Medidas de frecuencia en epidemioloxía

Titulación: Licenciatura en Medicina e Cirurxía -- Materia: Epidemioloxía Xeral e Demografía SanitariaA presente Unidade Didáctica vai dirixida aos alumnos do terceiro ano da Licenciatura de Medicina, da disciplina “Epidemioloxía xeral e Demografía sanitaria”. Con ela preténdese contribuír á aprendizaxe máis autónoma do alumnado, de xeito que lles sirva de guía dun dos temas do programa, quizais un dos máis importantes, que supón a introdución ás ferramentas de medida dos fenómenos epidemiolóxicos estudados en Epidemioloxía, Saúde Pública e nas Ciencias da Saúde en xeral: as vulgarmente chamadas “taxas”, termo que adoita englobar varios destes instrumentos cuxa utilización non sempre é a máis acaída, adoitando confundilas e intercambialas de xeito incorrecto. A definición dos diferentes conceptos, a súa formulación matemática –aspecto frecuentemente máis complicado para persoas esquecidas dos rudimentos matemáticos mais sinxelos– e a aplicación de cada un dos índices de medida para resolvermos exercicios apropiados a cada un deles constituirán os contidos desta unidade.Universidade de Santiago de Compostela. Servizo de Normalización Lingüístic

Riesgos vinculados a la exposición al radón

They discuss the different scientific evidence that radon and its short half-life descendants are responsible for the appearance of a considerable number of lung cancers among the exposed population in homes and public buildings (occupational exposure). It also draws a small glimpse at the road traveled by this knowledge and acceptance difficult administrations in many countries and, in particular, of Spain, as well as the various investigations that the team do Galego Radon and Radon Laboratory from Galicia, the area of Public Health, University of Santiago de Compostela (USC), are contributing to scientific knowledge. Finally, they appreciate the few legislative initiatives on the problem in Spain.Se comentan las diferentes evidencias científicas de que el radón y sus descendientes de vida media corta son responsables de la aparición de un número no desdeñable de cánceres de pulmón entre la población expuesta en domicilios y edificios públicos (exposición laboral). Asimismo, se traza una pequeña aproximación al camino recorrido por este conocimiento y su difícil aceptación por parte de las diferentes Administraciones de numerosos países y, en concreto, de España, así como las diversas investigaciones que el Grupo Galego do Radon y el Laboratorio de Radón de Galicia, del Área de Salud Pública, de la Universidad de Santiago de Compostela, llevan aportando a ese conocimiento científico. Por último, se valoran las escasas iniciativas legislativas sobre el problema en España

El radón: ¿riesgo para la salud?

Radon (Rn222) is a radioactive noble gas whose origin is Radium (Ra226) when it emits an alpha particle (two protons and two neutrons) or a helium nucleus. Rn222 transforms in another radioactive element (Po218) when an alpha particle is emitted. Its carcinogenic effect on the lung was discovered various decades ago, first on uranium miners and later on general population exposed at home to residential radon. The main factor influencing radon concentration in dwellings is the uranium content of the subsoil, since uranium is the first element of the radioactive disintegration chain where radon appears. Geological risk areas of Spain due to their granite and therefore uranium content are Galicia, the Northwest and the West of Spain. Numerous countries of Europe and America have enforced legislation focused to protect population and reduce radon concentration in order to prevent lung cancer appearance. These laws comprise public buildings and private homes. Since the late 80s, alpha radiation generated by radon and its short-life descendents has been classified as carcinogenic agents by the International Agency for Research on Cancer (Lyon, 1988) and the National Research Council (BEIR IV, 1988).El radón (Rn222) es un gas noble radiactivo que procede directamente del radio (Ra226) cuando este emite una partícula alfa (dos protones y dos neutrones) o núcleo de helio, y que a su vez se transforma en otro elemento radiactivo (Po218) al desprenderse de otra partícula alfa. Desde hace varias décadas se conoce su efecto como factor de riesgo del cáncer primario pulmonar, primero en mineros del uranio y posteriormente en la población general expuesta al radón residencial en hogares construidos sobre suelos de rocas ricas en uranio (U238), elemento inicial de la cadena de degradación radiactiva de la que procede el radón. Áreas geológicamente constituidas por granitos o pizarras, como son las de gran parte de Galicia y todo el noroeste y oeste de la península ibérica, han sido catalogadas como de alto riesgo de exhalación de radón al interior de edificios y domicilios. En numerosos países de América y Europa existen desde hace varios lustros, políticas de prevención del cáncer pulmonar en aquellas zonas de riesgo basadas en programas de reducción de radón en los domicilios y edificios públicos. Desde finales de los años 80, la radiación alfa procedente del radón y sus descen- dientes de vida media corta han sido clasificados como agentes cancerígenos por la Internacional Agency of Research on Cancer (Lyon, 1988) y el Nacional Research Council (BEIR IV, 1988), constituyendo la segunda causa de cáncer pulmonar después del tabaco, y responsable del 10 al 15 % de todas las muertes por esa neoplasia. Estudios realizados en Galicia confirman esta evidencia, con riesgos de 2 a 3 en expuestos a concentraciones del gas en domicilios y la responsabilidad directa del 9% de todos los casos de cáncer pulmonar del área estudiada y una interacción radón/tabaco que multiplica por 45 el riesgo

Radon Exposure and Neurodegenerative Disease

Background: To carry out a systematic review of scientific literature about the association between radon exposure and neurodegenerative diseases. Methods: We performed a bibliographic search in the following databases: Pub med (Medline), Cochrane, BioMed Central and Web of Science. We collected the data by following a predetermined search strategy in which several terms werecombined. After an initial search, 77 articles were obtained.10 of which fulfilled the inclusion criteria. Five of these 10 studies were related to multiple sclerosis (MS), 2 were about motor neuron diseases (MND), in particular amyotrophic lateral sclerosis (ALS) and 3 were related to both Alzheimer's disease (AD) and Parkinson's disease (PD). Results: The majority of the included articles, suggested a possible association between radon exposure and a subsequent development of neurodegenerative diseases. Some of the studies that obtained statistically significant resultsrevealed a possible association between radon exposure and an increase in MS prevalence. Furthermore, it was also suggested that radon exposure increases MND and AD mortality. Regarding AD and PD, it was observed that certainde cay products of radon-222 ((222)Rn), specifically polonium-210 ((210)Po) and bismuth-210 ((210)Bi), present a characteristic distributionpattern within the brain anatomy. However, the study with the highest scientific evidence included in this review, which investigated a possible association between the concentration of residential radon gas and the MS incidence, revealed no significant results. Conclusions: It cannot be concluded, although it is observed, that there is a possible causal association between radon exposure and neurodegenerative diseases. Most of the available studies are ecological so, studies of higher statistical evidence are needed to establish a causal relationship. Further research is needed on this topic

Controles poblaciones frente a controles hospitalarios: ¿son comparables?

Objective:To compare whether there are differences amonghospital and population controls. Methods:Two case-control studies were conducted on lungcancer risk factors in the Santiago de Compostela Public Health District. Whereas one used randomly chosen census-based population controls, the other used consecutive hos-pital controls that went to the reference hospital for non-smo-king-related trivial interventions. The differences were analyzedusing logistic regression. The dependent variable was type ofcontrol (hospital or population). Results:Hospital controls had a similar tobacco habit thanpopulation controls, but consumed more alcohol. For those con-suming more than 50 ml daily, the risk of being a hospital con-trol was 4.83 (95%CI: 2.55-9.14). Conclusions:There may be some differences between hos-pital and population-based controls, which must be taken intoaccount in the design of case-control studies. It is necessaryto ascertain whether such differences are reproduced at othergeographic locations and whether they can affect estimationof exposure-diseaseObjetivo:Comparar si hay diferencias entre los controles po-blacionales y los hospitalarios.Métodos:Se llevaron a cabo dos estudios de casos y con-troles sobre factores de riesgo de cáncer de pulmón en el ÁreaSanitaria de Santiago de Compostela. En uno de los estudioslos controles fueron seleccionados aleatoriamente entre la po-blación general, y en el otro los controles hospitalarios fue-ron incluidos de manera consecutiva entre los individuos queacudían al hospital por intervenciones quirúrgicas banales norelacionadas con el consumo de tabaco. Las diferencias fue-ron analizadas mediante regresión logística. La variable de-pendiente fue el tipo de control (hospitalario o poblacional).Resultados:Los controles hospitalarios y los poblacionalestenían un hábito tabáquico similar, pero los controles hospi-talarios consumían más alcohol. Para los que consumían másde 50 ml al día, el riesgo de ser un control hospitalario fuede 4,83 (intervalo de confianza del 95%: 2,55-9,14).Conclusiones:Podría haber algunas diferencias entre los con-troles poblacionales y los hospitalarios que deberían tenerseen cuenta cuando se diseñe un estudio de casos y contro-les. Es necesario saber si esas diferencias son similares enotras áreas geográficas y si podrían afectar a la estimaciónde las medidas de efecto entre exposición y enfermedadThis work has been partly funded by two investigationgrants, one from the Fondo de Investigaciones Sanitarias (FIS)(Health Research Fund) (grant FIS 92/0176) and the GalicianRegional Health Authority (grant XUGA 91010)S

Radônio residencial e câncer de pulmão: um estudo de coorte na Galícia, Espanha

Case-control studies show an association between residential radon and lung cancer. The aim of this paper is to investigate this association through a cohort study. We designed an ambispective cohort study using the Galician radon map, Spain, with controls drawn from a previous case-control study. Subjects were recruited between 2002 and 2009. The data were cross-checked to ascertain lung cancer incidence and then analysed using a Cox regression model. A total of 2,127 subjects participated; 24 lung cancer cases were identified; 76.6% of subjects were drawn from the radon map. The adjusted hazard ratio was 1.2 (95%CI: 0.5-2.8) for the category of subjects exposed to 50Bq/m3 or more. This risk rose when subjects from the case-control study were analyzed separately. In conclusion, we did not observe any statistically significant association between residential radon exposure and lung cancer; however, it appears that with a sample of greater median age (such as participants from the case-control study), the risk of lung cancer would have been higher.Los estudios de casos y controles muestran una asociación entre el radón residencial y el cáncer de pulmón. El objetivo del artículo fue investigar esa asociación a través de un estudio de cohorte. Proyectamos un estudio de cohorte ambispectivo, utilizando el mapa de radón de Galicia, España, con los controles obtenidos de un estudio anterior de casos y controles. Los individuos fueron reclutados entre 2002 y 2009. Los datos fueron verificados para confirmar la incidencia de cáncer de pulmón y después analizados con un modelo de regresión de Cox. Participaron un total de 2.127 individuos; se identificaron 24 casos de cáncer de pulmón; un 76,6% de los individuos fueron obtenidos a través del mapa de radón. El hazard ratio ajustado era 1,2 (IC95%: 0,5-2,8) para la categoría de individuos expuestos a 50Bq/m3 o más. El riesgo aumentó cuando los individuos del estudio de casos y controles fueron analizados separadamente. En conclusión, no se observó una asociación estadísticamente significativa entre exposición al radón residencial y cáncer de pulmón; sin embargo, parece que con una muestra con una media de edad más elevada (tales como los participantes del estudio de casos y controles), el riesgo de cáncer de pulmón habría sido más alto.Estudos de casos e controles mostram uma associação entre radônio residencial e câncer de pulmão. O artigo teve como objetivo investigar essa associação através de um estudo de coorte. Projetamos um estudo ambispectivo coorte, utilizando o mapa de radônio da Galícia, Espanha, com os controles obtidos de um estudo anterior de casos e controles. Os indivíduos foram recrutados entre 2002 e 2009. Os dados foram verificados para confirmar a incidência de câncer de pulmão e depois analisados com um modelo de regressão de Cox. Participaram um total de 2.127 indivíduos; foram identificados 24 casos de câncer de pulmão; 76,6% dos indivíduos foram obtidos através do mapa de radônio. O hazard ratio ajustado era 1,2 (IC95%: 0,5-2,8) para a categoria de indivíduos expostos a 50Bq/m3 ou mais. O risco aumentou quando os indivíduos do estudo de casos e controles foram analisados separadamente. Em conclusão, não foi observada associação estatisticamente significativa entre exposição ao radônio residencial e câncer de pulmão; entretanto, parece que com uma amostra com mediana de idade mais elevada (tais como os participantes do estudo de casos e controles), o risco de câncer de pulmão teria sido mais alto.This work was supported by the Carlos III Institute of Health, Ministry of Science & Innovation under grant PI10/00296 and PI03/1248. Galician Regional Authority (Xunta de Galicia) under grant PGIDT01MAM20801PR. Part of this work has been performed during a Fulbright grant for Senior Researchers awarded to Alberto Ruano-Ravina at Brown University (Providence, Rhode Island, USA) (REF PRX14/00365)S

COPD prevalence and hospital admissions in Galicia (Spain). An analysis using the potential of new health information systems

Introduction and objectives: Chronic obstructive pulmonary disease (COPD) is a major public health problem. The aim of this study was to ascertain the prevalence of COPD and whethersuch prevalence was positively or negatively associated with COPD admissions, using all thedata of a regional health care system.Materials and methods: We designed a descriptive cross-sectional study which included all sub-jects aged over 45 years, diagnosed with COPD in primary care in 2013. We also calculated the number of such patients who had a record of hospital admissions due to this disease. COPDprevalence and incidence of admissions were calculated. Poisson regression models were thenused to analyse the association between cases with diagnosis of COPD and admissions due toCOPD, by sex, adjusting for socio-demographic variables and distance to hospital. Sensitivitysubanalyses were performed by reference to the respective municipal rurality indices.Results: Median municipal prevalence of COPD was 5.29% in men and 2.19% in women. Amongpatients with COPD, 28.22% of men and 16.00% of women had at least one hospital admission.The relative risk of admission per unit of the standardised prevalence ratio was 0.37 (95% CI0.34---0.41) for men and 0.39 (95% CI 0.34---0.45) for women.Conclusions: There is a significant negative association between COPD prevalence and hospital admissions due to this disease. The proportion of admissions is lower in municipalities lyingfurthest from hospitals. There is considerable municipal variability in terms of COPD preva-lence and proportion of admissions. In-depth attention should be given to disease-managementtraining programmesS

Genetic susceptibility, residential radon, and lung cancer in a radon prone area

INTRODUCTION: Radon exposure has been classified as the second cause of lung cancer, after tobacco, and the first in never smokers. GSTM1 and GSTT1 genes deletion increase the risk of lung cancer. We aim to know whether the risk of lung cancer because of residential radon is modulated by these genetic polymorphisms. METHODS: Hospital-based, case-control study where cases had confirmed lung cancer. Cases and controls did not have previous neoplasm and were older than 30. Controls attended hospital for noncomplex surgery. We analyzed the results for the whole sample and separately for never/light smokers and moderate/heavy smokers. RESULTS: Seven-hundred and ninety-two participants were analyzed. GSTM1 and GSTT1 deletion conferred an odds ratio (OR) of 1.38 (95% confidence interval [CI] 0.93-2.04) and 1.13 (95% CI 0.70-1.82), respectively. Individuals with GSTM1 present and residential radon concentrations higher than 148 Bq/m had an OR of 1.48 (95% CI 0.73-3.00), whereas those with GSTM1 deleted had an OR of 2.64 (95% CI 1.18-5.91) when compared with participants with GSTM1 present and radon concentrations below 50 Bq/m3. Similar results were observed for GSTT1 deletion. These results were basically the same for the moderate/heavy smokers' subgroup. CONCLUSIONS: The absence of GSTM1 and GSTT1 genes increases the risk of lung cancer because of radon exposure. These genes might modulate the carcinogenic pathway of alpha radiation. Further studies are warranted analyzing this association in never smokers

Residential Radon in Manizales, Colombia: Results of a Pilot Study

Radon is a colorless, odorless, and tasteless noble gas, causally related with the onset of lung cancer. We aimed to describe the distribution of radon exposure in the municipality of Manizales, Colombia, in order to estimate the population’s exposure and establish the percentage of dwellings that surpass reference levels. A cross-sectional study representing all geographical areas was carried out by measuring indoor radon concentrations. Participants answered a short questionnaire. Alpha-track type radon detectors were installed in all residences for six months. The detectors were subsequently processed at the Galician Radon Laboratory, an accredited laboratory at the University of Santiago de Compostela. A total of 202 homes were measured. Seventy-seven percent of the sampled houses were three stories high, their median age was 30 years, and half were inhabited by three people or fewer. For most dwellings, the building materials of walls and flooring were brick and covered cement, respectively. Results showed a geometric mean of radon concentration of 8.5 Bq/m3 and a maximum value of 50 Bq/m3. No statistically significant differences were found either between the geometric mean of the dwelling’s site, the height at which detectors were placed inside the home, or the wall and flooring materials, or between mean 222Rn concentrations in rural and urban areas. No dwelling surpassed the 222Rn reference level established by the WHO. This study shows that residential radon levels in Manizales, Colombia, seem to be low, though a more in-depth approach should be carried out. Despite these results, it is essential to create a national radon program and establish a radon concentration reference level for Colombia in line with international recommendationsThis study was funded by the Galician Radon Laboratory from the University of Santiago de Compostela (School of Medicine) and by the Institute of Health Research and Vicerrectorate of Research and post-graduate studies REF 0340220) of the University of Caldas (Manizales, Colombia)S

Quantifying indoor radon levels and determinants in schools: a case study in the radon-prone area Galicia–Norte de Portugal Euroregion

Radon is a carcinogenic compound, and is particularly concerning in the education sector, where children and teachers may be exposed even longer than at home. Thus, this study intended to characterise radon in the indoor air of scholar environments in different provinces/districts of the Euroregion Galicia–Norte de Portugal. With a pioneering approach, this study evaluated the influence of specific factors/characteristics (location, type of management, construction material, season and floor within the building) and quantified their relative contribution to indoor radon levels. Radon was continuously monitored in 416 classrooms from school buildings located in urban and rural sites from different provinces/districts both in the regions of Galicia (A Coruña and Lugo provinces) and Portugal (Porto and Bragança districts), considering rooms for different age groups (from nursery schools to universities). Single and multivariate linear regression models were built considering the radon concentrations as the outcome variable and different room/building characteristics as predictor variables. Mean and median radon concentrations were 332 Bq·m−3 and 181 Bq·m−3, respectively. The radon concentrations observed are a public health concern, as almost 1/3 of the places monitored exceeded the reference limit value of the European legislation (300 Bq·m−3). Moreover, around 50 % of the indoor levels measured could be attributed to room/building characteristics: the building's location and the main construction material, as well as the occupants' age group, the floor within the building and the school's type of management (public/private). This study concluded that radon testing is needed in all school buildings and classrooms without exceptions. Thus, public administrations are urged to dedicate funds for testing, mitigation and public dissemination initiatives in schools. A special protocol for radon sampling in school buildings should also be developedThis work was financially supported by: LA/P/0045/2020 (ALiCE) and –(LEPABE) funded by national funds through FCT/MCTES (PIDDAC); competitive scholarship from Fundación Prevent (Beca I + D en PRL). PTBS Branco thanks the Portuguese Foundation for Science and Technology (FCT) for the financial support of his work contract through the Scientific Employment Stimulus – Individual Call – 2022.05461.CEECIND. The funding sources did not have any involvement in study design; in the collection, analysis and interpretation of data; in the writing of the report; nor in the decision to submit the article for publicationS