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Y Le Moullec

Publications and source records attributed to Y Le Moullec.

At least 19 recordsLinked to original sources
PubMed2004

Traffic related air pollution and incidence of childhood asthma: results of the Vesta case-control study.

STUDY OBJECTIVE: The Vesta project aims to assess the role of traffic related air pollution in the occurrence of childhood asthma. DESIGN AND SETTING: Case-control study conducted in five French metropolitan areas between 1998 and 2000. A set of 217 pairs of matched 4 to 14 years old cases and controls were investigated. An index of lifelong exposure to traffic exhausts was constructed, using retrospective information on traffic density close to all home and school addresses since birth; this index was also calculated for the 0-3 years age period to investigate the effect of early exposures. MAIN RESULTS: Adjusted on environmental tobacco smoke, personal and parental allergy, and several confounders, lifelong exposure was not associated with asthma. In contrast, associations before age of 3 were significant: odds ratios for tertiles 2 and 3 of the exposure index, relative to tertile 1, exhibited a positive trend (1.48 (95%CI = 0.7 to 3.0) and 2.28 (1.1 to 4.6)), with greater odds ratios among subjects with positive skin prick tests. CONCLUSIONS: These results suggest that traffic related pollutants might have contributed to the asthma epidemic that has taken place during the past decades among children.

Age Factors↗
PubMed2003

Indoor aldehydes: measurement of contamination levels and identification of their determinants in Paris dwellings.

The recent increased prevalence of childhood asthma and atopy has brought into question the impact of outdoor pollutants and indoor air quality. The contributory role of aldehydes to this problem and the fact that they are mainly derived from the domestic environment make them of particular interest. This study therefore measures six different aldehyde levels in Paris dwellings from potentially different sources and identifies their indoor determinants. The study was carried out in the three principal rooms of 61 flats with no previous history of complaint for olfactory nuisance or specific symptoms, two-thirds of the flats having been recently refurbished. Aldehydes were sampled in these rooms using passive samplers, and a questionnaire on potential aldehyde sources was filled out at the same time. A multiple linear regression model was used to investigate indoor aldehyde determinants. Our study revealed that propionaldehyde and benzaldehyde were of minor importance compared to formaldehyde, acetaldehyde, pentanal, and hexanal. We found that levels of these last four compounds depended on the age of wall or floor coverings (renovations less than 1 year old), smoking, and ambient parameters (carbon dioxide levels, temperature). These results could help in the assessment of indoor aldehyde emissions.

Air Pollution, Indoor↗
PubMed2002

Five epidemiological studies on transport and asthma: objectives, design and descriptive results.

A case-control study was conducted in five French metropolitan areas in order to assess the role of traffic-related air pollution in the occurrence of childhood asthma. This paper presents the study design and describes the distribution of key exposure variables. A set of 217 pairs of matched 4- to 14-year-old cases and controls were investigated (matching criteria: city, age, and gender). Current and past environmental smoke exposures, indoor allergens or air pollution sources, and personal and family atopy were assessed by standard questionnaires. When possible, direct measurements were done to check the validity of this information, on current data: skin prick tests, urine cotinine, house dust mites densities, personal exposures to, and home indoor concentrations of NO(x) and PM(2.5). Cumulative exposure to traffic-related pollutants was estimated through two indices: "traffic density" refers to a time-weighted average of the traffic density-to-road distance ratio for all home and school addresses of each child's life; "air pollution" index combines lifelong time-activity patterns and ambient air concentration estimates of NO(x), using an air dispersion model of traffic exhausts. Average current PM(2.5) personal exposure is 23.8 microg/m3 (SD=17.4), and average indoor concentrations=22.5 microg/m3 (18.2); corresponding values for NO(2) are 31.4 (13.9) and 36.1 (21.4) microg/m3. Average lifelong calculated exposures to traffic-related NO(x) emissions are 62.6 microg/m3 (43.1). The five cities show important contrasts of exposure to traffic pollutants. These data will allow comparison of lifelong exposures to indicators of traffic exhausts between cases and controls, including during early ages, while controlling for a host of known enhancers or precipitators of airway chronic inflammation and for possible confounders.

Adolescent↗
PubMed2002

Personal exposure of Paris office workers to nitrogen dioxide and fine particles.

AIMS: (1) To obtain an overall estimate of variability of personal exposure of Paris office workers to fine particles (PM(2.5)) and nitrogen dioxide (NO(2)), and to quantify their microenvironmental determinants. (2) To examine the role of potential determinants of indoor concentrations. METHODS: Sixty two office workers in a Paris municipal administration (all non-smokers) were equipped with personal samplers: passive samplers for 48 hours for NO(2) (n = 62), and active pumps for 24 hours for PM(2.5) (n = 55). Simultaneous measurements were performed in homes and offices; the local air monitoring network provided ambient concentrations. A time activity diary was used to weight measured concentrations by time spent in each microenvironment in order to estimate exposure concentrations. RESULTS: On average, PM(2.5) personal exposure (30.4 microg/m(3)) was higher than corresponding in-home (24.7 microg/m(3)) and ambient concentrations (16.7 microg/m(3)). Personal exposure to NO(2) (43.6 microg/m(3)) was significantly higher than in-home concentrations (35.1 microg/m(3)) but lower than the background outdoor level (60.1 microg/m(3)). Personal exposures to PM(2.5) and NO(2) were not significantly different from in-office concentrations. PM(2.5) and NO(2) personal exposures were not significantly correlated. In-home, in-office, in-transit, outdoor time weighted concentrations, and time spent in other indoor microenvironments explain respectively 86% and 78% of personal variations in PM(2.5) and NO(2). In-home PM(2.5) concentration was primarily influenced by exposure to environmental tobacco smoke, and secondly by the ambient level (R(2) = 0.20). NO(2) in-home concentration was affected mostly by the ambient level and gas cooking time (R(2) = 0.14). CONCLUSION: While results show the major contribution of in-home and in-office concentrations to both NO(2) and PM(2.5) personal exposures, the identification of indoor level determinants was not very conclusive.

Administrative Personnel↗
PubMed2002

[Air quality monitoring and personal exposure of children to NO(2) and fine particles].

BACKGROUND: Personal exposure to air pollutants and ambient air measurements are poorly correlated in the short term. Nevertheless, air quality surveillance data are often used to characterize exposure in epidemiological studies. This work explores a method to derive exposure estimates for a population of children, through appropriate usage of surveillance data that allows for heterogeneity of life environments. METHODS: Personal exposure (PE) to PM2.5 and NO(2) of 66 to 184 children was measured in 4 French metropolitan areas (Grenoble, Nice, Toulouse and Paris). The proposed approach provides an estimate of a "translator parameter". This method was applied to subgroups of children who differed in terms of daily time spent in areas more or less influenced by traffic emissions. RESULTS: Ambient air concentrations of NO(2) overestimated personal exposures, on average, but children whose life environments are more influenced by traffic exhausts exhibit, on average, greater PE values; as far as particles are concerned, air quality surveillance and PE values are closer. Hence, translation parameters differ according to pollutants, cities and populations. CONCLUSIONS: These results suggest that ambient air monitors can be used to assess exposure of urban populations living in areas with variable traffic intensities. However, usage of these air quality surveillance data should allow for population and pollutant characteristics.

Adolescent↗
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↗
PubMed2001

[Assessment of exposure to atmospheric particles: contribution of individual measurements].

BACKGROUND: There are few studies of individual exposure to atmospheric particles, because of the relatively bulky and noisy sampling devices. These personalized measurements, generally associated with micro-environmental measurements, are aimed at studying the distribution of individual exposure and identifying its main determinants. METHODS: A synopsis of the methods implemented in such studies (populations studied, measurements strategies, questionnaires on time-activity patterns, residences and work place) was detailed. The major results are presented and discussed from an epidemiological point of view. RESULTS: The individual exposure measured with portable devices generally were generally found to be higher than the estimations made by combining micro-environmental (outdoor and indoor) measurements and data from time-activity diaries. The difference between results of these two approaches, known as "personal cloud", remains poorly understood. Correlations between individual measurings and outdoor concentrations are weak; nevertheless, day to day variations of these two series of measurements are better related. The main determinants of individual exposure to particles are identified but a quantification of their contribution remains difficult, except for passive smoking. CONCLUSION: Personal measurements cannot be used to estimate particle exposure in large scale epidemiological studies. This exposure needs to be modelized.

Air Pollution↗
PubMed2000

Exposure of Paris taxi drivers to automobile air pollutants within their vehicles.

OBJECTIVES: To study the exposure of Parisian taxi drivers to automobile air pollutants during their professional activity. METHODS: A cross sectional study was carried out from 27 January to 27 March 1997, with measurements performed in the vehicles of 29 randomly selected drivers. Carbon monoxide (CO) content was measured over an 8 hour period by a CO portable monitor. The fine suspended particles were measured according to the black smoke index (BS), with a flow controlled portable pump provided with a cellulose filter. The nitrogen oxides, NO and NO(2) were measured with a passive sampler. RESULTS: These drivers are exposed during their professional activity to relatively high concentrations of pollutants (mean, median (SD) 3.8, 2 (1.7) ppm for CO, 168, 164 (53) micrograms/m(3) for BS, 625, 598 (224) micrograms/m(3) for NO, and 139, 131 (43) micrograms/m(3) for NO(2).) For CO the concentrations were clearly lower than the threshold values recommended by the World Health Organisation. The situation is less satisfactory for the other pollutants, especially for the BS index. All concentrations of pollutants recorded were noticeably higher than concentrations in air recorded by the ambient Parisian air monitoring network and were close to, or slightly exceeded, the concentrations measured at the fixed stations close to automobile traffic. Pollutant concentrations were also influenced greatly by weather conditions. CONCLUSION: This first French study conducted in taxi drivers shows that they are highly exposed to automobile pollutants. The results would justify a medical follow up of this occupational group.

Air Pollutants, Occupational↗
PubMed1999

Use of personal passive samplers for measurement of NO(2), NO, and O(3) levels in panel studies.

We measured personal exposure to nitrogen dioxide (NO(2)), nitrogen monoxide (NO), and ozone (O(3)), using personal passive samplers during three 4-day periods, in a panel study of asthmatics continuing the normal activities of everyday life. Fifty-five adults, mean age 42 years, 53% men, and 39 children, mean age 11 years, 67% boys, wore two Ogawa passive samplers simultaneously: one for O(3), the other for NO(2) and NO. Mean outdoor pollution was measured at a regional monitoring network. Personal exposure levels were scattered; they were (on average) higher than stationary-site levels for NO and lower for NO(2) and O(3). In adults, 41% of the variance of personal exposure to NO(2) was explained by mean stationary-site measurement levels (P<0.0001). Twenty-one percent additional variance was explained by living near a main road, not having an extractor fan over the cooker, older age, and male sex. NO and O(3) personal exposures correlated poorly with stationary-site measurements. In panel studies of the health effects of air pollution, personal exposure to NO(2) and NO can be measured satisfactorily by passive samplers: such measurements are necessary for NO but not for NO(2). For O(3), accurate personal exposure measurement remains a challenge and further technical development is required.

Activities of Daily Living↗
PubMed1998

Time-series analysis of air pollution and cause-specific mortality.

Ten large European cities provided data on daily air pollution as well as mortality from respiratory and cardiovascular mortality. We used Poisson autoregressive models that controlled for trend, season, influenza epidemics, and meteorologic influences to assess the short-term effects of air pollution at each city. We then compared and pooled the city-specific results in a meta-analysis. The pooled relative risks of daily deaths from cardiovascular conditions were 1.02 [95% confidence interval (CI) = 1.01-1.04] for a 50 microg/m3 increment in the concentration of black smoke and 1.04 (95% CI = 1.01-1.06) for an increase in sulfur dioxide levels in western European cities. For respiratory diseases, these figures were 1.04 (95% CI = 1.02-1.07) and 1.05 (95% CI = 1.03-1.07), respectively. These associations were not found in the five central European cities. Eight-hour averages of ozone were also moderately associated with daily mortality in western European cities (relative risk = 1.02; 95% CI = 1.00-1.03 for cardiovascular conditions and relative risk = 1.06; 95% CI = 1.02-1.10 for respiratory conditions). Nitrogen dioxide did not show consistent relations with daily mortality. These results are similar to previously published data and add credence to the causal interpretation of these associations at levels of air pollution close to or lower than current European standards.

Aged↗
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↗
PubMed1995

Short-term effects of air pollution on health: a European approach using epidemiological time-series data. The APHEA project: background, objectives, design.

Recent studies investigating the adverse health effects of air pollution indicate that effects exist around and below the current national and international air quality guidelines and standards. However, the difficult methodological issues involved, and the diversity of analytical techniques so far applied, hinder direct between-study comparability and the drawing of clear conclusions. The APHEA (Air Pollution on Health: European Approach) project is an attempt to provide quantitative estimates of the short-term health effects of air pollution, using an extensive data base from 10 different European countries, which represent various social, environmental and air pollution situations. Within the framework of the project, the methodology of analysing epidemiological time series data, as well as that of performing meta-analysis, are further developed and standardized. Data have been collected from 15 European cities with a total population exceeding 25 million. The exposure data consist of daily measurements of black smoke, sulphur dioxide, suspended particles, nitrogen dioxide and ozone (each available in several, though not all, cities) from already existing monitoring networks. There is substantial variability in air pollution mixtures and air pollutant levels in participating cities. The mean (24 h) levels of SO2 range 27-327 micrograms.m-3 in the winter season, and those of black smoke range 15-292 micrograms.m-3. The mean (1 h) levels of ozone in the summer season range 32-166 micrograms.m-3. The outcome data are daily counts of total and cause-specific deaths and hospital emergency admissions. Data on potential confounders (mainly meteorological and chronological variables) are also used. There is large diversity in the climatic conditions in the different cities.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1993

[Asthma, urban atmospheric pollution and the weather].

The aim of this study, which was carried out in an urban environment, was to research in to a possible relationship between temporal variations in the level of atmospheric pollution in the centre of Paris, compared to the frequency of acute dyspnoeic crises in which asthmatic patients had requested the emergency service (SOS Médecins). This study began in the first half of 1989; during this period there were 701 cases of acute asthma recorded within the Paris city boundary by "SOS Médecins". The pollutants recorded were sulphur dioxide (SO2), an index of black smoke (FN), oxides of nitrogen (NOx), ozone (O3) and soluble sulphate particles (SO4). In addition, the weather patterns were examined and pollen counts were recorded. In spite of a sub-acute episode of pollution in January and February, there was no definite increase noted in the number of emergency calls made for acute asthma. In the first three months, the number of crises were, on average, higher in association with high levels of the principal pollutants (SO2 FN, NOx, SO4) as well as with the periods of high atmospheric pressure; however, only the sulphate content and atmospheric pressure remained correlated with the daily number of asthmatic crises. In the second three months, there were some co-variations uniquely associated with sulphate particles, the atmospheric pressure, and above all the ozone level (allowing for a gap of one day). The influence of the daily variations in total pollen content or of grass pollens did not show up in this study.

Acute Disease↗
PubMed1993

[Urban asthma and habitat].

This study examines in urban area the housing conditions in asthma patients who called a first-aid association of doctors (SOS Médecins) and their relationships to symptoms. The patient population is compared with the non asthmatic population who called SOS Medecins during the same period. During the first six months of 1989, among 102,791 calls, 701 were related to acute asthma symptoms, and 100 non asthma patients were sorted at random as a control group. A telephonic questionnary has been carried out to asthmatic patients and to control group. A particular aspect of asthma in Paris is given in this study: the homogeneous distribution of asthma attacks in the different districts of Paris, (with a light prevalence in three districts of the city). Sex, age, occupation were non discriminant and no significant difference was established in housing conditions and indoor air pollution sources, between the two groups of asthma and non-asthma patients.

Adolescent↗
PubMed1993

[Urban atmospheric pollution and mortality: analysis of epidemiological studies published between 1980 and 1991].

This paper analyses 14 epidemiologic investigations (published from January 1980 to September 1991) about the relationship between urban air pollution and mortality. Air pollution indicators and mortality indicators are examined. Methods to analyse the relationships between these two kinds of indicators are classified according as they bring "qualitative information" trying to answer the question: "is there any relationship between air pollution and mortality?" or according as they try to quantify this relationship. Results are presented by author. Confounding factors and means to take them into account are described. This paper ends by a discussion about interest and limits of these studies. It emphasizes the importance of the collaboration between metrologists of urban air pollution and epidemiologists.

Air Pollutants↗