[The effects of air pollution on health: an introduction]. / Efectos de la contaminación atmosférica sobre la salud: una introducción.

In recent years, major progress has been made as regards the knowledge and understanding which has been gained of the impact of air pollution. In this study, the basic concepts are set out regarding this subject, and the different possible approaches as far as methodologies are concerned are reviewed. Among the epidemiological studies, the time series studies are those most often used for assessing the short-term impact of air pollution. The most important factors leading to confusion in this type of study are the seasonal and weekly changes, the tendency, the weather variables and the serious illnesses of a seasonal pattern, such as the flu. The main short-term impact of air pollution on human health range from a rise in the overall death rate resulting from respiratory and cardiovascular diseases to the worsening of lung function and other symptoms, including a rise in the number of doctor visits and hospital admissions. Despite a widespread consensus existing with regard to the harmful impact of air pollution, there are a number of questions currently in the need of further research.

[A review of original papers that analyze the effects of air pollution on mortality, 1994-1998]. / Revisión de los trabajos originales que analizan los effectos de la contaminación atmosférica en la mortalidad, 1994-1998.

The different studies published and indexed in Medline and in the Spanish Medical Index (IME) from 1984 up to 1998 (IME: 1971-1996) are reviewed. To start with, an assessment was made of the number of publications put out which have to do with the impact of pollution on human health as well as the percentage thereof which analyze the mortality as a health indicator. Afterward, the original works published within the January 1994-June 1998 period were reviewed in detail. Most of the original articles are combined time series studies which analyze, on a single-day basis, the relationship between the levels of pollution and the mortality for non-accidental causes. Other original articles were also summarized based on an approach other than the time series one, highlighting different cohort studies which relate the levels of pollution to the mortality on an individual level and which confirm the findings of prior ecological studies. The pollutants analyzed most often are the different types of particles, although studies are also common regarding the impact of sulfur dioxide, nitrogen dioxide, ozone and carbon monoxide. The method of analysis most used is the Poisson regression, into which different confusion variables bearing an impact thereon such as seasonality and tendency, temperature and relative humidity and day of the year are basically added. In the studies reviewed, the positive significant findings prevail, being consistent especially for particles, which is the pollutant most analyzed. The articles studying other pollutants, although fewer in number, also indicate a significant relationship between pollution levels and the mortality.

[The EMECAM project: the Spanish Multicenter Study on the Relationship between Air Pollution and Mortality. The background, participants, objectives and methodology]. / El proyecto EMECAM: Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad. Antecedentes, participantes, objetivos y métodología.

In recent years, a growing number of studies suggests that increases in air pollution levels may have short-term impact on human health, even at pollution levels similar to or lower than those which have been considered to be safe to date. The different methodological approaches and the varying analysis techniques employed have made it difficult to make a direct comparison among all of the findings, preventing any clear conclusions from being drawn. This has led to multicenter projects such as the APHEA (Short-Term Impact of Air Pollution on Health. A European Approach) within a European Scope. The EMECAM Project falls within the context of the aforesaid multicenter studies and has a wide-ranging projection nationwide within Spain. Fourteen (14) cities throughout Spain were included in this Project (Barcelona, Metropolitan Area of Bilbao, Cartagena, Castellón, Gijón, Huelva, Madrid, Pamplona, Seville, Oviedo, Valencia, Vigo, Vitoria and Saragossa) representing different sociodemographic, climate and environmental situations, adding up to a total of nearly nine million inhabitants. The objective of the EMECAM project is that to asses the short-term impact of air pollution throughout all of the participating cities on the mortality for all causes, on the population and on individuals over age 70, for respiratory and cardiovascular design causes. For this purpose, with an ecological, the time series data analyzed taking the daily deaths, pollutants, temperature data and other factors taken from records kept by public institutions. The period of time throughout which this study was conducted, although not exactly the same for all of the cities involved, runs in all cases from 1990 to 1996. The degree of relationship measured by means of an autoregressive Poisson regression. In the future, the results of each city will be combined by means of a meta-analysis.

[The EMECAM protocol: an analysis of the short-term effect of air pollution on mortality. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica u la Mortalidad]. / Protocolo EMECAM: análisis del effecto a corto plazo de la contaminacion atmosférica sobre la mortalidad.

The aim of this study is to Mortality show the protocol of analysis which was set out as part of the EMECAM Project, illustrating the application thereof to the effect of pollution has on the mortality in the city of Valencia. The response variables considered will be the daily deaths rate resulting from all causes, except external ones. The explicative variables are the daily series of different pollutants (black smoke, SO2, NO2, CO, O3). As possible confusion variables, weather factors, structural factors and weekly cases of flu are taken into account. A Poisson regression model is built up for each one of the four deaths series in two stages. In the first stage, a baseline model is fitted using the possible confusion variables. In the second stage, the pollution variables or the time legs thereof are included, controlling the residual autocorrelation by including mortality time lags. The process of fitting the baseline model is as follows: 1) Include the significant sinusoidal terms up to the sixth order. 2) Include the significant temperature or temperature squared terms with the time lags thereof up to the 7th order. 3) Repeat this process with the relative humidity. 4) Add in the significant terms of calendar years, daily tendency and tendency squared. 5) The days of the week as dummy variables are always included in the model. 6) Include the holidays and the significant time lags of up to two weeks of flu. Following the reassessment of the model, each one of the pollutants and the time lags thereof up to the fifth order are proven out. The impact is analyzed by six-month periods, including interaction terms.

[The short-term effects of air pollution on mortality. The results of the EMECAM project in the city of Valencia, 1994-96. Estudio Multcéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad]. / Efectos a corto plazo de la contaminación atmosférica sobre la mortalidad. Resultados del proyecto EMECAM en la ciudad de Valencia, 1994-96.

BACKGROUND: To determine the short-term impact of air pollution on mortality in the city of Valencia throughout the 1994-1996 period by employing the analysis method of the Spanish multicenter study with regard to the relationship between air pollution and the mortality (EMECAM Project). METHODS: The daily levels of black smoke, sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3) were obtained from the Valencia air pollution monitoring network. The death rate indicators analyzed were the daily number of death due to all causes, except the external ones, the deaths of those over age 70, and the deaths resulting from respiratory and cardiovascular diseases. Following the methods of the EMECAM Project, autoregressive Poison regression models were built up, controlling the different confounding factors (seasonality, trend, calendar, weather variables and flu impact). RESULTS: For total mortality except the external ones, a significant impact of black smoke (RR 10 micrograms/m3: 1.013; CI95% 1.003 to 1.023) and for CO 24 la (RR 1 mg/m3: 1.024; CI95% 1.003 to 1.046) was found. For the mortality of those individuals over 70, the estimated impact was somewhat greater than for black smoke (RR 10 micrograms/m3: 1.017; CI95% 1.005-1.029), as well as for CO2 1 h (RR 10 micrograms/m3: 1.007; CI95% 1.001-1.013). No significant relationship was found with the mortality due to respiratory or cardiovascular diseases for the entire period. CONCLUSIONS: The current levels of pollution in the city of Valencia show a significant impact on daily mortality. These findings are consistent with the previous research and are coherent with those obtained on analyzing the relationship between air pollution and morbidity indicators.

[The EMECAM project: a discussion of the results in the participating cities. Estudio Multicéntrico Español sobre la Relación entre la Contaminación Atmosférica y la Mortalidad]. / El proyecto EMECAM: discusión de los resultados en las ciudades participantes.

This article draws a comparison and provides a discussion of the findings resulting from the local analyses of the 14 cities participating in the EMECAM Project. An analysis is made of the time series related to mortality, pollutants (particles in suspension, SO2, NO2, O3 and CO), temperature and other factors taken from records of public institutions. By using Poisson autoregressive regression, an estimate has been made of the short-term relationship between the number of deaths and the air pollution indicators in each one of the following cities: Barcelona, metropolitan area of Bilbao, Cartagena, Castellón, Gijón, Huelva, Madrid, Pamplona, Seville, Oviedo, Valencia, Vigo, Vitoria and Saragossa. The findings reveal the air pollution figures in our country to be similar to those of other European cities. The levels of the different pollutants point toward road traffic as being the main source of most of this pollution. A relationship has been found between the mortality and different pollutants in most cities, although the results are not homogeneous among the cities and show variability in the different causes under study. In some cities, especially in those having smaller populations, there have been no findings providing any evidence of a relationship, or the findings themselves are not highly consistent. The meta-analysis will provide estimates for all of the cities as a whole and will allow the possibility of making a more clear-cut assessment of the time lag impact of air pollution on the mortality. Worthy of special mention is the participation in this project of public health officers as actively involved researchers.

[Identification of emergencies for asthma and chronic obstructive pulmonary disease in the emergency rooms of a hospital. A reliability study]. / Identificación de urgencias por asma y enfermedad pulmonar obstructiva crónica en el servicio de urgencias de un hospital. Estudio de concordancia.

OBJECTIVE: To analyse the reliability of the obtained results in the identification of cases of asthma and chronic obstructive pulmonary disease (COPD) diagnosed in the medical records of the emergency rooms of the <> of Valencia, Spain. METHODS: In the context of a study on the relationship between emergency rooms for asthma and COPD and specific environmental risks, we revised all the emergency rooms medical records of people aged over 14 attended at the <> of Valencia, Spain, during 1993 and 1994. The observers were two nurses who received previous training in the identification of cases. One observer revised the year 1993 and the other one 1994. To evaluate the reliability of the results we obtained a 24 days sample for each year and we estimated the inter-observer agreement using the Proportion of Observed Agreement (POA) and the Kappa Index (KI) and the 95 % confidence intervals (95% CI). We also carried out a specific analysis for each study category estimating the specific Kappa Index and the Proportions of Specific Agreement (PSA). To assess the inter-observer agreement we used the first 59 days of 1994, to estimate the same indexes mentioned above. RESULTS: In the total of emergency rooms, the POA for both observers was 0.99 and the KI was 0.91 (95% CI: 0.88-0.94) for the first observer and 0.79 (0.76-0.82) for the second one. In the specific analysis the PSA for <> versus <> were 0.92 (0.75-1) and 0.48 (0.31-0. 66) respectively. For the analysis of <> versus <> the PSA were 0.78 (0.69-0.87) and 0.75 (0.64-0.86). In the inter-observer agreement study we obtained, for the overall analysis, a POA equal to 0.99 and a KI to 0.87 (0.86-0.88). In the specific study the PSA for <> versus <> were 0.64 (0.53-0. 74) and 0.82 (0.77-0.87) for <> versus <>. CONCLUSIONS: The consistency of the results is good for both observers, but better for the first observer, particularly for asthma. For the COPD category the results are more homogeneous, showing a good concordance for both observers. The results for the inter-observer study also show a good reliability.

[Incidence of pulmonary tuberculosis: application of the capture-recapture method]. / Incidencia de tuberculosis pulmonar: aplicación del método de captura-recaptura.

OBJECTIVE: To determine as accurately as possible the incidence of pulmonary tuberculosis within Health Area 15 of the Community of Valencia during the period 1990-1993, using the capture-recapture method. METHOD: Descriptive study on the population of Health Area 15 (population: -139.903) divided into 4 large groups according to age (0-14, 15-34, 34-54 and 55+). Data was obtained from the statutory notification system of infectious disease (SNSID) and from the registry of the said area's Hospital Microbiology SERVICE: The main variable under study was the number of cases of pulmonary tuberculosis, both as notified under the SNSID and in terms of cases in the microbiology register in which M. tuberculosis was isolated. The incidence-rates were calculated by age and year of study for both registries employing the capture-recapture method. RESULTS: The mean annual incidence obtained for the SNSID register during the study period was 15.85 cases x 10(-5), and for the microbiology registry it was 23.29 x 10(-5). When the capture-recapture method was employed the mean annual incidence for the study period was 34.81 x 10(-5) (CI 95%: 31.82-39.92). In each of the years studied the number of cases identified was greater for the microbiology register than for the SNSID. Around half the cases of tuberculosis are below 34 years of age, with the larger section, and that having the highest incidence of tuberculosis being the 15 to 34 years age-group. There is no apparent upward trend in incidence rates calculated for this period. CONCLUSIONS: The data from the SNSID system on incidence of pulmonary tuberculosis within Health Area 15 of the Community of Valencia tends to underestimate the true incidence rate. The factual resources of the Hospital Microbiology Service are underutilized, considering the quantity and quality of information it can provide. The capture-recapture method is a good choice of method for measuring tuberculosis incidence. This method merits greater use within the field of epidemiology as much in order to assess the representativeness and thoroughness of surveillance systems as to identify inadequacies in their reporting and localisation of disease outbreaks.

[Seasonal variation in mortality in the city of Valencia, Spain]. / Variación estacional de la mortalidad en la ciudad de Valencia, España.

OBJECTIVE: To study the seasonal variation in mortality for all causes, grouped according to age and sex, within the city of Valencia during the period 1976-1990 and its relationship with air temperature. MATERIAL AND METHODS: This is an ecological study using monthly global mortality and mean atmospheric temperature statistics for the city of Valencia, Spain between 1976 and 1990. The principal variable has turned out to be mortality for all causes. Mortality rates have been determined for specific age groups (0-4, 35-49, 50-64, 65-74 and > or = 75), as well as for both genders, within the city of Valencia for each of the 180-month period of investigation. Average monthly mortality data has been obtained and the percentage variation has been calculated. Graphical analysis has been used to examine the seasonal variation in mortality and in order to discern the nature of any relationship between atmospheric temperature and mortality. The regression line has been adjusted using the Loess method (smoothed regression motive, locally pondered). The association between mean temperature and mortality has calculated by means of multiple regression analysis controlling for trend, seasonality and period effect. RESULTS: A clear seasonal pattern emerges with mortality peaking during the Winter months and dipping during the Summer and early Autumn. The increase in mortality seen during the month of January came to 27.7% of the total mortality for females and 19.5% of the total mortality for males. By age groups, this increase was greater in the 75-plus age group. Graphically, the relationship between temperature and mortality has a V-shape appearance, with a lower mortality level when the mean daily temperature for the month in question is approximately 23 degrees Celsius. Based on this relationship, two complementary.

[Metereology and health. The relationship between environmental temperature and mortality]. / Meteorología y Salud. La relación entre la temperatura ambiental y la mortalidad.

The results are presented of a series of recent works which analyse the relationships between meteorological phenomena, especially the temperature, and mortality. An increase in mortality in winter, is a well-known phenomenon which has been examined in many countries. The most common cause of death due to temperature changes is illness affecting the breathing apparatus and circulation system. The form and magnitude of the relationship between mortality and temperature depends on a series of factors, which include the characteristics of the population and the study zone. Not only the cold, but also "heat waves", have been associated with an increase in the mortality rate. The results of several works referred to suggest that the relationship between the atmospheric temperature and mortality take the for of a "V", with the lowest rates occurring on days when the average temperature is between 16 degrees and 28 degrees, depending on the climate in the zone being studied. An important aspect to be taken into account, is the delayed effect of the variations in temperature upon mortality. This work also refers to the role that other meteorological factors such as dampness and wind might play with regard to health. Finally, consideration is given to the potential impact on health, of temperature increases owing to climatic change.

[Association of air pollution and mortality: a review of recent epidemiological studies]. / La asociación entre contaminación atmosférica y mortalidad: una revisión de los estudios epidemiológicos recientes.

The aim of this study is to present a review of the work published over the past few years which deals with the relationship between air pollution (AP) and mortality from the epidemiological perspective, by examining the evolution of methodology used in the analysis along with changes in values considered as threshold levels. A literature review was carried out on of articles published in the MEDLINE and IME databases. From this search some 40 articles were selected. The review has been centred on those studies which examine the association of AP indicators and short term mortality. The design of the paper is usually retrospective and, in almost all cases, these are ecological studies. Study populations are, most of times, inhabitants of cities or particular geographic areas, with the usual analysis being a combination of time series approach and multivariate regression. Also taken into account in the majority of this papers, apart from time variables, are other confounding factors, especially meteorological conditions. The results of the papers reviewed are presented along with their principle methodological characteristics. A series of recent studies indicate that the relationship between AP, especially small particles, and mortality may exist below the guidelines established at National and International level. This study finishes with a discussion on the most outstanding aspects of the results of the papers reviewed. Also mentioned is the difficulty of determining AP indicators, and their levels, which are linked to mortality.