263 research outputs found
How to Control for Gestational Age in Studies Involving Environmental Effects on Fetal Growth
International audienceLette
Can atmospheric pollutants influence menstrual cycle function? Supplementary material
A few experimental studies suggest that atmospheric pollutants could affect the endocrine system, and in particular stress hormones and the hypothalamic-hypophyseal-ovarian axis, which could in turn influence menstrual cycle function. We aimed to study the possible short-term effects of atmospheric pollutants on the length of the follicular and luteal phases and on the duration of the menstrual cycle in humans. To do so, from a nation-wide study on couples' fecundity, we recruited 184 women not using contraception who collected urine samples at least every other day during one menstrual cycle, from which a progesterone metabolite was assayed, allowing estimation of the duration of the follicular and luteal phases of the cycle. Atmospheric pollution (nitrogen dioxide and particulate matter with an aerodynamical diameter below 10?m, PM10) levels were estimated from a dispersion model with a 1-km resolution combined with permanent monitoring stations measurements, allowing to estimate exposures in the 30-day, 1-10 and 11-30-day periods before the start of the menstrual cycle. Regression models allowed to quantify the change in cycle duration associated with atmospheric pollutants and adjusted for potential confounders. Follicular phase duration increased on average by 0.7 day (95% confidence interval, CI, 0.2; 1.3) for each increase by 10?g/m3 in NO2 concentration averaged over the 30 days before the cycle and by 1.6 day (95% CI, 0.3; 2.9) for each increase by 10?g/m3 in PM10. There was no strong evidence of associations of exposures in this time window with luteal phase or with total menstrual cycle durations (p>0.2). Exposures in the 1-10 day period before the cycle start were also associated with increased follicular phase duration. This study is one of the first prospective studies to suggest short-term alterations in follicular phase duration following atmospheric pollutants exposure
Maternal Exposure to Nitrogen Dioxide during Pregnancy and Offspring Birth Weight: Comparison of Two Exposure Models
International audienceThe two exposure models tended to give consistent results in terms of association with birth weight, despite the moderate concordance between exposure estimates
International Collaboration on Air Pollution and Pregnancy Outcomes (ICAPPO)
Reviews find a likely adverse effect of air pollution on perinatal outcomes, but variation of findings hinders the ability to incorporate the research into policy. The International Collaboration on Air Pollution and Pregnancy Outcomes (ICAPPO) was formed to better understand relationships between air pollution and adverse birth outcomes through standardized parallel analyses in datasets from different countries. A planning group with 10 members from 6 countries was formed to coordinate the project. Collaboration participants have datasets with air pollution values and birth outcomes. Eighteen research groups with data for approximately 20 locations in Asia, Australia, Europe, North America, and South America are participating, with most participating in an initial pilot study. Datasets generally cover the 1990s. Number of births is generally in the hundreds of thousands, but ranges from around 1,000 to about one million. Almost all participants have some measure of particulate matter, and most have ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. Strong enthusiasm for participating and a geographically-diverse range of participants should lead to understanding uncertainties about the role of air pollution in perinatal outcomes and provide decision-makers with better tools to account for pregnancy outcomes in air pollution policies
The fraction of lung cancer incidence attributable to fine particulate air pollution in France: Impact of spatial resolution of air pollution models
Outdoor air pollution is a leading environmental cause of death and cancer incidence in humans. We aimed to estimate the fraction of lung cancer incidence attributable to fine particulate matter (PM2.5) exposure in France, and secondarily to illustrate the influence of the input data and the spatial resolution of information on air pollution levels on this estimate. The population attributable fraction (PAF) was estimated using a nationwide spatially refined chemistry-transport model with a 2-km spatial resolution, neighbourhood-scale population density data, and a relative risk from a published meta-analysis. We used the WHO guideline value for PM2.5 exposure (10??g/m3) as reference. Sensitivity analyses consisted in attributing the nation-wide median exposure to all areas and using alternative input data such as reference of PM2.5 exposure level and relative risk. Population-weighted median PM2.5 level in 2005 was 13.8??g/m3; 87% of the population was exposed above the guideline value. The burden of lung cancer attributable to PM2.5 exposure corresponded to 1466 cases, or 3.6% of all cases diagnosed in 2015. Sensitivity analyses showed that the use of a national median of PM2.5 exposure would have led to an underestimation of the PAF by 11% (population-weighted median) and by 72% (median of raw concentration), suggesting that our estimates would have been higher with even more finely spatially-resolved models. When the PM2.5 reference level was replaced by the 5th percentile of country-scale exposure (4.9??g/m3), PAF increased to 7.6%. Other sensitivity analyses resulted in even higher PAFs. Improvements in air pollution are crucial for quantitative health impacts assessment studies. Actions to reduce PM2.5 levels could substantially reduce the burden of lung cancer in France
Scientific Issues Relevant to Setting Regulatory Criteria to Identify Endocrine Disrupting Substances in the European Union
Background: Endocrine disruptors (EDs) are defined by the World Health Organization (WHO) as exogenous compounds or mixtures that alter function(s) of the endocrine system and consequently cause adverse effects in an intact organism, or its progeny, or (sub)populations. European regulations on pesticides, biocides, cosmetics, and industrial chemicals require the European Commission to establish scientific criteria to define EDs.
Objectives: We address the scientific relevance of four options for the identification of EDs proposed by the European Commission. Discussion: Option 1, which does not define EDs and leads to using interim criteria unrelated to the WHO definition of EDs, is not relevant. Options 2 and 3 rely on the WHO definition of EDs, which is widely accepted by the scientific community, with option 3 introducing additional categories based on the strength of evidence (suspected EDs and endocrine-active substances). Option 4 adds potency to the WHO definition, as a decision criterion. We argue that potency is dependent on the adverse effect considered and is scientifically ambiguous, and note that potency is not used as a criterion to define other particularly hazardous substances such as carcinogens and reproductive toxicants. The use of potency requires a context that goes beyond hazard identification and corresponds to risk characterization, in which potency (or, more relevantly, the dose–response function) is combined with exposure levels.
Conclusions: There is scientific agreement regarding the adequacy of the WHO definition of
EDs. The potency concept is not relevant to the identification of particularly serious hazards such
as EDs. As is common practice for carcinogens, mutagens, and reproductive toxicants, a multi-level
classification of ED based on the WHO definition, and not considering potency, would be relevant
(corresponding to option 3 proposed by the European Commission).
Citation: Slama R, Bourguignon JP, Demeneix B, Ivell R, Panzica G, Kortenkamp A, Zoeller RT.
2016. Scientific issues relevant to setting regulatory criteria to identify endocrine disrupting
substances in the European Union. Environ Health Perspect 124:1497–1503; http://dx.doi.
org/10.1289/EHP21
Exposure to Phthalates and Phenols during Pregnancy and Offspring Size at Birth
Background: Data concerning the effects of prenatal exposures to phthalates and phenols on fetal growth are limited in humans. Previous findings suggest possible effects of some phenols on male birth weight
Assessment of metabolic phenotypic variability in children's urine using 1H NMR spectroscopy
The application of metabolic phenotyping in clinical and
epidemiological studies is limited by a poor understanding of
inter-individual, intra-individual and temporal variability in
metabolic phenotypes. Using 1H NMR spectroscopy we characterised
short-term variability in urinary metabolites measured from 20
children aged 8-9 years old. Daily spot morning, night-time and
pooled (50:50 morning and night-time) urine samples across six
days (18 samples per child) were analysed, and 44 metabolites
quantified. Intraclass correlation coefficients (ICC) and mixed
effect models were applied to assess the reproducibility and
biological variance of metabolic phenotypes. Excellent
analytical reproducibility and precision was demonstrated for
the 1H NMR spectroscopic platform (median CV 7.2%). Pooled
samples captured the best inter-individual variability with an
ICC of 0.40 (median). Trimethylamine, N-acetyl neuraminic acid,
3-hydroxyisobutyrate, 3-hydroxybutyrate/3-aminoisobutyrate,
tyrosine, valine and 3-hydroxyisovalerate exhibited the highest
stability with over 50% of variance specific to the child. The
pooled sample was shown to capture the most inter-individual
variance in the metabolic phenotype, which is of importance for
molecular epidemiology study design. A substantial proportion of
the variation in the urinary metabolome of children is specific
to the individual, underlining the potential of such data to
inform clinical and exposome studies conducted early in life
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