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W Dab

Publications and source records attributed to W Dab.

At least 37 records · Page 2Linked to original sources
PubMed2001

Air pollution and health: correlation or causality? The case of the relationship between exposure to particles and cardiopulmonary mortality.

Many epidemiologic studies have observed, in different contexts, a slight short-term relationship between particles in air and cardiopulmonary mortality, even when air quality standards were respected. The causality of this relationship is important to public health because of the number of people exposed. Our aim was to make a critical assessment of the arguments used in 15 reviews of published studies. We explain the importance of distinguishing validity from causality, and we systematically analyze the various criteria of judgment within the context of ecologic time studies. Our conclusion is that the observed relationship is valid and that most of the causality criteria are respected. It is hoped that the level of exposure of populations to these particles be reduced. In Europe, acting at the root of the problem, in particular on diesel emissions, will also enable the reduction of levels of other pollutants that can have an impact on health. In the United States, the situation is more complicated, as particles are mainly secondary. It is also essential to continue with research to become better acquainted with the determinants of personal global exposures and to better understand the toxic role of the various physicochemical factors of the particles.

Air Pollution↗
PubMed2000

Feasibility of assessing dermal exposure to PAHs of workers on gaswork sites--the SOLEX study.

Population exposure to pollutants in soil is an important public health concern. Difficult to measure, it is usually estimated using multimedia models. Modeling data predict that the skin surface is a predominant exposure route in roughly 15% of the US Superfund sites. Nonetheless, no study has confirmed these predictions. The SOLEX study was an opportunity to study the feasibility of estimating the cutaneous polycyclic aromatic hydrocarbons (PAHs: all 16 of the United States Environmental Protection Agency list) load of workers at three former manufactured gas sites, one of those being under remediation. Over two measurement periods (November 1997 and June 1998), 30 and 28 volunteers, respectively, were equipped for a single day work with five pads that collected soil particles and were placed at the neck, shoulder, wrist, groin, and ankle. Pad contamination was observed for six of the nine workers on the site being remediated but not on other sites. The wrist pad was most often affected, followed by the neck pad, these are, the exposed regions of the body. The PAHs most frequently identified were anthracene, fluoranthene, naphthalene, phenanthrene, and pyrene, at concentrations relatively high. In conclusion, this study showed that estimating skin exposure to soil pollutants is feasible. Secondly, it suggested that only subjects in close contact with the soil had a detectable exposure to PAHs. Extension of this approach to other exposure settings is warranted, especially among children playing in polluted public or private gardens, because their games lead to frequent contact with the soil.

Administration, Cutaneous↗
PubMed2000

Urinary 1-hydroxypyrene as a biomarker of polycyclic aromatic hydrocarbons exposure of workers on a contaminated site: influence of exposure conditions.

The aim of the study was to determine the exposure levels of workers to polycyclic aromatic hydrocarbons on gasworks sites by the measurement of urinary 1-hydroxypyrene. Start-shift and end-shift urine samples were taken every day during an entire week (Monday to Friday), once in November and a second time in June. Four groups of workers were selected according to their activity. Increased exposure was only found among volunteers involved in the remediation of a site, 0.16 to 2.31 mumol/mol creatinine in non-smokers. The median of the non-smoker referent group was 0.02 mumol/mol creatinine (95% confidence interval, 0.01 to 0.04). Smokers had greater exposure levels than non-smokers in every group. Within and between variability was around 200%. Assessment of the exposure of persons on contaminated soil is possible, with the condition that the exposed subjects come in direct contact with the soil.

Analysis of Variance↗
PubMed2000

[The mission of the Director General of the Ministry of Health].

In France, the health and solidarity department of Employment and solidarity Ministry have just been re-organised. The Directory General of the department of Health is experiencing a complete revision of its functions and organisation. This article presents the public health context which has been taken into account for this new organisation and explains its main principles and strategic orientations. The new organisation chart is clarified. It is made up by two departments and seven under-directions. Up to now, control and administrative supervision were predominant among Health General Direction functions. They are now oriented to administrate missions prioritizing the function of health doctrines' elaboration, of programmation, animation and coordination. As the guarantor of sanitary security, the Health General Direction has also to impulse a new partnership which does not only include health professional, social and health organisation and the economic actors: citizen in general and service users in particular have to be included to promote health democracy.

Administrative Personnel↗
PubMed1999

Validity of biomarkers in environmental health studies: the case of PAHs and benzene.

Exposure biomarkers, which have long been restricted to the framework of occupational hygiene, currently arouse increasing interest in the field of environmental pollution. To assess their validity, we propose here a conceptual framework that is based on their intrinsic characteristics and on properties related to the procedures for their analysis. The most important criteria are specificity for the toxic substance under consideration and sensitivity, that is, the ability to distinguish contrasted levels of exposure. Their analytic sensitivity and specificity are also important. Fulfilling these criteria is especially important in the context of environmental pollution, because the levels of exposure, and thus the contrasts, are low. This framework is used to assess the validity of some biomarkers for polycyclic aromatic hydrocarbons (1-hydroxypyrene and DNA adducts) and for benzene (urinary and serum benzene, trans,trans muconic acid, and S-phenylmercapturic acid). This evaluation shows that the most relevant biomarkers for estimating individual exposure to environmental pollution are 1-hydroxypyrene for polycyclic aromatic hydrocarbons and urinary benzene and S-phenylmercapturic for benzene.

Acetylcysteine↗
PubMed1999

Absenteeism and mortality of workers exposed to electromagnetic fields in the French Electricity Company.

The objective of this study was to describe the health status of electricity workers exposed to electromagnetic fields during their job. Two groups of exposed workers were studied from 1978 to 1993: the live line workers (n = 121) and the substation workers (n = 232.7) of the French Electricity Company (EDF). A control group was randomly selected from all the company non-management male employees; one control for each exposed subject was matched for the first year of employment. Absenteeism indices and mortality rates were computed and compared in the exposed and control groups. The absence rates were 1.98% in the substation workers and 2.5% in the control group (p < 0.001) and 2.7% in the live-line workers and 2.8% in the control group (NS). No effect of the length of exposure was found. However the medical causes of sickness absence were different: exposed employees had less psychiatric and respiratory diseases but more accidents at work than their control group. Relative risks of accidents at work were 1.2 95% confidence interval (CI) = 1.08-1.33[ for substation workers and 3.22 (CI = 1.78-5.88) for live line workers. EDF electromagnetic field exposed workers seemed not to be affected by any specific health problems except for an excess of accidents at work.

Absenteeism↗
PubMed1998

[Catastrophe and public health: reasons for an impasse].

ANOTHER PUBLIC HEALTH CRISIS: Coming into public view after the AIDS transfusion and the mad cow crises, asbestos-related health risks have provoked an atmosphere of panic incompatible with calmly planned public health prevention programs. The avalanche of passionate reactions has led to an inextricable dead-end situation. SCAPEGOATS: Faultfinders have accused a long list of scapegoats--scientists, physicians, experts, public health officials, industrial leaders and the media--but court actions do not favor rigorous analysis of health safety dispositions. What is needed is a pondered examination of the sinister chain of events which has made such a wasteful situation possible. MEETING PUBLIC DEMANDS: Prohibiting asbestos cannot solve the problem once and for all. Asbestos removal programs must be conducted in terms of a solid risk/benefit analysis and more generally, management of environment-related health risks must be based on specific and credible measures. Without a real rehabilitation of environmental medicine, there is a genuine risk of seeing crisis situations override public health decision making.

Asbestos↗
PubMed1998

Influenza A and B epidemic criteria based on time-series analysis of health services surveillance data.

Many countries now have epidemiological surveillance systems using health services-based indicators that allow detection of influenza epidemics. However, there is no accepted criterion for defining an influenza epidemic. An epidemic criterion has been developed, based on a time-series analysis of health services-based indicators collected on a weekly basis by a surveillance network implemented in the Paris region since 1984: the Groupe Regional d'Observation de la Grippe (GROG). For each new season, an epidemic threshold is independently defined for each health services-based indicator as the upper limit of the one-sided confidence interval of the expected value calculated from the weekly differences between the observed number of events and those predicted by a SARIMA model fitted on the non-epidemic data of previous seasons. Epidemic criteria for influenza A and B are then defined from the combination of both viral indicators and epidemic thresholds of individual health services-based indicators. Among health indicators, sick-leave data collected from GP's or the Health Insurance system, emergency home medical visits, and influenza-like-illness reported by GP's are the most sensitive indicators for the early recognition of epidemics. The exceeding of the above mentioned thresholds combined with virological data allows the specific detection of influenza A or B epidemics. This time-series method of analysing surveillance data provides early and reliable recognition of these epidemics.

Community Networks↗
PubMed1998

[Short-term modeling of the effect of air pollution on health. Example: SO2 and total mortality, Paris 1987-1999].

Since 1990, many epidemiological time series studies have provided evidence that ambient air pollution levels have adverse health effects. The ERPURS study (Evaluation des Risques de la Pollution Urbaine pour la Santé) has permitted to quantify this impact in the Paris region. This study was based on an ecological time series approach. We present, step by step, the method used, illustrated by an example: association between SO2 levels and total mortality (excluding external causes), 1987-1990. Mortality modelling has taken trend into account by a linear term, seasons by trigonometrics functions sum, day of the week effects by 6 dummy variables, temperature peak by a dummy variable, influenza epidemics by appropriate variables, mean temperature by linear and quadratic terms, relative humidity by a linear term. SO2 1 day lag was introduced in the model by a linear term. The central issue is the control of seasonal variations and long term trend. An inadequate control can lead to some spurious results. The relationship between mortality and weather variables is generally nonlinear. The use of statistical and graphical diagnostics, are necessary at each step. Time series analysis are important tools to study short term relationship between air pollutants and health indicators. The method applied in the ERPURS study is only one of the possible approaches. Whatever the method used, it is important to understand the underlying process of the data and to control for confounding factors with the appropriate method for the temporal structure of the data.

Air Pollutants↗
PubMed1997

Air pollution and doctors' house calls: results from the ERPURS system for monitoring the effects of air pollution on public health in Greater Paris, France, 1991-1995. Evaluation des Risques de la Pollution Urbaine pour la Santé.

This study examines short-term relationships between doctors' house calls and urban air pollution in Greater Paris for the period 1991-1995. Poisson regressions using nonparametric smoothing functions controlled for time trend, seasonal patterns, pollen counts, influenza epidemics, and weather. The relationship between asthma visits and air pollution was stronger for children. A relative risk (RRP95/P5) of 1.32 [95% confidence interval (CI) = 1.17-1.47)] was observed for an increase from the 5th to the 95th percentile (7-51 micrograms/m3) in daily concentrations of black smoke (BS). The risks for 24-hr sulfur dioxide and nitrogen dioxide levels were in the same range. Cardiovascular conditions, considered globally, showed weaker associations than angina pectoris/myocardial infarction, for which RRP95/P5 was 1.63 (95% CI = 1.10-2.41) in relation to ozone ambient levels. Eye conditions were exclusively related to ozone (RRP95/P5 = 1.17, 95% CI 1.02-1.33). Asthma visits and ozone showed an interaction with minimum temperature: an effect was observed only at 10 degrees C or higher. In two-pollutant models including BS with, successively, SO2, NO2, and O3, only BS and O3 effects remained stable. Along with mortality and hospital admissions, house call activity data, available on a regular basis, may be a sensitive indicator for monitoring health effects related to air pollution.

Air Pollutants↗
PubMed1996

Short term respiratory health effects of ambient air pollution: results of the APHEA project in Paris.

STUDY OBJECTIVE: To quantify the short term respiratory health effects of ambient air pollution in the Paris area. DESIGN: Time series analysis of daily pollution levels using Poisson regression. SETTING: Paris, 1987-92. MEASUREMENTS AND MAIN RESULTS: Air pollution was monitored by measurement of black smoke (BS) (15 monitoring stations), sulphur dioxide (SO2), nitrogen dioxide (NO2), particulate matter less than 13 microns in diameter (PM13), and ozone (O3) (4 stations). Daily mortality and general admissions to public hospitals due to respiratory causes were considered. The statistical analysis was based on a time series procedure using linear regression modelling followed by a Poisson regression. Meterological variables, epidemics of influenza A and B, and strikes of medical staff were included in the models. The mean daily concentration of PM13 and daily 1 hour maximum of SO2 significantly affected daily mortality from respiratory causes. An increase in the concentration of PM13 of 100 micrograms/m3 above its 5th centile value increased the risk of respiratory death by 17%. PM13 and BS were also associated with hospital admissions due to all respiratory diseases (4.1% increased risk when the BS level exceeded its 5th centile value by 100 micrograms/m3). SO2 levels consistently influenced hospital admissions for all respiratory diseases, chronic obstructive pulmonary disease, and asthma. Asthma was also correlated with NO2 levels. CONCLUSIONS: These results indicate that even though the relative risk is weak in areas with low levels of pollution, ambient air pollution, and especially particulate matter and SO2, nonetheless require attention because of the number of people exposed and the existence of high risk groups.

Adolescent↗
PubMed1996

Exploring the EMF-Melatonin Connection: A Review of the Possible Effects of 50/60-Hz Electric and Magnetic Fields on Melatonin Secretion.

This study analyzed the experimental data about the relationship between exposure to 50/60-Hz electric and magnetic fields (EMF) and melatonin secretion by the pineal gland. The authors report their results and discuss possible health consequences, in the light of epidemiologic data suggesting that breast neoplasms and depressive disorders might be related to EMF. The nocturnal peak of melatonin has been reported to be diminished, or time-shifted, or both, in rodents exposed to electric and/or magnetic fields. Current experimental data from primates and humans are insufficient to show that this change occurs in them. Epidemiologic studies of associations between EMF exposure and breast cancer and between EMF exposure and depressive disorders suggest that modifications of melatonin secretion could be a biologic signal of these effects. Nonetheless, changes in melatonin secretion cannot yet be considered a verified biologic explanation of any such association.

Journal Article↗
PubMed1996

Urban air pollution is still a public health problem in Paris.

By correlating data obtained from environmental indicators and health indicators over a five-year period, a system for measuring the effects of air pollution on health has been established and tested. Rises in air pollution levels do appear to be accompanied by increases in the relevant health problems.

Aged↗
PubMed1995

[Accidents, disasters and crises: contribution of epidemiology in th nuclear field].

The experience of the Chernobyl accident has shown the necessity of being prepared for epidemiological assessment of the death consequences of a nuclear or a radiological accident. We discuss the contribution of epidemiology in such situations, in addition to the existing tools designed to assess or manage radiological risks. From a decisional point of view, three issues are distinguished: the protection of the different population groups against ionizing radiations, the achievement of health care and the communication with the public and media. We discuss the input of epidemiological tools in both perspectives. Epidemiology may also contribute to the analysis of health events that may be observed after an accident, i.e. to assess whether these events are not statistical artifacts, whether they are an effect of the exposure to the ionizing radiations or a non specific consequence of any accident. Finally, epidemiological studies should be carried out to improve our knowledge on ionizing radiations effects with a special consideration given to the dose-effect relationships. Examples of past nuclear accidents are used to discuss these issues. The last part of this paper is focused on different research issues that should be developed for preparing epidemiological plans for nuclear accidents.

Disaster Planning↗
PubMed1995

[Uncertainty, expertise and decision making: the lessons from the Montchanin landfill].

Three epidemiological studies were conducted at the urgent request of the administrative authority of the French department of Saône-et-Loire, in order to assess the health impact of volatile emissions from an industrial wastes dump situated in the vicinity of dwellings in the city of Montchanin, France (6,000 inhabitants). These studies were implemented in the context of deep concern within the local population. Two dealt with the diagnosed morbidity before (retrospective follow-up study), or after (case-control study) the closure of the site. The third one dealt with mortality, for several causes of death liable to be related to the gazes emitted by the landfill (SMR analysis). Due to the small size of the population, these studies had limited statistical power. Despite these uncertainties, the authors claim that the decision to close the site was based on sound health considerations and recommend that the site be cleaned up. This experience illustrates the usefulness and the limitations of field epidemiological evaluations of environmental nuisances.

Bias↗