National health surveys: overview of sampling techniques and data collected using complex designs / Encuestas nacionales de salud: descripción general de las técnicas de muestreo y los datos recopilados por diseños complejos / Inquéritos nacionais de saúde: visão geral sobre técnicas de amostragem e dados coletados por desenhos complexos

Abstract This article aimed to present an overview of national health surveys, sampling techniques, and components of statistical analysis of data collected using complex sampling designs. Briefly, surveys aimed at assessing the nutritional status of Brazilians and maternal and child health care were described. Surveys aimed at investigating access to and use of health services and funding, those aimed at surveillance of chronic noncommunicable diseases and associated behaviors, and those focused on risk practices regarding sexually transmitted infections were also addressed. Health surveys through social networks, including online networks, deserved specific attention in the study. The conclusion is that the development of health surveys in Brazil, in different areas and using different sampling methodologies, has contributed enormously to the advancement of knowledge and to the formulation of public policies aimed at the health and well-being of the Brazilian population.

Resumen Este estudio tuvo como objetivo presentar una descripción de las encuestas nacionales de salud, las técnicas de muestreo y los componentes del análisis estadístico de diseños de muestreo complejos. Brevemente, se describieron encuestas destinadas a evaluar el estado nutricional y la atención a la salud materno-infantil. También se abordaron las encuestas dirigidas a investigar el acceso y uso de los servicios de salud y el financiamiento, las dirigidas a la vigilancia de las enfermedades crónicas no transmisibles y comportamientos asociados, y las enfocadas a las prácticas de riesgo para las infecciones de transmisión sexual. Las encuestas de salud a través de las redes sociales, incluidas las virtuales, merecieron atención específica en el estudio. Se concluye que el desarrollo de encuestas de salud en Brasil ha contribuido enormemente para el avance del conocimiento y para la formulación de políticas públicas dirigidas a la salud y el bienestar de la población brasileña.

Resumo O artigo teve por finalidade apresentar um panorama dos inquéritos nacionais de saúde, técnicas de amostragem e componentes da análise estatística de dados coletados por desenhos complexos de amostragem. Foram descritos, brevemente, os inquéritos dirigidos à avaliação do estado nutricional dos brasileiros e da atenção à saúde materno-infantil. Inquéritos voltados à investigação do acesso, utilização dos serviços e financiamento da saúde, aqueles dedicados à vigilância das doenças crônicas não transmissíveis e comportamentos associados e os focados nas práticas de risco às infecções sexualmente transmissíveis foram também abordados. As pesquisas de saúde por redes sociais, incluindo as virtuais, mereceram atenção específica. Conclui-se que o desenvolvimento de inquéritos de saúde no Brasil, em diferentes áreas e por distintas metodologias de amostragem, contribuiu enormemente para o avanço do conhecimento e a formulação de políticas públicas dirigidas à saúde e bem-estar da população brasileira.

Algunas consideraciones para el cálculo del tamaño muestral en investigaciones de las Ciencias Médicas / Some considerations for the calculation of the sample size in Medical Sciences research

RESUMEN El proceso de formación y superación permanente o continuada de los profesionales, como un principio de la Educación Médica, se articula con la integración docencia, asistencia e investigación. Para responder a las exigencias de la actividad investigativa, la búsqueda y el tratamiento de la información requiere de un estudio estadístico para que aflore la cualidad desde el análisis cuantitativo; para ello, es importante considerar que en todos los estudios de esta magnitud, la población total se hace muy engorrosa, cara y lenta, por lo que se deben emplear técnicas de muestreo para obtener información significativa con el uso de menos recursos y menor tiempo. El objetivo del presente trabajo es reflexionar sobre el uso del muestreo en las ciencias médicas. Se expone la fórmula del muestreo para media y varianza conocidas, se da una técnica para encontrar el número de elementos de la muestra inicial cuando no se tienen conocimientos previos de media y varianza; se estudia el muestreo aleatorio simple de proporciones con las probabilidades de éxito y fracaso p y q respectivamente, explicándose el caso cuando se tiene p = q = 0.5 para la obtención de un tamaño de la muestra máximo.

ABSTRACT The objective of this paper is to reflect some considerations on the use of sampling in health sciences, based on the need for professionals in these sciences to familiarize themselves with scientific research in their area of knowledge, from a scientific perspective, that makes it possible to investigate the health problems that are constantly developing. The process of Permanent and Continuous Training and Improvement of professionals, as a principle of Medical Education, is articulated with that of Teaching - Assistance and research, the search and treatment of information in this area of scientific knowledge, requires of a statistical study that emerges the quality from the quantitative analysis, for this, it is important to consider that in all studies of this magnitude, the total population becomes very cumbersome, expensive and slow, so sampling techniques should be used to Obtain meaningful information with the use of less resources and less time. The sampling formula for known mean and variance is presented, a technique is given to find the number of elements of the initial sample when there is no prior knowledge of mean and variance, simple random sampling of proportions with the probabilities of success is studied and failure p and q respectively, explaining the case when you have p = q = 0.5 to obtain a maximum sample size.

Nomophobia: mobile phone dependence among students of a medical college in Central Odisha, India

Background: Nomophobia, stands for “no mobile phone phobia". The tremendous increase in mobile phone usage among youngsters has led to negative impact on their mental health status. Current study aims at finding out the prevalence of nomophobia (mild, moderate, and severe), various health related conditions and independent risk factors of severe nomophobia among medical students of a tertiary care college and Hospital of Central Odisha.Methods: A cross sectional study carried out among 450 students of a medical college of Central Odisha. Simple random sampling was done. Predesigned pretested questionnaire including Nomophobia questionnaire (NMP-Q) was used for data collection. Data was analyzed using SPSS and logistic regression was used to evaluate the independent risk factors of severe nomophobia.Results: Out of 450 students, 246 (54.6%) were boys and rest were girls. Nomohobia was universally present and students suffering from mild, moderate and severe form of nomophobia comprised of 33 (7.3%), 327 (72.7%) and 90 (20%) respectively. Independent risk factors of severe nomophobia were fourth year of study and above (aOR=2.69), use of costly handsets (aOR=4.56), monthly bill of more than rupees 500 for cell phone use (aOR=6.09) and anxiousness of staying updated with news all the time (aOR=4.86).Conclusions: Nomophobia is a highly prevalent condition among the medical students found across age groups, gender and socio-economic status which depends on phone usage. It is recommended that screening and proper counselling should be available in order to decrease the burden and create awareness about nomophobia among the medical students.

Application of a simple random sampling method on surveys at the community level / 中华流行病学杂志

Objective To study the feasibility of a simple random sampling on surveys at the community level and to evaluate the quality of samples under survey.Methods A simple random sample of households was taken,based on the electronic listings of community households from Gongshu and Xiacheng districts of Hangzhou city.One of the adults aged 18 to 64 years in the sampled households was identified with KISH method to finish a questionnaire survey.More than 500 people from the sample size was required in each district.Results Of 950 sampled households in Xiacheng district,511 (53.8%) finished the survey while 506 (36.7%) out of the 1380 sampled households in Gongshu district did.The proportions of non-response due to the following reasons as:none with eligible age in the households,relocation of the original household,mass relocation of the community,and errors in the household listings etc.were 38.3% and 43.5% respectively,in the two districts.Proportions attributed to non-response and refusal to response of sampled household or individual were 8.0% and 19.9% respectively.No statistical significant differences in age and gender were found between the surveyed samples and the population in the sampled households,or in gender between the populations in the sampled households and in Hangzhou city.However,the population in the sampled households showed a more aging population structure than the population in Hangzhou city.Conclusion In a geographically limited area,using a simple random sampling method to do the survey is feasible,based on the electronic listings of household.Enough time spent during the household visit guarantees the interviewers to get a representative sample of the sampling frame.There is an urgent need for the timeliness,completeness and accuracy of electronic household listings to be improved.