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Resumen Introduccion/antecedentes: La conducta suicida en el trastorno delirante (TD) ha sido escasamente estudiada. Objetivo: Profundizar en el conocimiento de las caracteristicas demograficas, ambientales, psicosociales y clinicas del suicido en un grupo de pacientes con TD con la finalidad de contribuir a generar y sugerir estrategias que contribuyan a realizar nuevos estudios de mayor nivel explicativo. Metodo: Estudio epidemiologico descriptivo retrospectivo de Registro de Casos en el Dispensario de Psiquiatria e Higiene Mental de Cordoba sobre pacientes con TD segun criterios DSM-IV-TR. Aquellos pacientes que cumplieron con los criterios de inclusion definidos constituyeron nuestra muestra final de 261 casos, de ellos 26 casos presentaron evidencias de intento de suicidio. Las variables sobre las que se recogio informacion en base a protocolos, fueron agrupadas con el orden siguiente: I. Sociodemograficos y generales. II. Factores de riesgo del TD (familiares y personales). III. Cuadro Clinico y el Diagnostico del TD (Presentacion, Sintomatologia, Funcionalidad y Discapacidad, utilizacion de los recursos sanitarios, tratamiento, problemas psicosociales, evolucion y curso) y medios letales utilizados. Resultados: La edad media de los pacientes fue de 47 anos y el 60% fueron hombres. Los datos sociodemograficos muestran que los pacientes con intento de suicidio residian en nucleos rurales (46,2%), no tenian estudios en un 15,4%, un 57,7% no trabajaba y un 26,9% recibia una pension por enfermedad o jubilacion laboral. El subtipo persecutorio con 8 casos, fue el mas frecuente, seguido de los subtipos de grandiosidad (6 casos) y celotipico (6 casos), mixto (3 casos), erotomaniaco (2 casos) y somatico (1 casos). Discusion y conclusion: Son necesarios futuros estudios prospectivos para investigar los factores de proteccion, de riesgo y/o asociados al suicidio en el TD.

Resumen Introduccion La infeccion de localizacion quirurgica (ILQ), superficial y profunda, es un problema muy frecuente dentro de la infeccion hospitalaria. Supone un riesgo para la seguridad del paciente y, por tanto, su reduccion es una prioridad para los sistemas sanitarios. El objetivo del estudio fue analizar la incidencia de ILQ en los servicios quirurgicos de un hospital de tercer nivel. Material y metodos Estudio de cohortes prospectivo sobre 14.455 pacientes ingresados desde enero de 2001 hasta diciembre de 2004. Se calcularon la incidencia acumulada (IA), cruda y ajustada por el indice del National Nosocomial Infection Surveillance (NNIS) y densidad de incidencia (DI) de ILQ. Resultados La IA de pacientes con ILQ fue 3,4% (IC95%: 3,0–3,7%), la IA de ILQ 3,5% (IC95%: 3,2–3,8%) y la DI 0,28/100 pacientes intervenidos-dia. Las unidades con IA mas elevadas fueron cirugia maxilofacial (6%), digestiva (5,3%) y cardiovascular (5,1%). Ajustando por la estancia, urologia y cirugia pediatrica registraron las mayores tasas de incidencia, mientras que oftalmologia y neurocirugia obtuvieron las menores. La cirugia de colon y recto tuvieron los parametros mas elevados (IA=10%; DI=0,57), seguido de la revascularizacion miocardica y la protesis de cadera. En el conjunto de las unidades y en los procedimientos investigados, la IA de ILQ aumento con el indice NNIS. Conclusiones La IA y la DI de ILQ fueron similares a las obtenidas en los proyectos de vigilancia europeos e inferiores a las registradas en 1994 en este mismo hospital, reflejo de una mayor intensidad en la vigilancia y de una mayor concienciacion en la aplicacion de sus medidas de control.

To evaluate the risk of PD associated with tea consumption.We reviewed all observational studies that evaluated the association between PD risk and tea consumption. Only, 12 studies were identified: 11 case-control and 1 cohort. These studies were carried out between 1981 and 2003. The studies represented different populations from 3 continents; North America, Europe and Asia. The 3 studies from Asia were case-control studies of Chinese populations.There was a clear protective effect of tea consumption in the pooled risk estimate [OR: 0.83 (95% confidence interval 0.74 to 0.92)] with 2215 cases and 145578 controls. However, the homogeneity test was significant (p value of 0.008), denoting heterogeneity across the pooled studies. Pooled analysis applying the random effect model was OR: 0.81 with 95% confidence interval nearly overlapping unity (95% confidence interval 0.67 to 0.98). Tea consumers versus non-consumers in Chinese populations had pooled OR of 0.73 with 95% confidence interval 0.60 to 0.90 (470 cases and 623 controls). The p value of homogeneity test was 0.96, denoting homogeneity across the pooled 3 studies.Tea consumption can protect against PD and this protective effect is clearer in Chinese populations. The low rate of tea consumption among persons with PD should provide us many valuable insights into the nature of the illness.

BACKGROUND Hospital-acquired pneumonia (HP) is the most common infection in adult intensive care units (ICUs). To develop effective strategies to prevent it, we identified factors that independently increased the risk of contracting HP while admitted at an ICU. METHODS We performed a prospective cohort study during 4 years in which we included all patients who had been admitted for at least 24 h to the ICU at a university reference hospital in Spain. We conducted a multivariable Cox regression analysis to obtain adjusted hazard ratios (HR). The dependent variable for patients with HP was duration of ICU stay prior to the onset of HP. For those without HP, the dependent variable was duration of stay between admission and discharge from the ICU. The independent variables were intrinsic characteristics of the patients already present at admission to the ICU and diagnostic or therapeutic procedures performed during admission. RESULTS We studied 4427 patients, of which 233 (5.3%) developed HP while admitted to the ICU. The strongest independent risk factors associated with the occurrence of HP were mechanical ventilation (HR = 8.2; 95% CI = 3.6-18.9) and the use of a nasogastric tube (HR = 2.3; 95% CI = 1.6-3.3). The intrinsic risk factors that were part of the model were the presence of decreased level of consciousness upon admission (HR = 2.0; 95% CI = 1.5-2.7) and the APACHE II index (HR = 1.018; 95% CI = 1.002-1.035). CONCLUSIONS Although severity of illness upon admission (APACHE II index) and decreased level of consciousness were relevant predisposing factors to contract HP in the ICU, the strongest association corresponded to extrinsic factors such as mechanical ventilation and use of a nasogastric tube. The fact that these are therapeutic interventions facilitates developing prevention and control measures that can contribute to reduce the risk for HP.

To estimate the pooled risk of petroleum industry for urinary bladder cancer.All observational studies that evaluated the association between urinary bladder risk and the petroleum industry were reviewed. We have only identified eight case-control studies. These studies were carried out between 1989 and 1995.Of the eight localized studies six were exclusively for males. The other two studies included both males and females, but none reported separately the risk among men and women. There was an obvious risk of petroleum industry in the pooled risk (odds ratio 1.4, 95% confidence interval (CI) 1.27-1.54). Also, Q test was not significant (P0.1), denoting homogeneity across the pooled studies. Pooled analysis applying the random effect model was 1.50 (95% CI 1.29-1.75).Although our pooled estimate shows that the petroleum industry is associated with the risk of urinary bladder cancer, the eight studies were based on retrospective data from case-control studies. Further prospective studies evaluating the association between petroleum industry and urinary bladder cancer risk are strongly needed.

We estimated the pooled risk of tobacco smoking for Parkinson's disease (PD). Inclusion criteria included systematic searches of MedLine, PsycLIT, Embase, Current Contents, previously published reviews, examination of cited reference sources, and personal contact and discussion with several investigators expert in the field. Published prospective studies on PD and cigarette smoking. When two or more studies were based on an identical study, the study that principally investigated the relationship or the study that was published last was used. Seven prospective studies were carried out between 1959 and 1997, of which six reported risk estimates. Four cohorts were based on standardised mortality rates, which were exclusively of male. Only one study included risk estimates for both males and females separately. The risk of ever smoker was 0.51 (95% confidence interval, 0.43 to 0.61). There was an obvious protective effect of current smoking in the pooled estimate (relative risk, 0.35; 95% CI, 0.26-0.47). Former smokers had lower risk compared with never smokers (relative risk, 0.66; 95% CI, 0.49-0.88). Although our pooled estimates show that smoking is inversely associated with the risk of PD, the four prospective studies that were based on follow-up of mortality of smokers had many limitations. Further studies evaluating the association between smoking and PD in women are strongly needed.

To estimate the pooled risk of tobacco smoking for Parkinson's disease (PD) in patients with and without PD family history. We conducted systematic searches of Medline, PsycLIT, Embase, Current contents, Best Evidence, Nisc Mexico Biblioline, previous reviews, examination of cited reference sources and personal contact and discussion with several investigators expert in the field. Studies in all languages were considered. Published observational studies on PD and cigarette smoking stratified by PD family history were reviewed. When two or more papers were based on an identical study, the paper that principally investigated the relationship between PD, smoking stratified by PD family history or the paper that was published last was used. Three case-control studies were carried out between 1996 and 2000, of which one reported risk estimates. The risk of ever smoker in patients with positive PD family history was 0.82 (95% confidence interval 0.44-1.53). There was an obvious protective effect in the pooled estimate in patients with negative PD family history [odds ratio 0.77 (95% confidence interval 0.59-1.01)]. Although our pooled estimates show that smoking is inversely associated with the risk of PD only in patients with negative PD family history, further studies evaluating the interaction between smoking and PD family history are strongly needed.

Aim: An epidemiological cross-sectional study was conducted to evaluate the association between cutaneous melanoma, Hodgkin's lymphoma and non-Hodgkin's lymphoma in 40 European countries. Methods: Incidence rates were obtained from the database of the International Agency for Research of Cancer (IARC). We analyzed age-adjusted and gender-stratified incidence rates for cutaneous melanoma, Hodgkin's lymphoma and non-Hodgkin's lymphoma in 40 European countries. All European countries included had registration systems that fulfilled the quality criteria of IARC. Normal distribution of the variables was examined using Kolmorov-Smirnov test before calculating their correlations using Pearson's Correlation test. Results: In males, positive correlations were found between cutaneous melanoma, Hodgkin's lymphoma (r=0.14, p=0.38), and non-Hodgkin's lymphoma (r=0.64, p

La anisakiasis o anisakidosis es una zoonosis parasitaria provocada por la infestacion de nematodosde la familia Anisakidae, principalmente la especie Anisakis simplex (AS). Su distribuciones mundial, aunque su aparicion es reciente en Espana (1991) habiendose descrito19 casos previos a este estudio. Presentamos 13 casos diagnosticados en distintos centros hospitalariosde la provincia de Cordoba desde septiembre de 1994 hasta julio de 1998, lo que representala mayor serie de casos descrita en Espana por el momento. Todos los pacientes comenzaronclinicamente como un cuadro de abdomen agudo por lo que se trataron mediante acirugia precoz en la que se observo un segmento intestinal inflamado y estenotico que fue resecado.El estudio histologico de la pieza revelo un importante infiltrado eosinofilo en la mucosa.En un caso se detectaron fragmentos del parasito en la mucosa intestinal y en los 12 restantesel diagnostico fue inmunologico mediante la determinacion de IgE especifica anti-Anisakis simplexy la deteccion de antigenos del nematodo mediante anticuerpos monoclonales. Como antecedenteepidemiologico de interes cabe resaltar que todos los pacientes referian ser comedoreshabituales de pescado crudo (principalmente boquerones en vinagre) que actua como huespedde larvas terciarias del parasito.

Objective:To identify risk factors predictive of nosocomial infection in an intensive-care unit (ICU) and to identify patients with a higher risk of nosocomial infection using a predictive model of nosocomial infection in our ICU.Design:Prospective study; daily concurrent surveillance of intensive-care-unit patients.Setting/Patients:All patients admitted for at least 24 hours to the ICU of a tertiary-level hospital from February to November 1994 were followed daily.Methods:Variables measuring extrinsic and intrinsic risk factors for nosocomial infection were collected on each patient during their ICU stay, and the Cox Proportional Hazards multivariable technique was used to identify the variables significantly associated with infection.Results:The population studied consisted of 944 patients. The main risk factors identified were intrinsic; the significant extrinsic risk ofactors identified were head of the bed in a horizontal (Conclusion:The important preventive measures derived from our results are that underlying conditions suffered by the patient at the ICU admission should be corrected promptly, the depression of the patient's level of consciousness with sedatives should be monitored carefully, and the horizontal position of the head of the bed should be avoided totally. Patients with a high risk of infection can be the target of special preventive measures.

This study describes the behavior of eight statistical programs (BMDP, EGRET, JMP, SAS, SPSS, STATA, STATISTIX and SYSTAT) when performing a logistic regression with a simulated data set that contains a numerical problem created by the presence of a cell value equal to zero. The programs respond in different ways to this problem. Most of them give a warning, although many simultaneously present incorrect results, among which are confidence intervals that tend toward infinity. Such results can mislead the user. Various guidelines are offered for detecting these problems in actual analyses, and users are reminded of the importance of critical interpretation of the results of statistical programs.

ResumenLos pinchazos con aguja son los accidentes laborales más frecuentes en el ámbito hospitalario. El presente estudio tiene como objetivo identificar factores asociados a la accidentabilidad por pinchazo con aguja en el hospital, así como cuantificar el riesgo que los mismos suponen.Para ello se llevó a cabo un estudio de casos y controles, cuyo sujeto de estudio fue el personal de enfermería del hospital “Reina Sofía” de Córdoba, con un período de estudio que abarcó desde el 30-6-90 al 30-6-91.El factor más significativamente asociado a pincharse accidentalmente fue encapuchar agujas tras su uso, estimándose el riesgo en 3,95, 7,68 y 17,85 veces más alto entre los que encapuchaban a veces, con frecuencia y siempre, respectivamente, con respecto a los que no encapuchaban nunca. La experiencia profesional resultó ser un factor protector frente a los pinchazos (OR= 0,93, IC 95% = 0,89, 097), estimándose que se pincha menos de la mitad del personal cuando tienen una década de experiencia.El conocimiento de éste y otros factores es importante para la organización de programas de prevención específicos si bien es necesario identificar más factores de riesgo.SummaryThe needlestikck injuries are the most frequent accidents among hospital staff. The aim of this study is to identify some factors associated with accidents caused by needlestick injuries at hospitals, so as to measure the risk that they present.A case-control study has been made, the subject of which is the nurses working at “Reina Sofía” Hospital in Córdoba and within the period June, 301990 and June, 30 1991.A more significant factor in relation to needlestick injuries was the recapping of the needle after being used. The risk of injury being 3.95, 7.68 an 17.85 times higher between those who reccapped sometimes, frequently and always, respectively, versus those who had never recapped needles. Professional experiences resulted in being a protectorfactoragainstthe needlestick injuries (OR= 0.93; 95% Cl = 0.89; 0.97; it's estimated that the risk injuring is less than half among personnel having ten years of experience.Knowing these risk factors is important for the development of specific prevention programs Nevertheless, it is still important to identify other risk factors.

Introduction Surgical site infection (SSI) is a very common problem in hospital infection control. It represents a risk for the safety of the patient and therefore its reduction is a priority in Health Services. The aim of the study is to analyse the incidence of SSI in the surgical departments of a tertiary hospital. Material and methods A prospective cohort study was conducted on 14,455 patients admitted from January 2001 to December 2004. The cumulative incidence (CI) crude and adjusted for the National Nosocomial Infection Surveillance (NNIS) index and the incidence density (ID) of SSI were calculated. Results The CI of patients with SSI was 3.4% (95% CI: 3.0%–3.7%), the CI of SSI was 3.5% and the observed ID was 0.28/100 surgical patients/day. Surgical units with the highest CI were maxillofacial (6%), gastrointestinal (5.3%) and cardiovascular (5.1%). Adjusting for length of stay, urology and paediatric surgery recorded the highest incidence rates, while ophthalmology and neurosurgery had the least. Colorectal surgery had the highest parameters (CI=10%; ID=0.57), followed by myocardial revascularisation and hip prosthesis. Among the surgical units and operative procedures assessed, the CI of SSI increased with the NNIS index. Conclusions The CI and ID of SSI observed in this study were similar to those obtained in previous European surveillance projects, and lower than those recorded in our hospital in 1994 which reflects a higher level of vigilance and a higher awareness in applying control measures.

To estimate the pooled risk of coffee consumption for Alzheimer's disease (AD).We have reviewed all observational studies that evaluated the association between AD risk and coffee consumption. Four studies were identified: two case-control studies and two cohorts. These studies were carried out between 1990 and 2002.There was an obvious protective effect of coffee consumption in the pooled estimate [risk estimate: 0.73 (95% confidence interval: 0.58-0.92)]. However, the homogeneity test was highly significant (p0.01), indicating heterogeneity across the pooled studies. Pooled analysis applying the random effect model was 0.79 with 95% confidence interval overlapping unity (95% confidence interval: 0.46-1.36). Three studies assessed coffee consumption by interview questionnaire. The risk of AD in coffee consumers versus non-consumers in studies that used interview questionnaire had a pooled risk estimate of 0.70 with 95% confidence interval 0.55-0.90.Although our pooled estimates show that coffee consumption is inversely associated with the risk of AD, the four studies had heterogeneous methodologies and results. Further prospective studies evaluating the association between coffee consumption and AD are strongly needed.

The rising incidence of urinary bladder cancer is alarming and potential relationships with different risk factors have been postulated. The purpose of this study was to examine the possible relationship between different environmental risk factors and urinary bladder cancer. All men with urinary bladder cancer who were admitted to the Department of Urology of Reina Sofia University Hospital of Cordoba, Spain over 1 year were included in our study. Men were administered an interview questionnaire, which included data on history of known urinary bladder cancer risk factors. Comparisons between men with urinary bladder cancer (cases) and those with nonmalignant urological disease (controls) were made. The study included 74 cases and 89 controls. The variables associated with malignant lesions on univariate analysis were age, smoking and drinking alcohol. Meanwhile, fish, poultry and beef consumption were proved to be protective factors. The risk factors identified by the logistic regression analysis were age, smoking and fluid intake. The independent protective factors on the multivariate analysis were fish and poultry consumptions. Smoking was found to be the principal independent risk factors for urinary bladder cancer. Our results call for further investigation of urinary bladder cancer risk factors; future studies should preferably be performed on large prospective cohorts, to increase their validity.

Perhaps one of the most important questions posed by the neurobiology of aging concerns the pathogenic mechanisms in Parkinson's disease (PD). Recently, it was suggested that exposure to pesticides could be the main cause of PD. Another study reported that the environmental endotoxin, lipopolysaccaride produced by Salmonella minnesota, might be a risk factor for PD. An alternative explanation is the genetic component, which has been suggested to be an important risk factor. Epidemiological studies have identified a positive family history of Parkinson as one of the most important risk factors for the disease. However, these studies neither examined nor reviewed the medical records of the family members. The twin study stated that the major factors in the etiology of PD are non-genetic. Meanwhile, epidemiological studies from China have shown that the prevalence of PD is much lower than in the Caucasian population, explained by the low frequency of cytochrome P-450 CYP2D6 debrisoquine hydroxylase gene polymorphism. The etiology of idiopathic PD is still a question for scientists, and calls for further research, especially with the growing proportion of elderly and the rising incidence of PD worldwide. Future research for PD risk factors should consider that multiple interactions occur in PD, resulting in a complex trait, which includes genetic, acquired, and environmental components.

Invasive pulmonary aspergillosis is a severe infection, with a sharp increase during the last decades. Our study aimed at identification of the epidemiological characteristics of invasive pulmonary aspergillosis during a period of four years. All clinical records with pulmonary isolation of Aspergillus species were reviewed, as a part of surveillance program at Reina Sofia University Hospital, from January 1995 to December 1998. Diagnosis of invasive pulmonary aspergillosis was based on criteria of Centers for Disease Control and Prevention. Of the 50 patients identified 78% were males and 44% were current or ex-smokers. Chronic respiratory diseases were identified in 64% of them, and 60% were receiving immunosuppressives. Twenty percent of our patients had been subjected to lung transplantation and 28% to organ transplantation in general. Only 78% had received specific antifungal treatment and 56% had fatal prognosis. Our findings match with previous studies, apart from the high frequency of lung transplantation in our series. We recommend further studies on large prospective cohorts.

The accumulation of risk factors in hospitalized patients is one of the elements contributing to the increase in the frequency of nosocomial infection in the intensive care unit (ICU). Our aim was to identify nosocomial infection risk factors in the ICU of our hospital.We performed a prospective cohort study of 1,134 patients admitted to the ICU for at least 24 hours in 2001. The patients were followed-up for 48 hours after leaving the ICU. Multivariate Cox regression analysis was used to identify risk factors.The intrinsic risk factors identified were the principal diagnosis motivating admission to the ICU, traumatic brain injury and renal insufficiency. Invasive techniques that were independently associated with nosocomial infection (from high to low risk) were urinary catheter, tracheostomy, mechanical ventilation, Swan-Ganz catheter, and total parenteral nutrition.Although endogenous risk factors, which cannot be modified, represented the most important associated factors, steps to reduce nosocomial infections should concentrate on the following exogenous risk factors: urinary catheter, tracheostomy, mechanical ventilation, Swan-Ganz catheters, and total parenteral nutrition.

Aspergillosis is the second most frequent fungal infection after candidiasis in teaching hospitals. Clinical manifestations of pulmonary aspergillosis range from asymptomatic colonization to disseminated disease. The aim of this study was to identify the risk factors associated with invasive pulmonary aspergillosis, in patients with positive pulmonary isolation of Aspergillus species. A review was undertaken of all clinical records with pulmonary isolation of Aspergillus species at Reina Sofia University Hospital from January 1995 to December 1998. Data collected were: age, gender, history of smoking, past medical history, such as chronic pulmonary disease, immunosuppression, granulocytopenia in the past 6 months and during the last admission, history of surgery including within the last year of the study period, number of hospital admissions and clinical evidence of invasive pulmonary aspergillosis. To investigate all the possible risk factors for invasive pulmonary aspergillosis, a multivariable logistic regression model was used. 132 patients with positive pulmonary isolation were identified, of which 42.4% had clinical evidence of invasive pulmonary aspergillosis. The independent factors significantly associated with invasive pulmonary aspergillosis were: granulocytopenia in the past 6 months, immunosuppression in the last admission and the number of hospital admissions within the past year. Patients with a history of granulocytopenia in the past 6 months and immunosuppression in the last admission are the high-risk group for invasive pulmonary aspergillosis. However, invasive pulmonary aspergillosis can also occur in mild granulocytopenic or even immunocompetent patients.

A systematic review was conducted to estimate the pooled risk of smoking for Parkinson's disease in Chinese populations. The four identified case-control studies had odds ratios with 95% confidence intervals nearly or overlapping unity. Pooled odds ratio of these studies was 0.77 with 95% confidence interval 0.60 to 0.97. It was suggested that smoking induces debrisoquine 4-hydroxylase, which is responsible for the metabolism of antipsychotic drugs and the detoxification of certain environmental toxins known to cause dopaminergic neural damage. This could be the explanation of these contradictory results as cytochrome P-450 CYP2D6 debrisoquine hydroxylase gene polymorphism is known to be much lower in Chinese than in Caucasian people. This systematic review raises concerns about generalization of the conclusion previously settled by many cohort and case-control studies.

The chronic effects of polychlorinated biphenyls (PCBs) are a public health concern, and a potential relationship with breast cancer has been postulated. The purpose of this study was to examine the possible relationship between PCBs and breast cancer. All women (134) treated by excision biopsy because of breast lump at Reina Sofia University Hospital, Cordoba, Spain over a period of 10 months were included in our study. They were all administered a questionnaire by interview, calculation of body mass index, histopathological examination of excised mass and chemical estimation of PCB congener levels in breast fat. The collected samples were from 65 (48.5%) women with benign lesions and 69 (51.5%) with malignant lesions. The variables associated with malignant lesions on univariate analysis were age, lactation period, overweight, PCB n-28 and PCB n-52. On the multivariate analysis PCB n-28 was found to be the most important risk factor (OR 9.6, 95% CI 3.8-24.4). Other risk factors were identified as age, drinking alcohol, low parity and overweight. If these findings can be confirmed in a large study population, however, they may have important implications for breast cancer risk.

Objective: Comparison of statistical methods and measurement scales to identify nosocomial infection risk factors in intensive care units (ICU). Design: Prospective study in 558 patients admitted to the ICU of a referral hospital between February and November 1994. Methods: Analysis using three logistic regression models, three standard Cox regression models, and two Cox regression models with time-dependent extrinsic factors. Different scales were used to measure exposures to risk factors (dichotomous, ordinal, quantitative, and time-dependent variables). Results: The most appropriate models were those that measured exposure using dichotomous variables. Models using ordinal or quantitative variables estimated biased coefficients and/or failed to comply with the statistical assumptions underlying the analyses. The Cox regression model with quantitative time-dependent variables met all the statistical assumptions, obtained a precise assessment of risk by exposure time, and estimated unbiased coefficients. Conclusions: The Cox regression analysis with quantitative time-dependent variables is the most valid alternative for assessing the risk of nosocomial infection per day of exposure to an extrinsic risk factor in the ICU.

Introduccion. La revision y el analisis continuos del conocimiento existente han sido siempre necesarios para el avance de la ciencia y la practica clinica. Este trabajo presenta la diferencia entre una revision narrativa y una sistematica, los puntos mas destacados del metaanalisis y termina con una detallada descripcion de sus etapas. Nuestro objetivo es explicar, de forma sencilla, la tecnica del metaanalisis, lo que puede permitir su aplicacion y uso en la practica clinica y las investigaciones neurologicas. Desarrollo. El metaanalisis como termino lo empleo por primera vez el psicologo Glass en 1976. Desde entonces, el metaanalisis ha sido utilizado por muchos investigadores como tecnica para combinar resultados de diferentes estudios. Las etapas de un metaanalisis son: 1. Una hipotesis de trabajo; 2. Localizacion de los estudios de investigacion; 3. Seleccion de los estudios localizados; 4. Metaanalisis cualitativo; 5. Metaanalisis cuantitativo (se refiere basicamente al aspecto numerico de combinacion de los datos que antes han extraido los revisores; debe elegirse el metodo matematico que se utilizara para evaluar el tamano del efecto, y han de realizarse pruebas de homogeneidad y sensibilidad), y 6. Resultados y conclusiones. Conclusiones. Los metaanalisis bien realizados se aceptan como una manera optima de expresar los resultados de los diferentes estudios bajo un punto de vista comun. Este tecnica del metaanalisis puede ser util para la practica clinica y las investigaciones neurologicas.

Objetivo. Esta revision presenta y discute los principales factores de riesgo (FR) de la enfermedad de Parkinson (EP) aportados por los estudios epidemiologicos y bioquimicos. Desarrollo. Los FR mas escritos son: 1) Edad: la EP no se trata de una patologia exclusiva de las personas mayores, aunque la mayoria de los enfermos superan los 60 anos; 2) Sexo: en la mayoria de los estudios epidemiologicos no se observan diferencias en la prevalencia de EP segun el sexo; 3) Genetica: no se ha identificado ningun gen como el responsable en EP idiopatica; sin embargo, se han identificado los antecedentes familiares de EP como FR; 4) Traumatismos craneoencefalicos: este factor puede tener un sesgo sistematico, dado que los pacientes buscan una explicacion para su enfermedad y recuerdan cualquier traumatismo como posible causa de la misma; 5) Neurotoxinas: muchas investigaciones se enfocaron hacia la relacion entre EP y la exposicion directa o indirecta a los compuestos como MPTP, contenido en los pesticidas; 6) Antioxidantes: se sospecha que su suficiente ingesta, como parte de la dieta o suplementarios, podria bajar el riesgo de EP o decelerar su progreso; 7) Consumo de tabaco: varios estudios mostraron una relacion negativa, mientras que otros estudios no encontraron ninguna relacion significativa. Conclusiones. Son varios los posibles FR en EP; sin embargo, no se ha encontrado, hasta ahora, ningun factor determinante para su desencadenamiento. Los futuros estudios deben plantear la hipotesis de una etiologia multifactorial y tener en cuenta la interaccion entre los factores geneticos y ambientales

Introduccion. Varias revisiones sistematicas anteriores han informado sobre el efecto protector del tabaco contra la enfermedad de Parkinson (EP). Sin embargo, ninguna revision intento examinar este efecto en enfermos de Parkinson con inicio temprano. Objetivo. Examinar la asociacion entre la EP temprana (EPT) y el tabaquismo. Material y metodo. Se emplearon las tecnicas de metanalisis con la inclusion de todos los estudios de observacion publicados sobre esta asociacion hasta enero de 2003. No se aplico ninguna restriccion de idioma o ano de publicacion. Se extrajo o calculo el riesgo estimado, con su intervalo de confianza del 95% (IC 95%), de los estudios encontrados con enfermos de Parkinson temprano. Resultados. Se localizaron cinco estudios de casos y controles que trataban de forma especifica el riesgo de EPT, que comparaban individuos con Parkinson y sin Parkinson, respecto al consumo de tabaco, y se comparaban con fumadores y no fumadores. La estimacion global mediante el modelo de efectos fijos fue de 0,55, con un IC 95% del 0,38-0,81. La prueba de homogeneidad no fue significativa. Conclusiones. Este metanalisis demuestra el efecto protector del tabaco contra la EPT y, asimismo, coincide con los resultados obtenidos en otras revisiones que no consideraron la edad de inicio del Parkinson. No obstante, se recomiendan estudios prospectivos sobre la forma temprana del Parkinson.

Summary. Introduction . Many studies have shown that smoking is lower in patients with Parkinson’s disease. However, in otherinvestigations this was not observed. The various studies involved showed wide variation with regard to methodology, criteria fordiagnosis and periods of observation and hence it is difficult to compare them. Development . The first studies published weredesigned to examine the effects of smoking in general and information was obtained regarding the possible disorders related totobacco smoking according to the records of mortality, which may contain errors due to selective mortality and mistaken diagnosis.Most of the studies of cases and controls included prevalent cases which accepted the study, mainly hospital cases. Also it is probablethat the prevalent cases of Parkinson ’s disease do not smoke because of their disorders of movement. Conclusions . Many researchershave found important information about the pathophysiology of Parkinson ’s disease and its association with smoking. However, thehypothesis regarding the association between smoking and low risk of Parkinson ’s disease are various and independent, apart fromthe hypothesis of a truly biological mechanisms. Since the subject is still controversial, systematic reviews together with epidemio-logical and experimental studies are necessary. [REV NEUROL 2002; 34: 686-9]