Trace element contents in fine particulate matter (PM2.5) in urban school microenvironments near a contaminated beach with mine tailings, Chañaral, Chile.

Air quality in schools is an important public health issue because children spend a considerable part of their daily life in classrooms. Particulate size and chemical composition has been associated with negative health effects. We studied levels of trace element concentrations in fine particulate matter (PM2.5) in indoor versus outdoor school settings from six schools in Chañaral, a coastal city with a beach severely polluted with mine tailings. Concentrations of trace elements were measured on two consecutive days during the summer and winter of 2012 and 2013 and determined using X-ray fluorescence. Source apportionment and element enrichment were measured using principal components analysis and enrichment factors. Trace elements were higher in indoor school spaces, especially in classrooms compared with outdoor environments. The most abundant elements were Na, Cl, S, Ca, Fe, K, Mn, Ti, and Si, associated with earth's crust. Conversely, an extremely high enrichment factor was determined for Cu, Zn, Ni and Cr; heavy metals associated with systemic and carcinogenic risk effects, whose probably origin sources are industrial and mining activities. These results suggest that the main source of trace elements in PM2.5 from these school microenvironments is a mixture of dust contaminated with mine tailings and marine aerosols. Policymakers should prioritize environmental management changes to minimize further environmental damage and its direct impact on the health of children exposed.

Significancia clínica y significancia estadística. ¿Qué es más significativo? / Clinical significance and statistical significance. What is more significant?

Una de las dificultades más comunes que enfrentan los lectores de artículos del área de la biomedicina y epidemiología es la interpretación del término "significativo". El término "estadísticamente significativo" a menudo se malinterpreta como un resultado "clínicamente significativo". La confusión surge del hecho de que muchas personas equiparan "significativo" con su significado literal de "importante", sin embargo, la significación estadística cuantifica la probabilidad de que los resultados de un estudio se deban al azar, mientras que la significancia clínica refleja la importancia práctica o relevancia en el contexto de la atención médica o práctica clínica. Este artículo aborda la diferencia entre la significación estadística y la relevancia o importancia clínica en la interpretación de los resultados de una investigación biomédica.

One of the most common difficulties faced by readers of articles in the area of biomedicine and epidemiology is the interpretation of the term "significant". The term "statistically significant" is often misinterpreted as a "clinically significant" result. Confusion arises from the fact that many people equate "significant" with its literal meaning of "important," however, statistical significance quantifies the probability that the results of a study are due to chance, while clinical significance reflects the practical importance or relevance in the context of health care or clinical practice. This article addresses the difference between statistical significance and clinical relevance or importance in the interpretation of biomedical research results.

[Temporal trend of premature mortality for external causes in Chile between 1997-2014]. / Evolución temporal de la mortalidad prematura por causas externas en Chile entre 1997-2014.

OBJECTIVE: Currently, there is a change in the causes of mortality towards noncommunicable diseases and external causes. However, there are no updated studies on the trend of premature mortality due to external causes (PMEC) in Chile and the underlying sociodemographic variables. The objective of this study was to evaluate the trend of PMEC in Chile between 1997-2014 and analyze its distribution according to sociodemographic variables. METHODS: Ecological mixed study. The cause of death and demographic data of mortality databases and official population estimates of the government of Chile were used. The PMEC and main subcauses (traffic accidents, self-inflicted injuries and aggressions) were considered in the population between 15-64 years. Annual crudes and adjusted rates (direct method) were estimated between 1997-2014. The trend of adjusted rates was evaluated using Prais-Winsten regression. RESULTS: There were 102.559 deaths from external causes during the period studied (22.1% of total mortality). The cases were concentrated in men (85.3%), in the group of 25-44 years (44.8%) and at the basic instruction level-without instruction (48,4%). The PMEC trend decreased significantly in general population (ß=-1.18x100,000 inhab., 95%CI: -1.58,-0.78) and men (ß=-2.25x100,000 inhab. 95%CI: -2.79;-1.7). In women, there were no significant changes in PMEC, however an increase in PM due to aggressions was observed (ß=0.03x100,000 inhab. 95%CI: 0.002,0.05). CONCLUSIONS: During the study period, a decrease in MPCE could be observed, especially that caused by traffic accidents. However, it has not been possible to reduce in women, alerting the increase in MP due to aggressions.

OBJETIVO: Actualmente existe un desplazamiento de las causas de mortalidad hacia las enfermedades no transmisibles y causas externas. Sin embargo, no hay estudios actualizados sobre la tendencia de la mortalidad prematura por causas externas (MPCE) en Chile y sus variables sociodemográficas. El objetivo del estudio fue evaluar la tendencia de la MPCE en Chile entre 1997-2014 y analizar su distribución según variables sociodemográficas. METODOS: Estudio ecológico mixto. Se utilizó la causa de muerte y los datos demográficos de las bases de mortalidad y estimaciones de población oficiales del gobierno de Chile. Se consideró la MPCE y las causas específicas principales (accidentes de tránsito, lesiones autoinflingidas y agresiones) en la población entre 15-64 años. Se estimaron tasas anuales crudas y ajustadas (método directo) entre 1997-2014. Se evaluó la tendencia de las tasas ajustadas utilizando regresión de Prais-Winsten. RESULTADOS: Hubo 102.559 muertes por causas externas durante el período estudiado (22,1% de la mortalidad total). Los casos se concentraron en hombres (85,3%), en el grupo de 25-44 años (44,8%) y en el nivel de instrucción básico-sin instrucción (48,4%). La tendencia de la MPCE disminuyó significativamente en la población general (ß =-1,18x100.000 habs. IC95%:-1,58;-0,78) y en hombres (ß=-2,25x100.000 habs. IC95%:-2,79;-1,7). En mujeres no hubo cambios significativos en la MPCE, no obstante, se observó un aumento en la MP por agresiones (ß=0,03x100.000 habs. IC95%:0,002;0,05). CONCLUSIONES: Durante el período de estudio se pudo observar una disminución de la MPCE, especialmente la causada por accidentes de tránsito. Sin embargo, no se ha logrado reducir en mujeres, alertando el aumento en la MP por agresiones en este grupo.

Evolución temporal de la mortalidad prematura por causas externas en Chile entre 1997 - 2014 / Temporal trend of premature mortality for external causes in Chile between 1997 -2014

OBJETIVO: Actualmente existe un desplazamiento de las causas de mortalidad hacia las enfermedades no transmisibles y causas externas. Sin embargo, no hay estudios actualizados sobre la tendencia de la mortalidad prematura por causas externas (MPCE) en Chile y sus variables sociodemográficas. El objetivo del estudio fue evaluar la tendencia de la MPCE en Chile entre 1997-2014 y analizar su distribución según variables sociodemográficas. MÉTODOS: Estudio ecológico mixto. Se utilizó la causa de muerte y los datos demográficos de las bases de mortalidad y estimaciones de población oficiales del gobierno de Chile. Se consideró la MPCE y las causas específicas principales (accidentes de tránsito, lesiones autoinflingidas y agresiones) en la población entre 15-64 años. Se estimaron tasas anuales crudas y ajustadas (método directo) entre 1997-2014. Se evaluó la tendencia de las tasas ajustadas utilizando regresión de Prais-Winsten. RESULTADOS: Hubo 102.559 muertes por causas externas durante el período estudiado (22,1% de la mortalidad total). Los casos se concentraron en hombres (85,3%), en el grupo de 25-44 años (44,8%) y en el nivel de instrucción básico-sin instrucción (48,4%). La tendencia de la MPCE disminuyó significativamente en la población general (ß =-1,18x100.000 habs. IC95%:-1,58;-0,78) y en hombres (ß=-2,25x100.000 habs. IC95%:-2,79;-1,7). En mujeres no hubo cambios significativos en la MPCE, no obstante, se observó un aumento en la MP por agresiones (ß=0,03x100.000 habs. IC95%:0,002;0,05). CONCLUSIONES: Durante el período de estudio se pudo observar una disminución de la MPCE, especialmente la causada por accidentes de tránsito. Sin embargo, no se ha logrado reducir en mujeres, alertando el aumento en la MP por agresiones en este grupo

OBJECTIVE: Currently, there is a change in the causes of mortality towards noncommunicable diseases and external causes. However, there are no updated studies on the trend of premature mortality due to external causes (PMEC) in Chile and the underlying sociodemographic variables. The objective of this study was to evaluate the trend of PMEC in Chile between 1997-2014 and analyze its distribution according to sociodemographic variables. METHODS: Ecological mixed study. The cause of death and demographic data of mortality databases and official population estimates of the government of Chile were used. The PMEC and main subcauses (traffic accidents, self-inflicted injuries and aggressions) were considered in the population between 15-64 years. Annual crudes and adjusted rates (direct method) were estimated between 1997-2014. The trend of adjusted rates was evaluated using Prais-Winsten regression. RESULTS: There were 102.559 deaths from external causes during the period studied (22.1% of total mortality). The cases were concentrated in men (85.3%), in the group of 25-44 years (44.8%) and at the basic instruction level-without instruction (48,4%). The PMEC trend decreased significantly in general population (ß=-1.18x100,000 inhab., 95%CI: -1.58,-0.78) and men (ß=-2.25x100,000 inhab. 95%CI: -2.79;-1.7). In women, there were no significant changes in PMEC, however an increase in PM due to aggressions was observed (ß=0.03x100,000 inhab. 95%CI: 0.002,0.05). CONCLUSIONS: During the study period, a decrease in MPCE could be observed, especially that caused by traffic accidents. However, it has not been possible to reduce in women, alerting the increase in MP due to aggressions