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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 developed

El objetivo principal de esta tesis es determinar el rol que el consumo de alcohol, frutas y verduras tienen en el desarrollo de CP en nunca fumadores. Se utilizó una muestra poblacional derivada de la agrupación de estudios multicéntricos de casos y controles. Los resultados se ajustaron por edad, sexo, nivel de estudios, tabaquismo pasivo y radón en domicilio. Resultados: a) el consumo de vino y bebidas espirituosas son un factor de riesgo para el CP con unas OR de 2.20 (IC 95%: 1.12 -4.35) y 1.90 (IC 95%: 1.13 -3.23) respectivamente, b) hay efecto protector para el consumo de naranjas (OR 0.55; 95%IC: 0.37-0.80), kiwis (OR 0.67; 95%IC: 0.46-0.95), nabos (OR 0.48; 95%IC: 0.34-0.66), berza gallega (OR 0.70; 95%IC: 0.51-0.97) y brócoli (OR 0.55; 95%IC: 0.35-0.83), c) la ingesta de tomates, zanahorias y patatas suponen un factor de riesgo con OR e IC de 1.95 (IC 95%: 1.20-3.20), 1.75 (IC 95%: 1.01-3.04) y 1.84 (IC95%: 1.11-3.08), respectivamente.

Lung cancer has the highest cancer mortality rate in developed countries. The principal risk factor for lung cancer is tobacco use, with residential radon being the leading risk factor among never smokers and the second among ever smokers. We sought to estimate mortality attributable to residential radon exposure in Spain and its Autonomous Regions, with correction for dwelling height and differentiation by tobacco use. We applied a prevalence-based method for estimating attributable mortality. For estimations, we considered exposure to radon in the different Autonomous Regions corrected for dwelling height, using the National Statistics Institute Housing Census and prevalence of tobacco use (never smokers, smokers and ex-smokers). The results showed that 3.8% (838 deaths) of lung cancer mortality was attributable to radon exposure of over 100 Bq/m3, a figure that rises to 6.9% (1,533 deaths) when correction for dwelling height is not performed. By Autonomous Region, the highest population attributable fractions, corrected for dwelling height, were obtained for Galicia, Extremadura, and the Canary Islands, where 7.0, 6.9, and 5.5% of lung cancer mortality was respectively attributable to radon exposure. The greatest part of the attributable mortality occurred in men and among smokers and ex-smokers. Residential radon exposure is a major contributor to lung cancer mortality, though this contribution is highly variable among the different territories, indicating the need for targeted prevention policies. Correction of estimates for dwelling height is fundamental for providing reliable estimates of radon-attributable mortality

El cáncer de pulmón es un grave problema para la salud pública, debido a su elevada mortalidad. Uno de sus tipos es el cáncer de célula pequeña (CPCP), que significa en torno al 10-15% de todos los casos. Es el tipo histológico más letal. El principal factor de riesgo es el tabaco, pero existen pocas investigaciones sobre el efecto del radón en el cáncer de pulmón de célula pequeña. Debido a su relativa baja frecuencia, no hay muchas investigaciones sobre la etiología del CPCP y su asociación directa con elevadas concentraciones de radón residencial no ha sido estudiada en profundidad. Esta investigación pretende analizar el posible vínculo etiológico entre la concentración de radón residencial y el desarrollo de CPCP. Para ello se diseñó un estudio multicéntrico de casos y controles de base hospitalaria, en el que participaron 9 centros hospitalarios del norte de España y Portugal, en el que se incluyeron casos diagnosticados de CPCP entre septiembre de 2015 y agosto de 2019. Se analizó el riesgo de CPCP en relación con la concentración de radón en el domicilio y la posible sinergia entre radón y consumo de tabaco. El resultado más relevante es la demostración de que existe una asociación estadísticamente significativa entre los sujetos expuestos a concentraciones de radón superiores a los niveles recomendados por la Agencia de Protección Ambiental Norteamericana (148 Bq/m3) con una Odds Ratio de 2.08 (IC 95%: 1.03 - 4.39) frente a aquellos con concentraciones de radón residencial inferiores a 50 Bq/m3. Una modelización adicional indica que la relación existente entre radón y CPCP puede asumirse como lineal. Existe además una sinergia cercana a la significación estadística con el consumo de tabaco.

El cáncer de pulmón (CP) en nunca fumadores es una entidad clínica distinta. Es más frecuente en mujeres, en estadio avanzado, con presencia de mutaciones y si su histología es adenocarcinoma. No parece existir relación entre la exposición a radón y las características al diagnóstico aunque se sugiere cierta relación entre concentraciones elevadas (> 1.000 Bq/m3) y el CP de célula pequeña en estadio extenso. La supervivencia del CP descrita en la literatura para los nunca fumadores parece mayor que la de los fumadores. Los datos de esta tesis parecen confirman la mayor supervivencia de los pacientes nunca fumadores. La supervivencia mediana de los nunca fumadores fue mayor en los pacientes de menor edad, con adenocarcinoma, presencia de mutaciones en genes diana y estadio al diagnóstico más precoz. Los casos con exposición a concentraciones de radón residencial superiores a 300 Bq/m3 obtuvieron una peor supervivencia a 3 y 5 años del diagnóstico. Por otro lado, la supervivencia a 5 años del diagnóstico de los pacientes con CP no parece estar influida por polimorfismos en genes que participan en las vías de reparación del ADN, excepto para el grupo de pacientes que reciben radioterapia o quimio-radioterapia y presentan la mutación ERCC1 rs3212986. En aquellos casos que reciben estos tratamientos se observa una mayor toxicidad ante la presencia de mutaciones en los genes OGG1 rs1052133 (CG) y ERCC1 rs11615.

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 recommendations