution and to prove that using discrete uniform distribution, probability of two or more people's birthday at the same date is underestimated.

Influence of random setup error on dose distribution / 中华放射肿瘤学杂志

Objective To investigate the influence of random setup error on dose distribution in radiotherapy and determine the margin from ITV to PTV. Methods A random sample approach was used to simulate the fields position in target coordinate system. Cumulative effect of random setup error was the sum of dose distributions of all individual treatment fractions. Study of 100 cumulative effects might get shift sizes of 90%dose point position. Margins from ITV to PTV caused by random setup error were choosen by 95% probability. Spearman's correlation was used to analyze the influence of each factor. Results The average shift sizes of 90%dose point position was 0.62,1.84,3.13,4.78,6.34 and 8.03 mm if random setup error was 1,2,3,4,5 and 6 mm,respectively. Univariate analysis showed the size of margin was associated only by the size of random setup elror. Conclusions Margin of ITV to PTV is 1.2 times random setup error for head-and-neck cancer and 1.5 times for thoracic and abdominal cancer. Field size, energy and target depth. unlike random setup error, have no relation with the size of the margin.

Clinical Application of Microcomputer Optometer / 医疗卫生装备

Objective To discuss the principle and clinical application of microcomputer optometer.Methods The optometer is composed of singlechip,handle and LCD.The eyesight is examined by selecting exposure of random sample eye-chart mark 'E' within direction keys on the handle.Results The optometer has the merits of simple manipulation,exact result,small cubage,AC/DC power supply and so on.Besides,it prevents the testee from remembering eye-chart.Conclusion The optometer can be extensively used in hospital,school,every work unit or even family.