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1.  Epidemiologic Tools to Study the Influence of Environmental Factors on Fecundity and Pregnancy-related Outcomes 
Epidemiologic Reviews  2014;36(1):148-164.
Adverse pregnancy outcomes entail a large health burden for the mother and offspring; a part of it might be avoided by better understanding the role of environmental factors in their etiology. Our aims were to review the assessment tools to characterize fecundity troubles and pregnancy-related outcomes in human populations and their sensitivity to environmental factors. For each outcome, we reviewed the possible study designs, main sources of bias, and their suggested cures. In terms of study design, for most pregnancy outcomes, cohorts with recruitment early during or even before pregnancy allow efficient characterization of pregnancy-related events, time-varying confounders, and in utero exposures that may impact birth outcomes and child health. Studies on congenital anomalies require specific designs, assessment of anomalies in medical pregnancy terminations, and, for congenital anomalies diagnosed postnatally, follow-up during several months after birth. Statistical analyses should take into account environmental exposures during the relevant time windows; survival models are an appropriate approach for fecundity, fetal loss, and gestational duration/preterm delivery. Analysis of gestational duration could distinguish pregnancies according to delivery induction (and possibly pregnancy-related conditions). In conclusion, careful design and analysis are required to better characterize environmental effects on human reproduction.
PMCID: PMC3873845  PMID: 24363355
birth weight; cohort studies; congenital abnormalities; environment; fecundity; fetal membranes, premature rupture; pregnancy; preterm birth
2.  Estimating the number of homeless deaths in France, 2008–2010 
BMC Public Health  2014;14:690.
The homeless population of France has increased by 50% over the last 10 years. Studies have shown that homelessness is associated with a high risk of premature death. The aim of this study was to estimate the number of homeless deaths in France between 2008 and 2010, using a reproducible method.
We used the capture-recapture method to estimate the number of homeless deaths in France using two independent sources. An associative register of homeless deaths was matched with the national exhaustive database of the medical causes of death, using several matching approaches based on various combinations of the following variables: gender, age, place of death, date of death.
The estimated number of homeless deaths between 2008 and 2010 was 6730 (95% CI: [4381–9079]), a number greatly underestimated by the two sources considered separately (less than 20%).
In the absence of a register of the homeless deaths, the capture-recapture method provides an order of magnitude for evaluation of the resources that may be allocated by policy makers to manage the issue. Based on common and routinely produced databases, this estimate may therefore be used to monitor the mortality of the homeless population. Further studies about homeless mortality, particularly on the lead causes of deaths, are needed to manage this issue and to implement strategy to decrease the number of homeless deaths.
PMCID: PMC4227048  PMID: 24999114
Homeless; Mortality; Capture-recapture; Completeness
3.  A Pilot Study of the ELFE Longitudinal Cohort: Feasibility and Preliminary Evaluation of Biological Collection 
Biopreservation and Biobanking  2011;9(3):223-227.
Etude Longitudinale Française depuis l'Enfance (ELFE) will be a national French cohort of 20,000 children followed from birth to adulthood. Biological samples will be taken at birth to evaluate the fetal exposition to several substances. A pilot study was carried out in October 2007 to test the preanalytical factors that affected sample quality. A variety of fractions were collected by the midwife after delivery from different blood collection tubes. Options in the collection process were 2 daily transports of samples, centralized and standardized processing methodology, and storage of multiple aliquots in liquid nitrogen or at −80°C. We analyzed preanalytical factors that could have affected coagulation and then soluble CD40 Ligand (sCD40L) as a quality control tool for serum quality. Cord blood and urine were collected from 82% and 84% of women, respectively, who agreed to be followed up in the ELFE project. The use of syringe was the main factor correlated with coagulation (relative risk: 2.79 [1.47; 5.31], P<0.01). Maternity unit status was also associated with coagulation (RR: 1.48 [1.03; 2.13] in a private maternity unit vs. a public maternity) as well as time between collection and centrifugation (RR 1.03 [1; 1.07] when time between collection and centrifugation increases from 1 h). There were no extremely low sCD40L values indicating extreme exposures to room temperatures. This first evaluation study allowed us to stress the importance of carefully recording all potentially critical preanalytical variables that might be used at a large-scale level.
PMCID: PMC3178416  PMID: 21977239
4.  The Impact of Heat Islands on Mortality in Paris during the August 2003 Heat Wave 
Environmental Health Perspectives  2011;120(2):254-259.
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.
PMCID: PMC3279432  PMID: 21885383
climate change; heat wave; mortality; nighttime temperature; satellite imagery; urban heat islands; urban planning
5.  Birth Weight and Prenatal Exposure to Polychlorinated Biphenyls (PCBs) and Dichlorodiphenyldichloroethylene (DDE): A Meta-analysis within 12 European Birth Cohorts 
Environmental Health Perspectives  2011;120(2):162-170.
Objectives: Exposure to high concentrations of persistent organochlorines may cause fetal toxicity, but the evidence at low exposure levels is limited. Large studies with substantial exposure contrasts and appropriate exposure assessment are warranted. Within the framework of the EU (European Union) ENRIECO (ENvironmental Health RIsks in European Birth Cohorts) and EU OBELIX (OBesogenic Endocrine disrupting chemicals: LInking prenatal eXposure to the development of obesity later in life) projects, we examined the hypothesis that the combination of polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (DDE) adversely affects birth weight.
Methods: We used maternal and cord blood and breast milk samples of 7,990 women enrolled in 15 study populations from 12 European birth cohorts from 1990 through 2008. Using identical variable definitions, we performed for each cohort linear regression of birth weight on estimates of cord serum concentration of PCB-153 and p,p´-DDE adjusted for gestational age and a priori selected covariates. We obtained summary estimates by meta-analysis and performed analyses of interactions.
Results: The median concentration of cord serum PCB-153 was 140 ng/L (range of cohort medians 20–484 ng/L) and that of p,p´-DDE was 528 ng/L (range of cohort medians 50–1,208 ng/L). Birth weight decreased with increasing cord serum concentration of PCB-153 after adjustment for potential confounders in 12 of 15 study populations. The meta-analysis including all cohorts indicated a birth weight decline of 150 g [95% confidence interval (CI): –250, –50 g] per 1-µg/L increase in PCB-153, an exposure contrast that is close to the range of exposures across the cohorts. A 1-µg/L increase in p,p´-DDE was associated with a 7-g decrease in birth weight (95% CI: –18, 4 g).
Conclusions: The findings suggest that low-level exposure to PCB (or correlated exposures) impairs fetal growth, but that exposure to p,p´-DDE does not. The study adds to mounting evidence that low-level exposure to PCBs is inversely associated with fetal growth.
PMCID: PMC3279442  PMID: 21997443
birth cohort studies; DDE; gestational age; meta-analysis; PCBs; reproductive effects
6.  Rationales, design and recruitment for the Elfe longitudinal study 
BMC Pediatrics  2009;9:58.
Many factors act simultaneously in childhood to influence health status, life chances and well being, including pre-birth influences, the environmental pollutants of early life, health status but also the social influences of family and school. A cohort study is needed to disentangle these influences and explore attribution.
Elfe will be a nationally representative cohort of 20 000 children followed from birth to adulthood using a multidisciplinary approach. The cohort will be based on the INSEE Permanent Demographic Panel (EDP) established using census data and civil records. The sample size has been defined in order to match the representativeness criteria and to obtain some prevalence estimation, but also to address the research area of low exposure/rare effects. The cohort will be based on repeated surveys by face to face or phone interview (at birth and each year) as well as medical interview (at 2 years) and examination (at 6 years). Furthermore, biological samples will be taken at birth to evaluate the foetal exposition to toxic substances, environmental sensors will be placed in the child's homes. Pilot studies have been initiated in 2007 (500 children) with an overall acceptance rate of 55% and are currently under progress, the 2-year survey being carried out in October this year.
The longitudinal study will provide a unique source of data to analyse the development of children in their environment, to study the various factors interacting throughout the life course up to adulthood and to determine the impact of childhood experience on the individual's physical, psychological, social and professional development.
PMCID: PMC2754449  PMID: 19772571

Results 1-6 (6)