[Study of variables associated with skin cancer in Chile using principal component analysis]. / Estudio de variables asociadas al cáncer de piel en Chile mediante análisis de componentes principales.

BACKGROUND: The incidence of skin cancer in Chile has increased in recent years. OBJECTIVE: To associate variables with skin cancer in Chile through indices generated using multivariate descriptive statistical techniques. MATERIAL AND METHOD: During May 2004, information was gathered from demographic, meteorological and clinical data from Chile corresponding to fiscal year 2001, the latest complete, official information available for the country's Health Services as a whole. The variables developed by the following were studied: the National Statistics Institute (INE), the Ministry of Health (MINSAL), the Ministry of Planning and Cooperation (MIDEPLAN), the National Health Fund (FONASA), the Chilean Meteorological Directorate, Federico Santa María Technical University and the Directorate-General for Water. A Principal Component Analysis (PCA) was then performed on the data obtained. RESULTS: The first three principal components were selected, with a cumulative explained variance percentage of 54.48 %. The first principal component explains 24.92 % of the variance, and is related to climatic and geographic variables. The second principal component explains 15.77 % of the variance, and is mainly related to FONASA's beneficiary population and the poverty rate. The mortality rate from skin cancer runs significantly against this component. The third principal component explains 13.79 % of the variance, and is related to population characteristics, such as total catchment population, female population and urban population. CONCLUSION: Performing PCA is useful in studying the factors associated with skin cancer.

Estudio de variables asociadas al cáncer de piel en Chile mediante análisis de componentes principales / Study of variables associated with skin cancer in Chile using principal component analysis

Fundamento. La incidencia de cáncer de piel en Chile ha aumentado en los últimos años. Objetivo. Asociar variables al cáncer de piel en Chile a través de índices generados mediante técnicas estadísticas descriptivas multivariantes. Material y método. Durante el mes de mayo de 2004 se recopiló información de datos demográficos, meteorológicos y clínicos de Chile, correspondientes al ejercicio 2001, última información completa y oficial disponible para la totalidad de los Servicios de Salud del país. Se estudiaron las variables confeccionadas por el Instituto Nacional de Estadística (INE), el Ministerio de Salud (MINSAL), el Ministerio de Planificación y Cooperación (MIDEPLAN), el Fondo Nacional de Salud (FONASA), la Dirección Meteorológica de Chile, la Universidad Técnica Federico Santa María y la Dirección General de Aguas. Se aplicó a los datos obtenidos un análisis de componentes principales (ACP). Resultados. Se seleccionaron las tres primeras componentes principales, con un porcentaje acumulado de variabilidad explicada de 54,48 %. La primera componente principal explica el 24,92 % de la variabilidad y tiene relación con variables del orden climático y geográfico. La segunda componente principal explica el 15,77 % de la variabilidad y se relaciona principalmente con la población beneficiaria de FONASA y el índice de pobreza. En ella se opone de manera importante la tasa de letalidad por cáncer cutáneo. La tercera componente principal explica el 13,79 % de la variabilidad y se relaciona con características poblacionales como población total asignada, población femenina y población urbana. Conclusión. La aplicación del ACP es útil para el estudio de los factores asociados con el cáncer de piel

Background. The incidence of skin cancer in Chile has increased in recent years. Objective. To associate variables with skin cancer in Chile through indices generated using multivariate descriptive statistical techniques. Material and method. During May 2004, information was gathered from demographic, meteorological and clinical data from Chile corresponding to fiscal year 2001, the latest complete, official information available for the country's Health Services as a whole. The variables developed by the following were studied: the National Statistics Institute (INE), the Ministry of Health (MINSAL), the Ministry of Planning and Cooperation (MIDEPLAN), the National Health Fund (FONASA), the Chilean Meteorological Directorate, Federico Santa María Technical University and the Directorate-General for Water. A Principal Component Analysis (PCA) was then performed on the data obtained. Results. The first three principal components were selected, with a cumulative explained variance percentage of 54.48 %. The first principal component explains 24.92 % of the variance, and is related to climatic and geographic variables. The second principal component explains 15.77 % of the variance, and is mainly related to FONASA's beneficiary population and the poverty rate. The mortality rate from skin cancer runs significantly against this component. The third principal component explains 13.79 % of the variance, and is related to population characteristics, such as total catchment population, female population and urban population. Conclusion. Performing PCA is useful in studying the factors associated with skin cancer

Effects of prior anaesthesia on autotomy following sciatic transection in rats.

The animal model for chronic pain following sciatic nerve section in the rat has been studied varying the sensory afferents prior to nerve section, using the anaesthetic blocking of the sciatic nerve. The experimental parameters used were the day of onset of autotomy and the time course of autotomy. The results show that the anaesthetic blocking prior to nerve section significantly reduces the degree of autotomy.