Philippe Bretin

The impact of heat islands on mortality in Paris during the August 2003 heat wave.

Background: Heat waves have a drastic impact on urban populations, which could increase with climate change. Objectives: We evaluated new indicators of elderly people’s exposure to heat in Paris, from a public health prevention perspective, using satellite thermal images. Methods: We used a time series of 61 images from the satellites of the National Oceanic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) taken from 1 to 13 August 2003 to produce thermal indicators of minimum, maximum, and mean surface temperatures and diurnal temperature amplitude, with different lags between the meteorological data and the health impact. Health data came from a case–control study involving 241 people ≥ 65 years of age who died in the city of Paris or the nearby suburban area of Val-de-Marne during the August 2003 heat wave, and 241 controls who were matched to cases on age, sex, and residential zone. For each person, we integrated the thermal indicators in a conditional logistic regression model, adjusted for age and other potential confounders. We computed odds ratios (ORs) comparing the 90th and 50th percentiles of the temperature differences between cases and controls for various indicators. Results: Mortality risk was significantly associated with exposure for two indicators: minimum temperatures averaged for 1–13 August [for a 0.41°C increase, OR = 2.17; 95% confidence interval (CI): 1.14, 4.16] and minimum temperature averaged on the day of death and the 6 preceding days (for a 0.51°C increase: OR = 2.24; 95% CI: 1.03, 4.87). Conclusions: Our results support the influence of night temperatures on the health impact of heat waves in urban areas. Urban heat exposure indicators based on satellite imagery have the potential to identify areas with higher risk of death, which could inform intervention decisions by key stakeholders.

Blood lead levels in the adult population living in France the French Nutrition and Health Survey (ENNS 2006-2007)

BACKGROUND The French Nutrition and Health Survey (ENNS) was conducted in order to describe food consumption and levels of various biomarkers in the general population. In this paper, we aimed to assess the distribution of blood lead levels (BLL) in the adult population living in France. METHOD ENNS was a cross-sectional survey carried out in the general population. Participants (18-74years of age) were sampled using a three-stage probability design stratified by geographical areas and degrees of urbanization. Collected data included biochemical samples, anthropometric measurements, socio-demographic characteristics, and environmental and occupational exposure. RESULTS In 2006/2007, 2029 adults were included in the survey on lead. The blood lead geometric mean (GM) in the population living in France was 25.7μg/L [24.9-26.5]. The overall prevalence of elevated BLL (>100μg/L) was 1.7% [1.1-2.3%]. Levels were significantly higher in males than in females, and increased with age, smoking status and alcohol consumption. Other factors significantly associated with BLL were leisure activities, occupational category, age of housing unit, birth place and shellfish/crustacean consumption. CONCLUSION For the first time a survey provides national estimates of BLL for the adult population in France. Comparison with results from a previous study among men aged 18-28years showed that the GM dropped more than 60% in the last 10years. The distribution of BLL in France was quite similar to that observed in other European countries.

Blood lead levels and risk factors in young children in France, 2008-2009.

BACKGROUND The exposure of children to lead has decreased in recent years, thanks notably to the banning of leaded gasoline. However, lead exposure remains a matter of public health concern, because no toxicity threshold has been observed, cognitive effects having been demonstrated even at low levels. It is therefore important to update exposure assessments. A national study was conducted, in 2008-2009, to determine the blood lead level (BLL) distribution in children between the ages of six months and six years in France. We also assessed the contribution of environmental factors. METHODS This cross-sectional survey included 3831 children recruited at hospitals. Two-stage probability sampling was carried out, with stratification by hospital and French region. Sociodemographic characteristics were recorded, and blood samples and environmental data were collected by questionnaire. Generalized linear model and quantile regression were used to quantify the association between BLL and environmental risk factors. RESULTS The geometric mean BLL was 14.9μg/l (95% confidence interval (CI)=[14.5-15.4]) and 0.09% of the children (95% CI=[0.03-0.15]) had BLLs exceeding 100μg/l, 1.5% (95% CI=[0.9-2.1] exceeding 50μg/l. Only slight differences were observed between French regions. Environmental factors significantly associated with BLL were the consumption of tap water in homes with lead service connections, peeling paint or recent renovations in old housing, hand-mouth behavior, passive smoking and having a mother born in a country where lead is often used. CONCLUSIONS In children between the ages of one and six years in France, lead exposure has decreased over the last 15 years as in the US and other European countries. Nevertheless still 76,000 children have BLL over 50μg/l and prevention policies must be pursued, especially keeping in mind there is no known toxicity threshold.

Screening for Elevated Blood Lead Levels in Children: Assessment of Criteria and a Proposal for New Ones in France

The decline in children’s Blood Lead Levels (BLL) raises questions about the ability of current lead poisoning screening criteria to identify those children most exposed. The objectives of the study were to evaluate the performance of current screening criteria in identifying children with blood lead levels higher than 50 µg/L in France, and to propose new criteria. Data from a national French survey, conducted among 3831 children aged 6 months to 6 years in 2008–2009 were used. The sensitivity and specificity of the current criteria in predicting blood lead levels higher than or equal to 50 µg/L were evaluated. Two predictive models of BLL above 44 µg/L (for lack of sufficient sample size at 50 µg/L) were built: the first using current criteria, and the second using newly identified risk factors. For each model, performance was studied by calculating the area under the ROC (Receiver Operating Characteristic) curve. The sensitivity of current criteria for detecting BLL higher than or equal to 50 µg/L was 0.51 (0.26; 0.75) and specificity was 0.66 (0.62; 0.70). The new model included the following criteria: foreign child newly arrived in France, mother born abroad, consumption of tap water in the presence of lead pipes, pre-1949 housing, period of construction of housing unknown, presence of peeling paint, parental smoking at home, occupancy rates for housing and child’s address in a cadastral municipality or census block comprising more than 6% of housing that is potentially unfit and built pre-1949. The area under the ROC curve was 0.86 for the new model, versus 0.76 for the current one. The lead poisoning screening criteria should be updated. The risk of industrial, occupational and hobby-related exposure could not be assessed in this study, but should be kept as screening criteria.

A contribution of an insurance foundation to the study of urban heat waves and their societal impact

B. Dousset , K. Laaidi , H. 0liviero , A. Zeghnoun , E. Giraudet , F. Gourmelon , P. Bretin , S. Vandentorren 3 1 Hawaii Institute of Geophysics and Planetology, University of Hawaii, Honolulu, HI, USA. 2 Laboratoire Géomer, UMR6554 LETG CNRS, Institut Universitaire Européen de la Mer, Plouzané, France. 3 Institut de Veille Sanitaire, Saint Maurice, France. 4 Foundation MAIF, Le Pavois, Niort, France.