Biomedical subjects

S Gauvin

Publications and source records attributed to S Gauvin.

8 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

Questionnaire or objective assessment for studying exposure to tobacco smoke among asthmatic and healthy children: The French VESTA Study.

BACKGROUND: The underreporting of environmental tobacco smoke (ETS) exposure by parents of study children may depend on the instrument used and population studied, underlining the need for questionnaire validation in specific study settings. This study explores the validity of parent-reported ETS exposure in a French multicenter study on asthma. METHODS: The study population was composed of 313 children ages 4 to 14 years. Exposure to ETS was evaluated both by questionnaires on recent ETS exposure and by assessment of urinary cotinine by an enzyme immunoassay. RESULTS: According to parents' reports, about one-third of children were exposed to ETS within the past 2 days before cotinine measurement, and on average 14.9 +/- 15.4 cigarette-equivalent were smoked in their homes. The mean urinary cotinine was 435 +/- 530 nmol/mol creatinine and increased with the reported number of cigarette-equivalents smoked at home but it did not differ between children registered as being exposed to 1-10 cigarettes and children registered as unexposed. Agreement between questionnaire and urinary cotinine was moderate to poor according to our correlation coefficient (0.22) and kappa coefficient (0.09). CONCLUSION: These results show that our questionnaire is not discriminating enough to distinguish between nonexposure and mild exposure, but reveals gradients of higher exposure.

Adolescent↗

PubMed2002

Contribution of indoor and outdoor environments to PM2.5 personal exposure of children--VESTA study.

Several studies among adult populations showed that an array of outdoor and indoor sources of particles emissions contributed to personal exposures to atmospheric particles, with tobacco smoke playing a prominent role (J. Expo. Anal. Environ. Epidemiol. 6 (1996) 57, Environ. Int. 24 (1998) 405, Arch. Environ. Health 54 (1999) 95). The Vesta study was carried out to assess the role of exposure to traffic emissions in the development of childhood asthma. In this paper, we present data on 68 children aged 8-14 years, living in the metropolitan areas of Paris (n = 30), Grenoble (n = 15) and Toulouse (n = 23), France, who continuously carried, over 48 h, a rucksack that contained an active PM2.5 sampler. Data about home indoor sources were collected by questionnaires. In parallel, daily concentrations of PM10 in ambient air were monitored by local air quality networks. The contribution of indoor and outdoor factors to personal exposures was assessed using multiple linear regression models. Average personal exposure across all children was 23.7 microg/m3 (S.D. = 19.0 microg/m3), with local means ranging from 18.2 to 29.4 microg/m3. The final model explains 36% of the total between-subjects variance, with environmental tobacco smoke contributing for more than a third to this variability; presence of pets at home, proximity of the home to urban traffic emissions, and concomitant PM10 ambient air concentrations were the other main determinants of personal exposure.

Adolescent↗

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

[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↗

PubMed1997

S2F, a leaf-specific trans-acting factor, binds to a novel cis-acting element and differentially activates the RPL21 gene.

Tissue-specific factors control the differential expression of nuclear genes encoding plastid proteins. To identify some of these factors, the light-independent spinach RPL21 gene encoding the plastid ribosomal protein L21 was chosen as a model. The RPL21 promoter organization was defined by transient and stable transfections of RPL21 promoter deletion mutants fused to a reporter gene. The following results were obtained. (1) We identified a strong core promoter, spanning the transcription start site region, sufficient to drive high levels of gene expression. (2) We identified two non-overlapping positive and negative domains, located upstream from the core promoter region, that modulate core promoter activity independently of light. (3) We found that the positive domain contains a new cis-acting element, the S2 site, related to but different from the light-responsive GT-1 binding site. We show that the S2 site binds a leaf-specific nuclear factor (named S2F). The S2 site is conserved in the promoter region of many nuclear genes encoding plastid proteins. Experiments with transgenic tobacco plants confirmed that the S2 site is critical for positive domain activity in leaf tissues. The S2 site is thus identified as a new tissue-specific, light-independent regulatory element.

Base Sequence↗

PubMed1984

[Not Available].

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Americas↗

PubMedDate not supplied

Relationships between nitrogen dioxide personal exposure and ambient air monitoring measurements among children in three French metropolitan areas: VESTA study.

In epidemiological studies, investigators have routinely used ambient air concentrations, measured by air-quality monitoring networks, to assess exposure of subjects. When there is great spatial variability of ambient air concentrations or when there are specific indoor exposures, this approach may yield substantial exposure misclassification and distort the associations between exposure and the health endpoints of interest. In 3 French metropolitan areas, the cross-sectional relationships between 48 hr of nitrogen dioxide personal exposure of 73 children and the corresponding 48-hr background ambient air concentrations were analyzed. The crude correlation between ambient air concentrations and personal exposures was poor in all cities (r2 = .009 for Grenoble, r2 = .04 for Toulouse, and r2 = .02 for Paris). These correlations were improved when the authors took into account other ambient air or indoor air sources of nitrogen dioxide emissions (the corresponding multiple linear regression, r2, increased to .43 in Grenoble, .50 in Toulouse, and .37 in Paris). The main variables that explained personal exposures were an index of traffic intensity and proximity and use of a gas cooker at home. The results of this study confirm that ambient air-monitoring site measurements are poor predictors of personal exposure. Investigators should carefully characterize the proximity of roads occupied by dense traffic to the home/school as well as indoor sources of nitric oxide emissions; both of these careful characterizations will assist researchers in the prediction of personal exposure in epidemiological studies.

Adolescent↗