Évolution de l’asthme au long cours : aspects méthodologiques et lien avec la pollution atmosphérique

Unlike most chronic diseases, which tend to get progressively worse over time, the expression of asthma is variable over time. Asthma may onset at any age and is known to clinically persist, possibly resolve, or present any combination of remissions and relapses over several years, even decades. Such long-term variability has been difficult to describe in adults as data are scarce. Through an epidemiological approach, the aim of the thesis is to gain a better understanding of the variability of asthma expression over the long term in adults, in two French cohorts: the E3N study (l’Étude Épidémiologique auprès des femmes de la Mutuelle Générale de l’Éducation Nationale) and the EGEA study (the Epidemiological study on the Genetics and Environment of Asthma). The first axis is methodological and relates to the characterization of asthma expression variability over the long term. The second axis is environmental and related to the effect of air pollution on such long-term variability. Regarding the methodological axis, the in-depth analysis of answers to a single question on ever asthma repeated 7 times over 13 years in the E3N study has shown that apparently inconsistent succession of answers (positive and negative) could capture part of the medium-term variability of asthma activity, suggesting the usefulness of such approach to improve the characterization of asthma expression over time. In a context of growing interest for perceived health, a simple retrospective self-assessment of 10-year change in respiratory health has been shown to provide complementary insights to classical epidemiological and clinical tools to describe the long-term trajectory of asthma, and could predict part of the asthma evolution. Following a recent meta-analysis including 6 European cohorts (23000 participants), in which results suggest a deleterious effect of chronic ambient air pollution on asthma incidence in adults, an analysis investigated the evolution of asthma medication dispensations over 4 consecutive years, in relation with air pollution. Among the women with asthma in the E3N study, an increased estimated exposure to outdoor nitrogen dioxide and particles was associated with increased rate of controller dispensations over time, suggesting the long-term effect of air pollution on asthma progression. In conclusion, results of the thesis showed that simple tools such as several repeated answers to a single question on asthma and the self-assessment of long-term change in respiratory health may be useful in order to better characterize the variability of asthma expression over the long term, as a complementary approach alongside with classical tools. Combined with the literature, results of the thesis support the deleterious impact of chronic air pollution on progression of asthma and strengthen the need of public health interventions to reduce air pollutants concentration.Contrairement à la majorité des maladies chroniques qui s’aggravent progressivement, l’expression de l’asthme est variable au cours du temps. L’asthme peut apparaître, disparaître, s’aggraver ou s’améliorer au cours de plusieurs années, voire une décennie, à tout âge de la vie. Cette variabilité à long terme est particulièrement mal décrite chez l’adulte car les données sont rares. Par une approche épidémiologique, la thèse a pour objectif de mieux comprendre la variabilité de l’expression de l’asthme au long cours chez l’adulte dans deux cohortes françaises : E3N, l’Étude Épidémiologique auprès des femmes de la Mutuelle Générale de l’Éducation Nationale et EGEA, l’étude Épidémiologique des facteurs Génétiques et Environnementaux de l’Asthme. Le premier axe, méthodologique, porte sur la mesure de la variabilité de l’expression de l’asthme au long cours. Le second axe, environnemental, porte sur le rôle de la pollution atmosphérique sur cette variabilité. Concernant l’axe méthodologique, l’étude des réponses à une unique question sur l’asthme répétée 7 fois sur 13 ans dans le cadre de la cohorte E3N a montré qu’une succession incohérente de réponses (positives et négatives) reflétait une partie de la variabilité de l’activité de l’asthme à moyen terme, suggérant l’intérêt de cette approche pour affiner la caractérisation de l’expression de la maladie au cours du temps. Dans le contexte d’un intérêt croissant pour la santé perçue, l’étude d’une question portant sur l’auto-évaluation rétrospective du changement dans la santé respiratoire au cours des 10 dernières années a montré que l’information ainsi obtenue était complémentaire de celle d’outils épidémiologiques et cliniques existants pour décrire la trajectoire à long terme de l’asthme, et permettait de prédire en partie l’évolution de l’asthme.À la suite d’une récente méta-analyse regroupant 6 cohortes européennes (avec 23 000 participants) dont les résultats suggèrent le rôle d’une exposition chronique à la pollution atmosphérique dans l’incidence de l’asthme chez l’adulte, une analyse a porté sur l’évolution des traitements de fond et de secours de l’asthme sur une période de 4 ans en lien avec la pollution atmosphérique. Chez les femmes asthmatiques de la cohorte E3N, plus l’exposition chronique au dioxyde d’azote et aux particules était élevée, plus la consommation de corticoïdes inhalés augmentait au cours du temps, suggérant le rôle à long terme du dioxyde d’azote dans la progression de l’asthme. En conclusion, les résultats de la thèse montrent que des outils simples, tels que l’utilisation de réponses successives à une unique question sur l’asthme et l’auto-évaluation du changement dans la santé respiratoire sur 10 ans, peuvent être utilisés pour mieux caractériser la variabilité de l’expression de l’asthme au long cours, de façon complémentaire aux outils déjà existants. Associés à ceux de la littérature, les résultats de la thèse soutiennent le rôle délétère d’une exposition chronique à la pollution de l’air extérieur sur l’évolution de l’asthme au long cours et renforcent l’intérêt d’interventions de santé publique visant à diminuer la concentration des polluants atmosphériques

Predictors of Daily Mobility of Adults in Peri-Urban South India

Daily mobility, an important aspect of environmental exposures and health behavior, has mainly been investigated in high-income countries. We aimed to identify the main dimensions of mobility and investigate their individual, contextual, and external predictors among men and women living in a peri-urban area of South India. We used 192 global positioning system (GPS)-recorded mobility tracks from 47 participants (24 women, 23 men) from the Cardiovascular Health effects of Air pollution in Telangana, India (CHAI) project (mean: 4.1 days/person). The mean age was 44 (standard deviation: 14) years. Half of the population was illiterate and 55% was in unskilled manual employment, mostly agriculture-related. Sex was the largest determinant of mobility. During daytime, time spent at home averaged 13.4 (3.7) h for women and 9.4 (4.2) h for men. Women's activity spaces were smaller and more circular than men's. A principal component analysis identified three main mobility dimensions related to the size of the activity space, the mobility in/around the residence, and mobility inside the village, explaining 86% (women) and 61% (men) of the total variability in mobility. Age, socioeconomic status, and urbanicity were associated with all three dimensions. Our results have multiple potential applications for improved assessment of environmental exposures and their effects on health

Development of land-use regression models for fine particles and black carbon in peri-urban South India

Land-use regression (LUR) has been used to model local spatial variability of particulate matter in cities of high-income countries. Performance of LUR models is unknown in less urbanized areas of low-/middle-income countries (LMICs) experiencing complex sources of ambient air pollution and which typically have limited land use data. To address these concerns, we developed LUR models using satellite imagery (e.g., vegetation, urbanicity) and manually-collected data from a comprehensive built-environment survey (e.g., roads, industries, non-residential places) for a peri-urban area outside Hyderabad, India. As part of the CHAI (Cardiovascular Health effects of Air pollution in Telangana, India) project, concentrations of fine particulate matter (PM2.5) and black carbon were measured over two seasons at 23 sites. Annual mean (sd) was 34.1 (3.2) mug/m(3) for PM2.5 and 2.7 (0.5) mug/m(3) for black carbon. The LUR model for annual black carbon explained 78% of total variance and included both local-scale (energy supply places) and regional-scale (roads) predictors. Explained variance was 58% for annual PM2.5 and the included predictors were only regional (urbanicity, vegetation). During leave-one-out cross-validation and cross-holdout validation, only the black carbon model showed consistent performance. The LUR model for black carbon explained a substantial proportion of the spatial variability that could not be captured by simpler interpolation technique (ordinary kriging). This is the first study to develop a LUR model for ambient concentrations of PM2.5 and black carbon in a non-urban area of LMICs, supporting the applicability of the LUR approach in such settings. Our results provide insights on the added value of manually-collected built-environment data to improve the performance of LUR models in settings with limited data availability. For both pollutants, LUR models predicted substantial within-village variability, an important feature for future epidemiological studies

Ability of ecological deprivation indices to measure social inequalities in a French cohort

Background: Despite the increasing interest in place effect to explain health inequalities, there is currently no consensus on which kind of area-based socioeconomic measures researchers should use to assess neighborhood socioeconomic position (SEP). The study aimed to evaluate the reliability of different area-based deprivation indices (DIs) in capturing socioeconomic residential conditions of French elderly women cohort. Methods: We assessed area-based SEP using 3 DIs: Townsend Index, French European Deprivation Index (FEDI) and French Deprivation index (FDep), among women from E3N (Etude épidémiologique auprès des femmes de la Mutuelle Générale de l’Education Nationale). DIs were derived from the 2009 French census at IRIS level (smallest geographical units in France). Educational level was used to evaluate individual-SEP. To evaluate external validity of the 3 DIs, associations between two well-established socially patterned outcomes among French elderly women (smoking and overweight) and SEP, were compared. Odd ratios were computed with generalized estimating equations to control for clustering effects from participants within the same IRIS. Results: The analysis was performed among 63,888 women (aged 64, 47% ever smokers and 30% overweight). Substantial agreement was observed between the two French DIs (Kappa coefficient = 0.61) and between Townsend and FEDI (0.74) and fair agreement between Townsend and FDep (0.21). As expected among French elderly women, those with lower educational level were significantly less prone to be ever smoker (Low vs. High; OR [95% CI] = 0.43 [0.40–0.46]) and more prone to being overweight (1.89 [1.77–2.01]) than women higher educated. FDep showed expected associations at area-level for both smoking (most deprived vs. least deprived quintile; 0.77 [0.73–0.81]) and overweight (1.52 [1.44–1.62]). For FEDI opposite associations with smoking (1.13 [1.07–1.19]) and expected association with overweight (1.20 [1.13–1.28]) were observed. Townsend showed opposite associations to those expected for both smoking and overweight (1.51 [1.43–1.59]; 0.93 [0.88–0.99], respectively). Conclusion: FDep seemed reliable to capture socioeconomic residential conditions of the E3N women, more educated in average than general French population. Results varied strongly according to the DI with unexpected results for some of them, which suggested the importance to test external validity before studying social disparities in health in specific populations

Land-Use Change and Cardiometabolic Risk Factors in an Urbanizing Area of South India: A Population-Based Cohort Study.

BACKGROUND: Land-use changes in city fringes due to urbanization can lead to a reduction of greenspace that may reduce its associated health benefits. OBJECTIVES: We evaluated the association between changes in residential surrounding built-up land use and cardiometabolic risk factors in an urbanizing peri-urban area of south India and explored the mediating roles of air pollution, physical activity, and stress in these associations. METHODS: We analyzed data on 6,039 adults from the third follow-up of the Andhra Pradesh Children and Parent Study (APCAPS) cohort (2010-2012). We generated trajectories of change in residential surrounding built-up land use (buffer areas) from 1995-2009 (stable, slow increase, fast increase) using remote sensing data and image classification methods. We estimated associations between built-up land use trajectories and natural log-transformed blood pressure, waist circumference, triglycerides, fasting glucose, and non-high-density lipoprotein (non-HDL) cholesterol using linear mixed models. We accounted for multiple mediators and the multilevel structure of the data in mediation analyses. RESULTS: We observed positive associations between a fast increase in built-up land use within 300m of the home and all cardiometabolic risk factors. Compared with participants with stable trajectories, those with the largest increase in built-up land use had 1.5% (95% CI: 0.1, 2.9) higher systolic blood pressure, 2.4% (95% CI: 0.6, 4.3) higher diastolic blood pressure, 2.1% (95% CI: 0.5, 3.8) higher waist circumference, and 1.6% (95% CI: -0.6, 3.8) higher fasting glucose in fully adjusted models. Associations were positive, but not statistically significant, for triglycerides, fasting glucose, and non-HDL cholesterol. Physical activity and ambient particulate matter ≤2.5μm in aerodynamic diameter (PM2.5) partially mediated the estimated associations. Associations between fast build-up and all cardiometabolic risk factors except non-HDL cholesterol were stronger in women than men. DISCUSSION: Increases in built-up land use surrounding residences were consistently associated with higher levels of cardiometabolic risk factors. Our findings support the need for better integration of health considerations in urban planning in rapidly urbanizing settings. https://doi.org/10.1289/EHP5445

Influenza returns with a season dominated by clade 3C.2a1b.2a.2 A(H3N2) viruses, WHO European Region, 2021/22

In the WHO European Region, COVID-19 non-pharmaceutical interventions continued slowing influenza circulation in the 2021/22 season, with reduced characterisation data. A(H3) predominated and, in some countries, co-circulated with A(H1)pdm09 and B/Victoria viruses. No B/Yamagata virus detections were confirmed. Substantial proportions of characterised circulating virus subtypes or lineages differed antigenically from their respective northern hemisphere vaccine components. Appropriate levels of influenza virus characterisations should be maintained until the season end and in future seasons, when surveillance is adapted to integrate SARS-CoV-2.ECDC and WHO internal funds.S

Wearable camera-derived microenvironments in relation to personal exposure to PM2.5

Data regarding which microenvironments drive exposure to air pollution in low and middle income countries are scarce. Our objective was to identify sources of time-resolved personal PM2.5 exposure in peri-urban India using wearable camera-derived microenvironmental information. We conducted a panel study with up to 6 repeated non-consecutive 24h measurements on 45 participants (186 participant-days). Camera images were manually annotated to derive visual concepts indicative of microenvironments and activities. Men had slightly higher daily mean PM2.5 exposure (43mug/m(3)) compared to women (39mug/m(3)). Cameras helped identify that men also had higher exposures when near a biomass cooking unit (mean (sd) mug/m(3): 119 (383) for men vs 83 (196) for women) and presence in the kitchen (133 (311) for men vs 48 (94) for women). Visual concepts associated in regression analysis with higher 5-minute PM2.5 for both sexes included: smoking (+93% (95% confidence interval: 63%, 129%) in men, +29% (95% CI: 2%, 63%) in women), biomass cooking unit (+57% (95% CI: 28%, 93%) in men, +69% (95% CI: 48%, 93%) in women), visible flame or smoke (+90% (95% CI: 48%, 144%) in men, +39% (95% CI: 6%, 83%) in women), and presence in the kitchen (+49% (95% CI: 27%, 75%) in men, +14% (95% CI: 7%, 20%) in women). Our results indicate wearable cameras can provide objective, high time-resolution microenvironmental data useful for identifying peak exposures and providing insights not evident using standard self-reported time-activity