Agnès Lefranc

Are the Short-term Effects of Air Pollution Restricted to Cardiorespiratory Diseases?

Short-term effects of air pollution on common morbidity are largely unknown. The authors explored links between daily levels of air pollution (nitrogen dioxide, ozone, and particulate matter less than 10 microm in diameter (PM(10))) and medical home visits made for diverse reasons in Bordeaux, France, during 2000-2006. Daily numbers of visits were obtained from a network of general practitioners. The excess relative risk (ERR) of a visit for each indicator associated with increased pollutant levels was estimated by fitting a Poisson regression model, controlling for well-known confounding factors and temporal trends. Positive and significant associations were found between air pollution and most health indicators. A 10-microg/m(3) increase in PM(10) levels was associated with increases in visits for upper and lower respiratory diseases (ERRs were 1.5% (95% confidence interval (CI): 0.3, 2.7) and 2.5% (95% CI: 0.5, 4.4), respectively), headache and asthenia (ERR = 3.5%, 95% CI: 1.3, 5.9), and skin rash and conjunctivitis (ERR = 3.2%, 95% CI: -0.2, 6.8). Significant associations were also found between nitrogen dioxide and ozone and several health indicators. Distributed-lag models showed no harvesting effect, and some effects persisted up to 15 days after exposure increased. These results suggest that considering only the most severe effects of air pollution leads to underestimation of its impact on public health.

Influence of Socioeconomic Deprivation on the Relation Between Air Pollution and β-Agonist Sales for Asthma

BACKGROUND Air pollution triggers asthma attacks hours to days after exposure. It remains unclear whether socioeconomic deprivation modulates these effects. Investigation of these interactions requires adequate statistical power, obtainable by using either a sufficient number of observations or very sensitive indicators of asthma attacks. Using a small-area temporal ecologic approach, we studied the short-term relations between ambient air pollution and sales of short-acting beta-agonist (SABA) drugs, a frequent and specific treatment for control of asthma attacks in children and young adults, and then tested the influence of deprivation on these relations. METHODS The study took place in Strasbourg, France in 2004. Health insurance funds provided data on 15,121 SABA sales for patients aged 0 to 39 years. Deprivation was estimated by small geographic areas using an index constructed from census data. Daily average ambient concentrations of particulate matter (particles with an aerodynamic diameter < 10 microm [PM(10)]), nitrogen dioxide (NO(2)), and ozone (O(3)) were modeled on a small-area level. Adjusted case-crossover models were used for statistical analysis. RESULTS Increased of 10 microg/m(3) in ambient PM(10), NO(2), and O(3) concentrations were associated, respectively, with increases of 7.5% (95% confidence interval [CI], 4 to 11.2%), 8.4% (95% CI, 5 to 11.9%), and 1% (95% CI, - 0.3 to 2.2%) in SABA sales. Deprivation had no influence on these relations. CONCLUSION The associations observed are consistent with those reported by studies focusing on SABA use. Similar studies in other settings should confirm whether the lack of interaction with deprivation is due to specific local conditions.

Air pollution and doctors' house calls for respiratory diseases in the Greater Paris area (2000-3).

This study describes the short-term relationships between the daily levels of PM10, PM2.5, NO2 and the number of doctors’ house calls for asthma, upper respiratory diseases (URD) and lower respiratory diseases (LRD) in Greater Paris for the years 2000–3. Doctors’ house calls are a relevant health indicator for the study of short-term health effects of air pollution. Indeed, it is potentially more sensitive than indicators such as general hospital admissions due to the severity of diseases motivating the call. In this study, time-series analysis was used. The daily numbers of doctor’s house calls were adjusted for time trends, seasonal factors, day of the week, influenza, weather and pollen. Up to 15 days of lag between exposure and health effects was considered using distributed lag models. A total of about 1 760 000 doctors’ house calls for all causes occurred during the study period, among which 8027 were for asthma, 52 928 for LRD and 74 845 for URD. No significant increase in risk was found between air pollution and doctors’ house calls for asthma. No significant association was found between NO2 and doctors’ house calls. An increase of 10 μg/m3 in the mean levels of PM10 and PM2.5 encountered during the 3 previous days was associated with an increase of 3% (0.8% and 5.3%) and 5.9% (2.9% and 9.0%) in the number of doctor’s house calls for URD and LRD, respectively. Considering up to 15 days between exposure and health outcomes, effects persist until 4 days after exposure and then decrease progressively. No morbidity displacement was observed. This study shows a significant heath effect of ambient particles (PM2.5 and PM10). When compared to the RRs obtained for mortality or hospital admissions in the same area, the values of the RRs obtained in this study confirm the higher sensibility of doctor’s house calls for respiratory diseases as a health indicator.

Factors associated with morbidity during the 2003 heat wave in two population-based cohorts of elderly subjects: PAQUID and Three City

Introduction France was affected in early August 2003 by a heat wave with an exceptional health impact. Many studies on mortality were conducted but few data are available on morbidity. The objectives of this study were to describe the impact of the 2003 heat wave in the general population of elderly people and to determine individual factors associated with morbidity. Methods A cross-sectional study nested in two prospective cohorts, the PAQUID and the Three-City (3C) studies, was performed. The sample included 2295 subjects from the general population, aged 67 and over who were interviewed by a phone questionnaire to complete data available in the database of the two cohorts. Two variables assessing morbidity (felt by the person and objectively observed) were created. Relationship between morbidity and individual factors were explored in univariate analyses; then multiple logistic regressions were conducted. Results During the heat wave, 8.8% of the subjects felt a deterioration of their health, and 7.8% declared an objective morbid outcome. In the univariate analyses, many factors were associated with morbidity. After multiple adjustments, few associations were still observed but some factors were associated with a decreased risk (presence of a bathroom, dressing lighter than usually) or an increased risk (stopping usual activities, presence of chronic diseases). Conclusion This study showed a non-negligible impact of the 2003 heat wave in term of felt and objective morbidity. Several individual factors were shown to be associated with morbidity and should be taken into account for the elaboration of prevention plans.

Association between long-term exposure to air pollution and mortality in France: A 25-year follow-up study

INTRODUCTION Long-term exposure to air pollution (AP) has been shown to have an impact on mortality in numerous countries, but since 2005 no data exists for France. OBJECTIVES We analyzed the association between long-term exposure to air pollution and mortality at the individual level in a large French cohort followed from 1989 to 2013. METHODS The study sample consisted of 20,327 adults working at the French national electricity and gas company EDF-GDF. Annual exposure to PM10, PM10–2.5, PM2.5, NO2, O3, SO2, and benzene was assessed for the place of residence of participants using a chemistry-transport model and taking residential history into account. Hazard ratios were estimated using a Cox proportional-hazards regression model, adjusted for selected individual and contextual risk factors. Hazard ratios were computed for an interquartile range (IQR) increase in air pollutant concentrations. RESULTS The cohort recorded 1967 non-accidental deaths. Long-term exposures to b aseline PM2.5, PM10-25, NO2 and benzene were associated with an increase in non-accidental mortality (Hazard Ratio, HR = 1.09; 95% CI: 0.99, 1.20 per 5.9 μg/m3, PM10-25; HR=1.09; 95% CI: 1.04, 1.15 per 2.2 μg/m3, NO2: HR=1.14; 95% CI: 0.99, 1.31 per 19.3 μg/m3 and benzene: HR=1.10; 95% CI: 1.00, 1.22 per 1.7 μg/m3).The strongest association was found for PM10: HR = 1.14; 95% CI: 1.05, 1.25 per 7.8 μg/m3. PM10, PM10-25 and SO2 were associated with non-accidental mortality when using time varying exposure. No significant associations were observed between air pollution and cardiovascular and respiratory mortality. CONCLUSION Long-term exposure to fine particles, nitrogen dioxide, sulfur dioxide and benzene is associated with an increased risk of non-accidental mortality in France. Our results strengthen existing evidence that outdoor air pollution is a significant environmental risk factor for mortality. Due to the limited sample size and the nature of our study (occupational), further investigations are needed in France with a larger representative population sample.

Biomarkers of exposure to environmental contaminants in French pregnant women from the Elfe cohort in 2011

BACKGROUND As part of the perinatal component of the French Human Biomonitoring (HBM) program, biomarkers levels of various chemicals have been described among pregnant women having given birth in continental France in 2011 and who have been enrolled in the Elfe cohort (French Longitudinal Study since Childhood). This paper describes the design of the study and provides main descriptive results regarding exposure biomarkers levels. METHODS Exposure biomarkers were measured in biological samples collected at delivery from pregnant women randomly selected among the participants in the clinical and biological component of the Elfe cohort (n=4145). The geometric mean and percentiles of the levels distribution were estimated for each biomarker. The sampling design was taken into account in order to obtain estimates representative of the French pregnant women in 2011. RESULTS Results provide a nation-wide representative description of biomarker levels for important environmental contaminants among pregnant women who gave birth in France in 2011. Bisphenol A (BPA), and some metabolites of phthalates, pesticides (mainly pyrethroids), dioxins, furans, polychlorobiphenyls (PCBs), brominated flame retardants (BFRs), perfluorinated compounds (PFCs) and metals (except uranium) were quantified in almost 100% of the pregnant women. Some compounds showed a downward trend compared to previous studies (lead, mercury), but others did not (pyrethroids) and should be further monitored. CONCLUSION AND PERSPECTIVES The present results show that French pregnant women are exposed to a wide variety of pollutants, including some that have been banned or restricted in France.

L’ÉTUDE ESTEBAN

Esteban au sein du Programme national de biosurveillanceLa mise en œuvre en France d’un Programme national de biosurveillance fait l’objet d’une mention dans la loi dite « Grenelle 2 » (2009), ainsi que dans le deuxieme Plan national sante environnement (PNSE2, 2009-2013). Le pilotage operationnel de ce programme a ete confie a l’Institut de veille sanitaire (InVS), les pilotes administratifs etant les ministeres de la Sante et de l’Environnement. L’elaboration de ce programme [...]

Elements of Epidemiology

Epidemiology is defined as the study of the distribution of diseases and their determining factors [1, 2]. In the field of environmental health, it thus investigates the relationship between different aspects of environmental exposure and human health. Epidemiology does not consider individuals, but rather groups of individuals specified by some common characteristic, e.g., exposure to some given substance, a pathology, etc. It then compares these groups of individuals, for example, to answer a question like: when individuals are exposed to a given substance, are they more often affected by a certain pathology?